"Wave Launch" and Subwoofer Placement?

[Folsom]

Perhaps that is it... but a lot of these wavelengths are many feet long. You can't hear the compression until it's followed by a vacuum. I think that illustrates a fair bit about how the bass frequencies can't be pinned down so easily. You could be hearing the initial compression for awhile before the vacuum hits, but you won't know when it started, so how do you know the origination distance?

 

[christoph]

The basic idea is that you want each sub to generate a different room-interaction peak-and-dip pattern, and the sum of these multiple dissimilar peak-and-dip patterns will be much smoother than any one alone... and "smooth" bass is "fast" bass because it is the peaks (which decay into inaudibility slower than the rest of the spectrum) which make bass sound slow or boomy or unnatural.

So as a starting point, I'd suggest something like this: Place one sub in a corner (preferably a front corner), one sub somewhere along each of the two far walls (the walls "opposite" that corner), and any additional subs somewhere else but not too close to any of the others, and not in corners. Also not mirror-imaged or otherwise symmetrical with respect to any of the others. Bonus points if you can elevate one of the subs above the centerline of the room, to get significant distribution in the vertical plane as well.

If you can't follow some of those suggestions, then don't. You'll still be getting worthwhile improvement just by having multiple bass sources spread around the room.



With three subs you can get pretty good distribution of your bass sources, so I'd say three is the minimum for a distributed multisub system.



As a general principle, the in-room smoothness theoretically increases as the number of distributed bass sources increases. (I use the word "theoretical" because in practice the improvement is never quite as much as the theory predicts.) So two subs are about twice as smooth as one; four subs are about twice as smooth as two; and eight subs are grounds for a divorce in most jurisdictions.

Seriously, I don't think there is a point where adding more bass sources is acoustically detrimental, but obviously there comes a point where more subs is impractical.



That will depend on the specific situation, but I use four subs, which seems to be a "sweet spot" for me for three reasons:

First, my original target market was Maggie and Quad owners, and two monopole subs intelligently distributed have approximately the same in-room smoothness as one dipole source, thus my four small monopole subs are a good match for two dipole mains.

Second, my four 4-ohm passive subs can be wired in series-parallel to present a 4-ohm load which can be driven by a single amplifier (my Swarm system is aimed at a price point which is fairly modest by WBF standards).

And third, four small subs intelligently distributed seem to make enough of an improvement that my customers are happy. I'm sure my customers would be still happy if the Swarm had eight subs instead of four, but then I'd have a lot fewer customers in the first place!

Now IF you already have a good sub or two, then the sweet spot would probably be for you to add more. If you're "rolling your own" distributed multi-sub system, you don't need for all of the subs to go all the way down. So you can have one or two big subs, and the rest can be smaller subs which don't go as low.

Thank you very much for your elaborate answer
With this method, do all the subs receive the same signal regarding x-over frequency and volume level?
If one has different subwoofers, where would you put the best one?

Is this method also valid for homecinema or for 2-channel only?

 

[Kal Rubinson]

I take that point and the initial disturbance to be our fabled "wave launch".

If so, it is trivial and unnecessary since that is a well known and well described phenomenon and employing implies otherwise.

You can't hear the compression until it's followed by a vacuum.

Really? Where is the "vacuum?"

 

[Duke LeJeune]

Thank you very much for your elaborate answer

Thank you for wading through it all! Brevity is not my strong suit.

With this method, do all the subs receive the same signal regarding x-over frequency and volume level?

Excellent question.

I presume you're asking about using your own four(?) subs. You can set them up for stereo or send them all the same mono signal. My understanding is that recordings which have true stereo bass below 80 Hz or so are quite rare, but I don't see any reason not to set them up for stereo if you have that capability.

If your subs have phase controls, you might try this: Put the two subs on the left-hand-ish side of the room 90 degrees apart in phase from the two subs on the right-hand-ish side of the room. This technique synthesizes the low-frequency phase difference the ears might encounter in a large space. Credit to David Griesinger for this idea. Some of my customers use two amplifiers so that they can use this 90-degrees-apart ("phase quadrature") technique. Thus far to the best of my knowledge all who have tried it have liked it.

Subs which are positioned well away from the main speakers are more likely to betray their locations if they pass audible upper bass/lower midrange energy. So I suggest rolling off their top ends fairly low and fairly rapidly. A 4th order highpass filter, set no higher than 80 Hz, seems to work well.

If your mains need subwoofer help north of 80 Hz, then run the two subs closest to the mains up quite a bit higher than the two subs farthest from the mains, so that the two subs farthest from the mains can be high-pass-filtered down at a lower frequency.

Just for the sake of having a starting point I'd suggest starting with all of the highpass filter and volume level settings the same. If you are hearing the rear subs' locations, then bring down their highpass filter frequencies accordingly. Varying the highpass filter frequencies among the subs might also help them blend well with the main speakers.

If you have measurement equipment, then use that to set the controls on the subs. If not, then here is the sequence I suggest:

1. Set the level of the subs. (This makes the most audible difference.)

2. Set the highpass filter frequency for the subs. (This makes the next most audible difference.)

3. Adjust the phase controls for the subs. (This makes less audible difference.)

4. Cycle back through that sequence several times to fine-tune.

6. If the blend with the mains still needs help, try spreading apart the highpass filter frequencies of the different subs.

If one has different subwoofers, where would you put the best one?

Imo the sub that goes the deepest would probably be the one you'd want to put in a corner, or nearest to a corner.

Is this method also valid for homecinema or for 2-channel only?

It works well for both.

* * * *

Just in case it might be useful:

In "typical" size home audio rooms, a distributed multisub system results in the various subs combining in semi-random phase near the top end of the subwoofer spectrum, gradually transitioning to approximately in-phase at the bottom end. This is because at the lowest frequencies, the longest room dimension may become too short to support a standing wave. This frequency region is sometimes called the "pressure zone".

