Yes, that makes sense. i did not know (forgot?) there was a Gotham Mk2...interesting. I will look it up...is it just the software that is upgraded or the speaker/sub itself?
Ultimate Low Frequency Extension
- Thread starter Ron Resnick
- Start date
Yes, that makes sense. i did not know (forgot?) there was a Gotham Mk2...interesting. I will look it up...is it just the software that is upgraded or the speaker/sub itself?
Rich of True Sound Works (Apogee restorer) recommends the XVR1 or the First Watt B4 or B5 (which looks like the same idea as the XVR1 but seems a bit simpler) for active bi-amping of Full Ranges.
ARC used to make a decent (tubed) crossover but I do not think they have one in their current line (? Did not see one with a quick search, but did see the new World of McIntosh advert, never expected to see that on the arc website, wonder if the arc brand will eventually go away?) I used one with my Maggies back in the day.
Bryston makes a good though expensive crossover (get the SUB version). DEQx is impressive if you go digital. Marchand makes some really good crossovers at a lower price point, active and passive. Pro companies like dbx, Rane, and others make analog and digital crossovers in various flavors. Sanders uses a Behringer DSP unit. miniDSP probably represents the most cost-effective digital approach but that is something most on WBF would turn up their noses at; it does have some drawbacks but seems a nice little unit.
I can get away with analog crossovers in my system because my subs have phase control, though I have switched over to running them as a mono set controlled by Dirac Live. I still need delay control as the subs are placed at different distances from the MLP. Without that, you need a unit that can compensate delay, typically an analog or digital all-pass filter. I built an APF into my original servo sub design 30+ years ago and my current (Rythmik) subs include a similar circuit. Invaluable for dialing in multiple subs in multiple locations within the room.
A lot of folk forget that room correction is DSP-based, meaning the signal is digital at some point, and most all run at around 48 kHz so high-rate DACs may be wasted if room correction is used. Since the room is much of not most of the sonic signature in most systems, with the speakers right behind, I prefer to use room correction but do like the types I can tweak to taste.
Bryston makes a good though expensive crossover (get the SUB version). DEQx is impressive if you go digital. Marchand makes some really good crossovers at a lower price point, active and passive. Pro companies like dbx, Rane, and others make analog and digital crossovers in various flavors. Sanders uses a Behringer DSP unit. miniDSP probably represents the most cost-effective digital approach but that is something most on WBF would turn up their noses at; it does have some drawbacks but seems a nice little unit.
I can get away with analog crossovers in my system because my subs have phase control, though I have switched over to running them as a mono set controlled by Dirac Live. I still need delay control as the subs are placed at different distances from the MLP. Without that, you need a unit that can compensate delay, typically an analog or digital all-pass filter. I built an APF into my original servo sub design 30+ years ago and my current (Rythmik) subs include a similar circuit. Invaluable for dialing in multiple subs in multiple locations within the room.
A lot of folk forget that room correction is DSP-based, meaning the signal is digital at some point, and most all run at around 48 kHz so high-rate DACs may be wasted if room correction is used. Since the room is much of not most of the sonic signature in most systems, with the speakers right behind, I prefer to use room correction but do like the types I can tweak to taste.
Rich of True Sound Works (Apogee restorer) recommends the XVR1 or the First Watt B4 or B5 (which looks like the same idea as the XVR1 but seems a bit simpler) for active bi-amping of Full Ranges.
You're better off with passive bi-amping using the same amplifiers on top and bottom. It's one thing to use an external low pass filter "Edit- with external subs" and still so many people get it wrong because its difficult enough but running a complex speaker with an off the shelf active crossover, forget it!
david
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Good advice. I was told something similar long ago by Paul Stubblebine concerning building an active speaker using half a dozen Bottlehead SET's and Marchand crossovers. I was really full of enthusiasm, after reading a lot about his system performance at the Tapeproject and Bottlehead forums.
Basically he told me in a polite and modest way - I have great experience and it took me a few years to develop and tune my great system, do you think that a guy with no experience can do it with success in a short time? I still thank him for his straight advice.
I wouldn't say running an active analog crossover on a complex system with mains or subs is impossible, but it does take a lot of work and a very flexible crossover that allows asymmetric slopes and settings depending on the speaker. I think the results are well worth it, but then I spent a few hundred hours getting it to sound perfect. Most people probably won't want to invest the time, so going "active" is not going to work for them.
I have a Pass Labs XVR-1 3 way run in a bandpass mode like Gary. My tri-amped system includes heavily modified Magnepan 3.6s and subs.
IMHO it's absolutely imperative to use the same make of amps on any crossover frequencies above 80-90 Hz or the system will never sound integrated (you can get away with a different bass amp for the subs without screwing up the sound below this frequency if it uses 18-24dB slopes). It's also absolutely essential to level match left and right channel signal outputs of the amplifiers using the XO's gain controls on both channels with a DVM to within a few millivolts or less than .5dB using a test signal. You will also need some speaker/room measurement capability as Nelson Pass recommends in the manual. I would say this is also required for a digital crossover. you really can end up with a mess if you don't do all this.
While the Pass is probably one of the better sounding crossovers available, there are ways it can be improved for better sound. I'm experimenting now.