Two equal-loudness sources combining in semi-random phase sum to +3 dB, while two equal-loudness sources combining in-phase sum to +6 dB. So a distributed multisub setup may seem to have more bottom end than you expected. Too much bottom end is NOT desirable! Many of my customers plug the ports in some of their subs, which reduces the low-end output of those subs. Most of my customers who use a single amplifier reverse the polarity on one of the subs which not only corrects this over-emphasis down low but also generally improves the in-room bass smoothness. And my customers who use two amplifiers accomplish the same thing by setting the two amps' phase controls 90 degrees apart.

So if you just have one sub that goes significantly deeper than the others, it will probably be doing most of the work down in the pressure zone, and that might end up being "just right". If you find that you want either a little more or a little less very-bottom-end energy, you can adjust that one sub separately from the others.

 

[christoph]

Thank you for wading through it all! Brevity is not my strong suit.



Excellent question.

I presume you're asking about using your own four(?) subs. You can set them up for stereo or send them all the same mono signal. My understanding is that recordings which have true stereo bass below 80 Hz or so are quite rare, but I don't see any reason not to set them up for stereo if you have that capability.

If your subs have phase controls, you might try this: Put the two subs on the left-hand-ish side of the room 90 degrees apart in phase from the two subs on the right-hand-ish side of the room. This technique synthesizes the low-frequency phase difference the ears might encounter in a large space. Credit to David Griesinger for this idea. Some of my customers use two amplifiers so that they can use this 90-degrees-apart ("phase quadrature") technique. Thus far to the best of my knowledge all who have tried it have liked it.

Subs which are positioned well away from the main speakers are more likely to betray their locations if they pass audible upper bass/lower midrange energy. So I suggest rolling off their top ends fairly low and fairly rapidly. A 4th order highpass filter, set no higher than 80 Hz, seems to work well.

If your mains need subwoofer help north of 80 Hz, then run the two subs closest to the mains up quite a bit higher than the two subs farthest from the mains, so that the two subs farthest from the mains can be high-pass-filtered down at a lower frequency.

Just for the sake of having a starting point I'd suggest starting with all of the highpass filter and volume level settings the same. If you are hearing the rear subs' locations, then bring down their highpass filter frequencies accordingly. Varying the highpass filter frequencies among the subs might also help them blend well with the main speakers.

If you have measurement equipment, then use that to set the controls on the subs. If not, then here is the sequence I suggest:

1. Set the level of the subs. (This makes the most audible difference.)

2. Set the highpass filter frequency for the subs. (This makes the next most audible difference.)

3. Adjust the phase controls for the subs. (This makes less audible difference.)

4. Cycle back through that sequence several times to fine-tune.

6. If the blend with the mains still needs help, try spreading apart the highpass filter frequencies of the different subs.



Imo the sub that goes the deepest would probably be the one you'd want to put in a corner, or nearest to a corner.



It works well for both.

* * * *

Just in case it might be useful:

In "typical" size home audio rooms, a distributed multisub system results in the various subs combining in semi-random phase near the top end of the subwoofer spectrum, gradually transitioning to approximately in-phase at the bottom end. This is because at the lowest frequencies, the longest room dimension may become too short to support a standing wave. This frequency region is sometimes called the "pressure zone".

Two equal-loudness sources combining in semi-random phase sum to +3 dB, while two equal-loudness sources combining in-phase sum to +6 dB. So a distributed multisub setup may seem to have more bottom end than you expected. Too much bottom end is NOT desirable! Many of my customers plug the ports in some of their subs, which reduces the low-end output of those subs. Most of my customers who use a single amplifier reverse the polarity on one of the subs which not only corrects this over-emphasis down low but also generally improves the in-room bass smoothness. And my customers who use two amplifiers accomplish the same thing by setting the two amps' phase controls 90 degrees apart.

So if you just have one sub that goes significantly deeper than the others, it will probably be doing most of the work down in the pressure zone, and that might end up being "just right". If you find that you want either a little more or a little less very-bottom-end energy, you can adjust that one sub separately from the others.

Thanks again so much

 

[morricab]

I presume you are referring to something like a distributed multisub system, the intention of which is to smooth out the in-room bass... and for the record, ime the specific placement of the subs is generally non-critical as long as some basic rules are followed.



I assume you are talking about having the initial bass energy arrive coherently... which includes, arriving at the same time.

So, if I understand correctly, School of Thought One prioritizes smooth bass, while School of Thought Two prioritizes impact.

In my experience, "smooth bass" is what makes the biggest difference, and is a PREREQUISITE for satisfying impact... if the bass is lumpy, then the PERCEPTION of impact is lost in the mud.



Imo you are absolutely correct to trust your ears! BUT...

The ear cannot hear the bass energy of a kickdrum or kodo drum separately from the room's contribution, so what you are perceiving as "optimum impact and articulation" INCLUDES the room's effects. The reason for this is, the ear has very poor time-domain resolution at low frequencies. The ear cannot even begin to detect the presence of a bass tone from less than one wavelength, and must hear multiple wavelengths before it can begin to hear pitch. Think for a moment about how long bass wavelengths are relative to the distances to room boundaries and you will see that by the time you hear the bass, you are also hearing the room.

Mike Lavigne posted something very interesting above:



It sounds to me like Mike's acoustician got his room right to such an extent that the bass energy is exceptionally smooth throughout the room, so his twin sub towers can be placed for optimal simultaneous arrival at the listening position with no compromise to the in-room smoothness. This may well be as good as home audio bass can get, but it may not be what works best in lesser rooms.

A "best of both worlds" approach in most rooms might be possible by adjusting the delay times of each distributed sub for simultaneous first arrival at the primary listening position. Intuitively it seems to me that this would tend to maximize the tactile sensation of impact, but I would expect some equalization to be called for to fine-tune the bass smoothness.

In my experience smooth bass = "fast" bass, and whenever I have made an adjustment which improved the in-room bass smoothness the net result was better perceived impact, INCLUDING when that adjustment also de-correlated the initial bass "wavefront". So I would suggest giving priority to in-room bass smoothness over preservation of initial wavefront coherence, but I wouldn't try to talk anyone out of achieving both simultaneously.

(The reason I specified "initial" wavefront coherence is that we actually want the in-room bass energy to be de-correlated in general. Well-correlated in-room bass energy results in large peaks and dips, with those peaks decaying into inaudibility more slowly than the rest of the spectrum. Strongly de-correlated in-room bass energy is smoother in frequency response and decays into inaudibility more uniformly... and the decays matter because the longer a tone persists, the louder we perceive it to be.)

I got the most coherent bass when putting the subs close to the main speakers but out in front to get the group delay as close to correct as possible. Some of the best bass I ever heard in terms precision and impact was the Aries Cerat Symphonia speakers with Erebus subs. These were 4 meter long folded horns which were placed about 4 meters in front of the main speakers (ie. right beside the listeners because this made the wave launch correct in time. Yes it caused a bit of visual cognitive dissonance but sonically it was time coherent.

 

[rob]

Thank you for wading through it all! Brevity is not my strong suit.



Excellent question.

I presume you're asking about using your own four(?) subs. You can set them up for stereo or send them all the same mono signal. My understanding is that recordings which have true stereo bass below 80 Hz or so are quite rare, but I don't see any reason not to set them up for stereo if you have that capability.

If your subs have phase controls, you might try this: Put the two subs on the left-hand-ish side of the room 90 degrees apart in phase from the two subs on the right-hand-ish side of the room. This technique synthesizes the low-frequency phase difference the ears might encounter in a large space. Credit to David Griesinger for this idea. Some of my customers use two amplifiers so that they can use this 90-degrees-apart ("phase quadrature") technique. Thus far to the best of my knowledge all who have tried it have liked it.

Subs which are positioned well away from the main speakers are more likely to betray their locations if they pass audible upper bass/lower midrange energy. So I suggest rolling off their top ends fairly low and fairly rapidly. A 4th order highpass filter, set no higher than 80 Hz, seems to work well.

If your mains need subwoofer help north of 80 Hz, then run the two subs closest to the mains up quite a bit higher than the two subs farthest from the mains, so that the two subs farthest from the mains can be high-pass-filtered down at a lower frequency.

Just for the sake of having a starting point I'd suggest starting with all of the highpass filter and volume level settings the same. If you are hearing the rear subs' locations, then bring down their highpass filter frequencies accordingly. Varying the highpass filter frequencies among the subs might also help them blend well with the main speakers.

If you have measurement equipment, then use that to set the controls on the subs. If not, then here is the sequence I suggest:

1. Set the level of the subs. (This makes the most audible difference.)

2. Set the highpass filter frequency for the subs. (This makes the next most audible difference.)

3. Adjust the phase controls for the subs. (This makes less audible difference.)

4. Cycle back through that sequence several times to fine-tune.

6. If the blend with the mains still needs help, try spreading apart the highpass filter frequencies of the different subs.



Imo the sub that goes the deepest would probably be the one you'd want to put in a corner, or nearest to a corner.



It works well for both.

* * * *

Just in case it might be useful:

In "typical" size home audio rooms, a distributed multisub system results in the various subs combining in semi-random phase near the top end of the subwoofer spectrum, gradually transitioning to approximately in-phase at the bottom end. This is because at the lowest frequencies, the longest room dimension may become too short to support a standing wave. This frequency region is sometimes called the "pressure zone".

Two equal-loudness sources combining in semi-random phase sum to +3 dB, while two equal-loudness sources combining in-phase sum to +6 dB. So a distributed multisub setup may seem to have more bottom end than you expected. Too much bottom end is NOT desirable! Many of my customers plug the ports in some of their subs, which reduces the low-end output of those subs. Most of my customers who use a single amplifier reverse the polarity on one of the subs which not only corrects this over-emphasis down low but also generally improves the in-room bass smoothness. And my customers who use two amplifiers accomplish the same thing by setting the two amps' phase controls 90 degrees apart.

So if you just have one sub that goes significantly deeper than the others, it will probably be doing most of the work down in the pressure zone, and that might end up being "just right". If you find that you want either a little more or a little less very-bottom-end energy, you can adjust that one sub separately from the others.

Thanks for this Duke.

 

[stehno]

There seems to be two schools of thought on this.
One: The optimum placement of subs has more to do with the nulls and nodes in the listening room and;
Two: The subs should be first and foremost placed with wave launch considerations. I assume wave launch optimization being achieved by testing the impulse response of a low frequency series of pulses.

Assuming the main speakers are good to 30 Hz. Does the wave launch criteria of the subs matter?
What is the relationship between sub placement, wave launch, and phase? My subs only do 0 and 180 degrees.

There was a good article (from JLAudio?) that covered multiple sub placements in excellent detail, but I can't find it, and don't recall if this topic was covered..

Hey, Kerry. How are the new speakers burning in? I see there's already some pretty good responses to your OP but I'd like share some random thoughts on bass.

I envy your having the stacks of REL G1's. But at the same time, I can see potential for much frustration, especially with the new Bayz. It can be difficult enough dialing in a single subwoofer for superior performance - much less 6 subwoofers. In my case, I gave up years ago striving to achieve a musical bass from my mains in my new shoebox dimensioned room. I eventually bought a 15-inch sub and after much playing around (not sure I really know what I'm doing) I was only able to muster a me-too bass response with the sub taking things maybe 6Hz further south. Eventually I went back to the sub's user guide / summary sheet and really tried to read between the lines and after about 10 more adjustments, I got it. My sub is a Rythmik and luckily it seems to have enough toggle switches and knobs that I never once moved my sub since installing it 5 years ago and still achieved a musical bass.

From my somewhat naive perspective, achieving truly musical bass is as much a crapshoot as it is art and science. But boy is it worth it if / when the planets are in alignment. Then again, it's even more of a crapshoot when trying to achieve this musical bass with a pair of full-range speakers without a sub since there's usually few if any knobs and switches to tweak the mains hence, optimal placement means everything and that can be the most frustrating thing to find.

I'm curious. How are you currently tuning your subs? For example. Your subs come in different paired heights from the floor. Are you adjusting all subs all the same time with a single click of the remote or are you shutting down the majority of subs and adjusting 1 or a pair at a time? Or are they daisy chained so you have one or 2 masters with the remaining subs hardwired as slaves, if that's even an option with the REL's?

It seems from my perspective anyway, that your fine-tuning options are limited with the REL's. Does it seem that way to you? If so, then I suspect like with full-range speakers only, optimal sub placement must be paramount.

Do you know for a fact that the musical bass you're striving to achieve even exists on the recordings you're playing? I ask because not every recording will generate this musical bass. Sure if the bass is really dialed in via the mains and subs, etc, all bass will sound more musical than previously. But not every recording was engineered to capture / reproduce a vigorous tight, deep, pronounced, well-defined, and otherwise musical bass.

A few notes about musical bass:

1. The bass region is much like the playback system as a whole. Implying there's mainstream bass and then there's truly musical bass. Just like there's mainstream high-end audio and then there's truly musical high-end audio.

2. Like other parts of high-end audio, it's difficult to tell from just reading who's capturing truly musical bass. Based on some of Mike Lavigne's responses and hardware and professional consultants, I certainly get the impression he's there to at least a good degree.

3. IME, musical bass is even more elusive than achieving a musical playback system in general. But it also can be the most rewarding and exhilarating part of a playback prresentation when/if achieved no matter what you think you've accomplished elsewhere. The point being, since musical bass is potentially so elusive, it can be rather difficult to discern who is coming from what perspective when responding to your questions.

4. Just like with a mainstream high-end audio system missing so much music information, a bass region lacking this musical bass is also making so much of the bass inaudible. And it's not just a little bit missing. But when achieved so many more bass notes are "discovered" and audible. IOW, lacking a musical bass is worse than we think.

5. When achieved, there's nothing as exhilarating as listening to truly musical bass as it appears to be the foundation of the music presentation. But there's so much more than just musical bass. When this level of bass is achieved, it almost magically balances out the entire presentation, giving weight, warmth, tonality, depth, and width and height to so many other instruments as well as the presentation as a whole. Playback presentations that previously sounded a bit light or even shrill are gone as we're now hearing more warmth, tonality, and bass throughout the entire playback presentation.

A few other thoughts:

1. Regarding the wave launch thing you mentioned. Are you really just thinking about lining up drivers in unison so they're best aligned / sync'ed for the initial attack of a bass note? If so, I suspect that's probably the end game.

2. My experience with subwoofers is limited but I like to think I know what fabulously music bass sounds like. In fact, what I have right now is the 2nd best I've ever heard and pretty close to the best I've heard. The best I've heard came from a pair of full-range speakers with 11-inch woofers easily able to go down to about 23Hz and no subwoofer. Since I had already given up trying to get this musical bass in my newer room and newer speakers and after buying a subwoofer to augment didn't add much, frankly I'm still surprised I was finally able to achieve this type of musical bass from a single 15-inch sub. Perhaps it's a tribute to Rythmik's designer, their servo drivers, their many dials and switches, etc. Aside from this sub I've no other experience with Rythmik but they seem to get some pretty good feedback on their products. And for a while there, I was unimpressed enough to put my Rythmik up for sale - until I finally dialed it in. But I also realize that my sub could benefit from 2nd matching sub, or better yet an 18-inch pair of subs to achieve lower Hertz while perhaps benefit from greater power.

3. When going from so-so bass to musical bass, I've never once moved my sub since initial install 5 years ago. Perhaps by luck of the draw I originally placed the sub in a sufficiently optimal location. Then again, what's that probability? If the REL has few tuning config options/settings, then perhaps placement becomes more paramount - much like full-range mains???

4. The Duke mentioned above some good thought-provoking points. But he also suggested placing subs in the corner. He may be right but in my rather limited experience with subs, I've yet to hear any subwoofer sound anything even remotely close to musical when placed in a corner. Not saying it can't be done and since subwoofer tuning can be quite a crapshoot for some of us (me) more naive types, perhaps it can be done. Still, of those systems I've heard with subs in corners, it's only been a dismal overloaded boomy and rather ill-defined bass.

5. I suggest never underestimating the role of significant distortions induced elsewhere in the playback system. I would never say that remedying those distortions induced elsewhere in the system are a substitute for a superior-positioned pair of full-range speakers and/or a superior-tuned and placed sub. But I can say that addressing significant distortions elsewhere in the system can greatly enhance whatever type of bass one is currently getting.

6. In my current config, I'm unable to utilize the high-level inputs to my sub. But in theory anyway, I still have several reasons to question REL's (and others) take that high-level inputs are the best sonic option.

7. If per chance you're restarting from square one, maybe it would be best to remove all subs from the room but one. Configure and tune that one sub until you've achieve a truly musical bass, then install that sub's twin (2nd sub) in the exact opposite location with exact same configs. Then advance to level 2 subs, then level 3 subs.

8. I don't know if the REL's will allow but a superior cone/spike/point footer allowing the subs to settle into the sub-flooring is of real sonic benefit just as it is with speakers and components since the same principles apply regardless of object.

9. The topic of achieving a truly musical bass isn't really discussed much. This leads me to think either most have already achieved it or few even know it exists. I know where I'm putting my money here.

Sorry to be all over the bass map here but I suppose what I'm really trying to say is that in the end every sub, speaker, system config, and room combo is unique and special and different and hence, every suggestion has to be taken with a grain of salt. IOW, there's no substitution for spending time working with one's own system in their own room, right?

 

[Duke LeJeune]

Duke mentioned above some good thought-provoking points. But he also suggested placing subs in the corner. He may be right but in my rather limited experience with subs, I've yet to hear any subwoofer sound anything even remotely close to musical when placed in a corner. Not saying it can't be done and since subwoofer tuning can be quite a crapshoot for some of us (me) more naive types, perhaps it can be done. Still, of those systems I've heard with subs in corners, it's only been a dismal overloaded boomy and rather ill-defined bass.

If I came across as an advocate of placing subs in corners, then I communicated poorly.

I am an advocate of distributed multisub systems, consisting of at least three (and imo preferably four or more) intelligently-positioned subs, with perhaps one, but no more than one, in a corner.

The recommendation of one, but no more than one, in a corner comes from Earl Geddes. Quoting:

"To get the best possible LF response one needs to use multiple subs placed about the room in such a way as to maximize their independence from one another...

"1) If there are corners, then one sub should probably go in a corner. Corners have the unique characteristic of seeing all of the modes. But using two corners is not an effective use of two subs because the symmetrical situation makes these two sources less statistically independent. A less symmetrical location for the second sub would be better.

"2) One of the subs should be relatively close to the mains, but not too close. Ideal here might be to locate the first sub close to the mains, but back in a corner, if in fact the mains are pulled out slightly from the wall behind them, as they should be.

"3) The rest of the subs' locations become far less important if the first two points above are adhered to."

 

[Lagonda]

Hey, Kerry. How are the new speakers burning in? I see there's already some pretty good responses to your OP but I'd like share some random thoughts on bass.

I envy your having the stacks of REL G1's. But at the same time, I can see potential for much frustration, especially with the new Bayz. It can be difficult enough dialing in a single subwoofer for superior performance - much less 6 subwoofers. In my case, I gave up years ago striving to achieve a musical bass from my mains in my new shoebox dimensioned room. I eventually bought a 15-inch sub and after much playing around (not sure I really know what I'm doing) I was only able to muster a me-too bass response with the sub taking things maybe 6Hz further south. Eventually I went back to the sub's user guide / summary sheet and really tried to read between the lines and after about 10 more adjustments, I got it. My sub is a Rythmik and luckily it seems to have enough toggle switches and knobs that I never once moved my sub since installing it 5 years ago and still achieved a musical bass.

From my somewhat naive perspective, achieving truly musical bass is as much a crapshoot as it is art and science. But boy is it worth it if / when the planets are in alignment. Then again, it's even more of a crapshoot when trying to achieve this musical bass with a pair of full-range speakers without a sub since there's usually few if any knobs and switches to tweak the mains hence, optimal placement means everything and that can be the most frustrating thing to find.

I'm curious. How are you currently tuning your subs? For example. Your subs come in different paired heights from the floor. Are you adjusting all subs all the same time with a single click of the remote or are you shutting down the majority of subs and adjusting 1 or a pair at a time? Or are they daisy chained so you have one or 2 masters with the remaining subs hardwired as slaves, if that's even an option with the REL's?

It seems from my perspective anyway, that your fine-tuning options are limited with the REL's. Does it seem that way to you? If so, then I suspect like with full-range speakers only, optimal sub placement must be paramount.

Do you know for a fact that the musical bass you're striving to achieve even exists on the recordings you're playing? I ask because not every recording will generate this musical bass. Sure if the bass is really dialed in via the mains and subs, etc, all bass will sound more musical than previously. But not every recording was engineered to capture / reproduce a vigorous tight, deep, pronounced, well-defined, and otherwise musical bass.

A few notes about musical bass:

1. The bass region is much like the playback system as a whole. Implying there's mainstream bass and then there's truly musical bass. Just like there's mainstream high-end audio and then there's truly musical high-end audio.

2. Like other parts of high-end audio, it's difficult to tell from just reading who's capturing truly musical bass. Based on some of Mike Lavigne's responses and hardware and professional consultants, I certainly get the impression he's there to at least a good degree.

3. IME, musical bass is even more elusive than achieving a musical playback system in general. But it also can be the most rewarding and exhilarating part of a playback prresentation when/if achieved no matter what you think you've accomplished elsewhere. The point being, since musical bass is potentially so elusive, it can be rather difficult to discern who is coming from what perspective when responding to your questions.

4. Just like with a mainstream high-end audio system missing so much music information, a bass region lacking this musical bass is also making so much of the bass inaudible. And it's not just a little bit missing. But when achieved so many more bass notes are "discovered" and audible. IOW, lacking a musical bass is worse than we think.

5. When achieved, there's nothing as exhilarating as listening to truly musical bass as it appears to be the foundation of the music presentation. But there's so much more than just musical bass. When this level of bass is achieved, it almost magically balances out the entire presentation, giving weight, warmth, tonality, depth, and width and height to so many other instruments as well as the presentation as a whole. Playback presentations that previously sounded a bit light or even shrill are gone as we're now hearing more warmth, tonality, and bass throughout the entire playback presentation.

A few other thoughts:

1. Regarding the wave launch thing you mentioned. Are you really just thinking about lining up drivers in unison so they're best aligned / sync'ed for the initial attack of a bass note? If so, I suspect that's probably the end game.

2. My experience with subwoofers is limited but I like to think I know what fabulously music bass sounds like. In fact, what I have right now is the 2nd best I've ever heard and pretty close to the best I've heard. The best I've heard came from a pair of full-range speakers with 11-inch woofers easily able to go down to about 23Hz and no subwoofer. Since I had already given up trying to get this musical bass in my newer room and newer speakers and after buying a subwoofer to augment didn't add much, frankly I'm still surprised I was finally able to achieve this type of musical bass from a single 15-inch sub. Perhaps it's a tribute to Rythmik's designer, their servo drivers, their many dials and switches, etc. Aside from this sub I've no other experience with Rythmik but they seem to get some pretty good feedback on their products. And for a while there, I was unimpressed enough to put my Rythmik up for sale - until I finally dialed it in. But I also realize that my sub could benefit from 2nd matching sub, or better yet an 18-inch pair of subs to achieve lower Hertz while perhaps benefit from greater power.

3. When going from so-so bass to musical bass, I've never once moved my sub since initial install 5 years ago. Perhaps by luck of the draw I originally placed the sub in a sufficiently optimal location. Then again, what's that probability? If the REL has few tuning config options/settings, then perhaps placement becomes more paramount - much like full-range mains???

4. The Duke mentioned above some good thought-provoking points. But he also suggested placing subs in the corner. He may be right but in my rather limited experience with subs, I've yet to hear any subwoofer sound anything even remotely close to musical when placed in a corner. Not saying it can't be done and since subwoofer tuning can be quite a crapshoot for some of us (me) more naive types, perhaps it can be done. Still, of those systems I've heard with subs in corners, it's only been a dismal overloaded boomy and rather ill-defined bass.

5. I suggest never underestimating the role of significant distortions induced elsewhere in the playback system. I would never say that remedying those distortions induced elsewhere in the system are a substitute for a superior-positioned pair of full-range speakers and/or a superior-tuned and placed sub. But I can say that addressing significant distortions elsewhere in the system can greatly enhance whatever type of bass one is currently getting.

6. In my current config, I'm unable to utilize the high-level inputs to my sub. But in theory anyway, I still have several reasons to question REL's (and others) take that high-level inputs are the best sonic option.

7. If per chance you're restarting from square one, maybe it would be best to remove all subs from the room but one. Configure and tune that one sub until you've achieve a truly musical bass, then install that sub's twin (2nd sub) in the exact opposite location with exact same configs. Then advance to level 2 subs, then level 3 subs.

8. I don't know if the REL's will allow but a superior cone/spike/point footer allowing the subs to settle into the sub-flooring is of real sonic benefit just as it is with speakers and components since the same principles apply regardless of object.

9. The topic of achieving a truly musical bass isn't really discussed much. This leads me to think either most have already achieved it or few even know it exists. I know where I'm putting my money here.

Sorry to be all over the bass map here but I suppose what I'm really trying to say is that in the end every sub, speaker, system config, and room combo is unique and special and different and hence, every suggestion has to be taken with a grain of salt. IOW, there's no substitution for spending time working with one's own system in their own room, right?

Wow for someone who obviously has limited experience with subs in general and sub towers in particular, you sure like to give advice. My alarm bells go of
when i read your constant reference to “musical” bass. Subs should enhance the low frequencies if they are present, that will on some material make the presentation more musical, on others do very little. If you are getting a “musical “
enhanced bass on all music, you are probably dialed in a little bass heavy or slightly out of phase. Don’t get me wrong, that can have its own charm. Sub towers have the advantage of more evenly distributing bass into a room compared to single or even two single subs. Additionally having multiple drivers moving very little each, gives you a better chance of integrating well with fast dynamic main speakers. In my experience even driver material and amplifier topology can effect your chances of successful integration, some times it will enhance your system, in other cases it will end up muddying your mid bass.
Just my opinion of coarse.

 

[musicfirst1]

Wow for someone who obviously has limited experience with subs in general and sub towers in particular, you sure like to give advice. My alarm bells go of
when i read your constant reference to “musical” bass. Subs should enhance the low frequencies if they are present, that will on some material make the presentation more musical, on others do very little. If you are getting a “musical “
enhanced bass on all music, you are probably dialed in a little bass heavy or slightly out of phase. Don’t get me wrong, that can have its own charm. Sub towers have the advantage of more evenly distributing bass into a room compared to single or even two single subs. Additionally having multiple drivers moving very little each, gives you a better chance of integrating well with fast dynamic main speakers. In my experience even driver material and amplifier topology can effect your chances of successful integration, some times it will enhance your system, in other cases it will end up muddying your mid bass.
Just my opinion of coarse.

Did you find that playing with the phase of your sub towers located behind the mains made a difference? What do you play and listen for when you're dialing in the phase? My Rels only have a zero/180 degree switch...

 

[Lagonda]

Did you find that playing with the phase of your sub towers located behind the mains made a difference? What do you play and listen for when you're dialing in the phase? My Rels only have a zero/180 degree switch...

I have gone through a variety of different pro and high end crossovers, and phase always makes a difference to me , sometimes depending on crossover frequency .In your case placement becomes more important if you only have the 2 options. But like Duke wrote set level first then best crossover point and last phase. I normally play a variety of different music when i dial in subs, if you focus to much on bass alone, you might not hit the right point. Voices need to sound right, for me especially Van Morrison and Leonard Cohen. Bass level can vary from recording to recording, and if you constantly have a desire to turn the level up and down you have not found the right spot yet. I am very sensitive to phase differences, some people don’t hear much difference. Do yourself a favor and get white pen with temporary marker, and mark the points that sound good to you, so you have way of easily returning to them, to many dials have insufficient markings, and it is frustrating having dialed yourself out of the best point, and not being able to find it again. For me the right point is very specific, and the movement of the dial from good to bad very small. Don’t be surprised if the setting you decide on the first day, sounds to bass heavy the next day, our aural system will adjust itself after listening for a while and we might not noticed to much bass. Next day you will notice and be surprised because it sounded really good the previous day. Also never adjust until your system is warmed up, my system always sounds leaner until it is proper warmed up, and has played for awhile. Again just my own personal experience.

 

[stehno]

Wow for someone who obviously has limited experience with subs in general and sub towers in particular, you sure like to give advice.

I always thought everybody's experience was limited. But yes, my subwoofer experience is more limited than my experience with musical bass.

My alarm bells go of when i read your constant reference to “musical” bass.

One should never assume everybody's coming from the exact same perspective. Especially when it comes to high-end audio. There is a clear distinction between so-so, me-too bass and musical bass. And the fact that musical bass is rarely emphasized leads me to think it needs to be emphasized more.

Subs should enhance the low frequencies if they are present, that will on some material make the presentation more musical, on others do very little.

I was in whole agreement with this statement. That is until my final round of fine tuning with my sub. And honestly, I'm still surprised as I did not think it possible.

If you are getting a “musical “ enhanced bass on all music, you are probably dialed in a little bass heavy or slightly out of phase. Don’t get me wrong, that can have its own charm.

Understood. But I already addressed this above when I said something like not every recording is able to capture / reproduce this type of musical bass.

Sub towers have the advantage of more evenly distributing bass into a room compared to single or even two single subs. Additionally having multiple drivers moving very little each, gives you a better chance of integrating well with fast dynamic main speakers. In my experience even driver material and amplifier topology can effect your chances of successful integration, some times it will enhance your system, in other cases it will end up muddying your mid bass.
Just my opinion of coarse.

I've never listened to sub-towers but otherwise can't disagree here.

 

[LL21]

Duke,

I have a question for you that hopefully a lot of us fans of bass (and you) will enjoy...and more than a few of us have contemplated. It relates to bass...specifically 'enormous bass capability' and specifically its ability to create spacial, atmosphere foundation and true envelope that even big tower speakers cannot do on their own. So here goes...

...lets say you have a room 40' long, 18' wide and 11' tall.
...lets say you already own tower speakers...XLFs, Grande Utopia EMs, Rockport Arrakis, etc

...lets say you already know from experience that a single, big JL Gotham, Velodyne DD18+, etc takes those speakers from a 2D + some 3D detailing...into a powerful 'suggestion' of a bigger envelope due to the subterranean spacial cues

...lets say you acknowledge that a SWARM of subs enables you to even out the bass performance, AND create a less demanding load on any one bass cone...so that distortion perhaps also goes down...further enhancing that 'suggestion of envelope/space of the jazz club, symphony hall, Bat Cave, etc...

QUESTION:

- what happens in your opinion if you enable your system 'virtually UNLIMITED' access to all-out bass (with SKILLED SET UP..."Stirling Trayle Standard" shall we say)? I am talking 1400-2000 square inches of cone surface area...the equivalent of dual 6 towers of dual-18" subs...each finetuned/setup or spread around the room...


The reason for the question is because many people who have towers (older Alexandrias, older Focals)...are upgrading to XVX or Arrakis or YG...and I wonder whether that extra 15%-20% of performance in coherence, palpability, noise floor is worth it compared to spending half the money of such an upgrade...and taking an X2 and giving it 1400 square inches of effortless, "distortionless", expertly tuned bass...(yes, the 15% performance is different than the bass...but i do wonder whether many of us would miss that extra bit of detail, vs having a mind-blowingly realistic venue space due to the subs (if you believe that is what that level of bass would deliver)

...in fact, I also know owners of Arrakis who have upgraded with dual-stacks of 6 REL Subs (3 subs per stack) and been blown away by the performance (and expressly stated that 2 subs per stack was not nearly the same as adding that 3rd)...
...I have also heard of Rockport Avior owners with dual-stacks of 6 REL subs...where the subs cost more than the main speakers, i think..

Thanks for your guidance on this.

 

[dbeau]

Duke,

I have a question for you that hopefully a lot of us fans of bass (and you) will enjoy...and more than a few of us have contemplated. It relates to bass...specifically 'enormous bass capability' and specifically its ability to create spacial, atmosphere foundation and true envelope that even big tower speakers cannot do on their own. So here goes...

...lets say you have a room 40' long, 18' wide and 11' tall.
...lets say you already own tower speakers...XLFs, Grande Utopia EMs, Rockport Arrakis, etc

...lets say you already know from experience that a single, big JL Gotham, Velodyne DD18+, etc takes those speakers from a 2D + some 3D detailing...into a powerful 'suggestion' of a bigger envelope due to the subterranean spacial cues

...lets say you acknowledge that a SWARM of subs enables you to even out the bass performance, AND create a less demanding load on any one bass cone...so that distortion perhaps also goes down...further enhancing that 'suggestion of envelope/space of the jazz club, symphony hall, Bat Cave, etc...

QUESTION:

- what happens in your opinion if you enable your system 'virtually UNLIMITED' access to all-out bass (with SKILLED SET UP..."Stirling Trayle Standard" shall we say)? I am talking 1400-2000 square inches of cone surface area...the equivalent of dual 6 towers of dual-18" subs...each finetuned/setup or spread around the room...


The reason for the question is because many people who have towers (older Alexandrias, older Focals)...are upgrading to XVX or Arrakis or YG...and I wonder whether that extra 15%-20% of performance in coherence, palpability, noise floor is worth it compared to spending half the money of such an upgrade...and taking an X2 and giving it 1400 square inches of effortless, "distortionless", expertly tuned bass...(yes, the 15% performance is different than the bass...but i do wonder whether many of us would miss that extra bit of detail, vs having a mind-blowingly realistic venue space due to the subs (if you believe that is what that level of bass would deliver)

...in fact, I also know owners of Arrakis who have upgraded with dual-stacks of 6 REL Subs (3 subs per stack) and been blown away by the performance (and expressly stated that 2 subs per stack was not nearly the same as adding that 3rd)...
...I have also heard of Rockport Avior owners with dual-stacks of 6 REL subs...where the subs cost more than the main speakers, i think..

Thanks for your guidance on this.

DUKE, like LL21 I am very interested in your opinion to his query!

 

[musicfirst1]

Duke,

I have a question for you that hopefully a lot of us fans of bass (and you) will enjoy...and more than a few of us have contemplated. It relates to bass...specifically 'enormous bass capability' and specifically its ability to create spacial, atmosphere foundation and true envelope that even big tower speakers cannot do on their own. So here goes...

...lets say you have a room 40' long, 18' wide and 11' tall.
...lets say you already own tower speakers...XLFs, Grande Utopia EMs, Rockport Arrakis, etc

...lets say you already know from experience that a single, big JL Gotham, Velodyne DD18+, etc takes those speakers from a 2D + some 3D detailing...into a powerful 'suggestion' of a bigger envelope due to the subterranean spacial cues

...lets say you acknowledge that a SWARM of subs enables you to even out the bass performance, AND create a less demanding load on any one bass cone...so that distortion perhaps also goes down...further enhancing that 'suggestion of envelope/space of the jazz club, symphony hall, Bat Cave, etc...

QUESTION:

- what happens in your opinion if you enable your system 'virtually UNLIMITED' access to all-out bass (with SKILLED SET UP..."Stirling Trayle Standard" shall we say)? I am talking 1400-2000 square inches of cone surface area...the equivalent of dual 6 towers of dual-18" subs...each finetuned/setup or spread around the room...


The reason for the question is because many people who have towers (older Alexandrias, older Focals)...are upgrading to XVX or Arrakis or YG...and I wonder whether that extra 15%-20% of performance in coherence, palpability, noise floor is worth it compared to spending half the money of such an upgrade...and taking an X2 and giving it 1400 square inches of effortless, "distortionless", expertly tuned bass...(yes, the 15% performance is different than the bass...but i do wonder whether many of us would miss that extra bit of detail, vs having a mind-blowingly realistic venue space due to the subs (if you believe that is what that level of bass would deliver)

...in fact, I also know owners of Arrakis who have upgraded with dual-stacks of 6 REL Subs (3 subs per stack) and been blown away by the performance (and expressly stated that 2 subs per stack was not nearly the same as adding that 3rd)...
...I have also heard of Rockport Avior owners with dual-stacks of 6 REL subs...where the subs cost more than the main speakers, i think..

Thanks for your guidance on this.

I love my 6x12" Rel Gibraltars, which, when fine tuned over many many hours together with my previous Rockport Cygnus mains (which by themselves were -3db to 20Hz in room), added not only 5hz extension, but much, much more to the presentation than one might think.

I have tuned the system to be flat, with no boom or location information relative to the sub towers. Yet its very easy to hear the subs contribution on the bottom 2 octaves of most recordings (say below 100 hz).

People who believe that careful and systematic extension of the mains, even those mains that are good to 20hz, is meaningless or of little benefit, without actually experiencing or hearing this, are simply deluding themselves IMHO.

FYI, the subs are low passed at 20Hz for the bottom pair, 22Hz for the Middle pair and 24Hz for the top pair.

 

[Ron Resnick]

I love my 6x12" Rel Gibraltars, which, when fine tuned over many many hours together with my previous Rockport Cygnus mains (which by themselves were -3db to 20Hz in room), added not only 5hz extension, but much, much more to the presentation than one might think. View attachment 64049

Do you have an opinion on how the six G-1s with 12" drivers and Class AB amps compare to, say, four No. 25s with 15" drivers and Class D amps?

 

[musicfirst1]

Ron

I have not heard the G25's in other than show conditions, so I can't comment directly. But I'd be surprised if the result wouldn't be similar. I would expect it's just trickier to integrate 4x15s vs 6x12's, especially with the hand off to the 8" woofer towers of your Pendragons. As for class D amplification, if it's done well, I see no reason to avoid this implementation, class D amplification, to my ear is as good as A/B or A for below 100Hz response.

 

[Ron Resnick]

Thank you.

 

[LL21]

Stellar work!..and this is an example i remember seeing where you had truly gone to great lengths to go where my email to Duke Lejeune was asking for expert opinions and guidance. Thanks for posting this.

It would be great if you could describe a bit more about what exactly you experience when you say the well set up sub towers add 'much more to the presentation than one might think"

Thanks for posting!

I love my 6x12" Rel Gibraltars, which, when fine tuned over many many hours together with my previous Rockport Cygnus mains (which by themselves were -3db to 20Hz in room), added not only 5hz extension, but much, much more to the presentation than one might think.

I have tuned the system to be flat, with no boom or location information relative to the sub towers. Yet its very easy to hear the subs contribution on the bottom 2 octaves of most recordings (say below 100 hz).

People who believe that careful and systematic extension of the mains, even those mains that are good to 20hz, is meaningless or of little benefit, without actually experiencing or hearing this, are simply deluding themselves IMHO.

FYI, the subs are low passed at 20Hz for the bottom pair, 22Hz for the Middle pair and 24Hz for the top pair.
View attachment 64049