True Bass During a Musical Performance - an Arbiter of Reproduction
Attend a performance of Beethoven's Missa Solemnis at Royal Albert Hall. When the 64' organ pedals/pipes are played one is transported to a different realm. Yet the chorus and the orchestra are heard clearly, nothing is "loud", but the air goes taut as does your heart and body. All that revelation for what was then a few pounds. Audiophiles need to get out more. I am an audiophile.
(In all fairness parts of the TRON movie were composed by Wendy Carlos for this instrument before it was rebuilt. I have not seen the score so I do not know if she used the lowest pedals. 16Hz may have been a harmonic of the reproduction system you heard it on.)
Your question reminds of a demo of Revel B1 subwoofer at CES a couple of years ago. It was in a small room and they were playing it at pretty high SPL with tracks that had really deep bass. There was a magazine reviewer who after a minute left in disgust because it was all too loud for him! My pant legs would flap in the wind with every bass note as it does in every type of reproduction of deep bass in other rooms of this type. Most people in the room were uncomfortable with such high SPLs at low frequencies. Of course, I loved it.
Most people have not heard such bass. And if they think they have, they really haven't unless they can report experiences like above. The rooms with best bass are usually designed for movie experiences where artificial low bass is easily generated and readily available. Play the Tron movie and watch the fight and it will throw you off your chair when there is such subsonic playback (16 Hz content from what I recall).
I don't hear such bass at rooms at high-end suites in audio shows. You have to be a fan of playing music at very high levels as our perception of bass is very low. By then the rest of the music will also be hugely loud. Half the time I have to ask these vendors to turn it up to drown out background noise let alone hearing this kind of reproduction.
So long winded answer is: do you listen to your music ultra loud now? If not, then I am not sure this kind of experience is necessary.
Attend a performance of Beethoven's Missa Solemnis at Royal Albert Hall. When the 64' organ pedals/pipes are played one is transported to a different realm. Yet the chorus and the orchestra are heard clearly, nothing is "loud", but the air goes taut as does your heart and body. All that revelation for what was then a few pounds. Audiophiles need to get out more. I am an audiophile.
(In all fairness parts of the TRON movie were composed by Wendy Carlos for this instrument before it was rebuilt. I have not seen the score so I do not know if she used the lowest pedals. 16Hz may have been a harmonic of the reproduction system you heard it on.)
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Your question reminds of a demo of Revel B1 subwoofer at CES a couple of years ago. It was in a small room and they were playing it at pretty high SPL with tracks that had really deep bass. There was a magazine reviewer who after a minute left in disgust because it was all too loud for him! My pant legs would flap in the wind with every bass note as it does in every type of reproduction of deep bass in other rooms of this type. Most people in the room were uncomfortable with such high SPLs at low frequencies. Of course, I loved it.
Are you sure it was the Revel B1 model? That has only (1) 12" driver with a mere 250 watt amp, and is -10db@ 29hz
You really can't qualify that as a subwoofer. Sub means below 20hz
In addition to procuring a well-engineered full range speaker or speaker/sub combo, there are still several things at issue here.
1. A speakers' stated verses actual frequency response are usually 2 completely different matters.
2. A given speaker's interaction with the room i.e. a speaker's inferior or superior location within a given room means pert near everything. Not just for frequency depth but particularly for its ability to more accurately and more articulately reproduce bass notes in the lower regions.
3. The room itself, its dimensions, its quirks, shortcomings, not meeting minimum requirements, etc. I'm pretty convinced there are some rooms that simply are incapable of superior bass regardless if all other requirements are met.
4. A playback system's level of resolution throughout the frequency spectrum is paramount.
That said, and though it should go without saying, nobody should expect to simply purchase a state-of-the-art level speaker and expect it to reproduce a fabulously musical bass without careful / meticulous attention to #2 and #4 above.
So what does a system sacrifice if it cannot reproduce these lowest frequencies?
Assuming we're talking say 30Hz and below, the answer is the sacrifice is actually quite large. And that goes for systems that can reproduce lowest frequencies but lack musical definition. I'm always amazed at the amount of low frequency information stemming from so many recordings. In some ways, there's nothing that compares to a playback system that is capable of a most accurate, articulate, and overall extremely well-defined musical bass. The tempo seems to increase, as does the warmth of the presentation, the accuracy of the timbre of so many instruments, the overall weight and balance of the presentation, the overall level of musicality of most every piece one might listen to, and ultimately the level of listener engagement and pleasure.
It is no easy feat to make the midrange and higher frequencies even reasonably musical. But it's a real art if one were able to truly produce even a reasonably musical bottom end from one's playback system. A truly superior musical bottom-end is all but unheard of, even by many who claim they've achieved it. Maybe that's why that region is so special.
As for reproducing depths below 18Hz or so, that's outside of my scope but the good news is that there's only a fraction of music that I listen to that may have notes lower than that. Hence, for me anyway, the ROI on reproducing bass below 18Hz would seem to run into diminishing returns real quick. But it still would be nice to have that capability when called upon.
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Ron, I think LL mentioned this, but it's worth repeating- having subs in your system recreates venue acoustics better than anything else you can do to your system.
Like everything else in this hobby, it is experiential and needs to tickle your realism triggers. But if you hear it done right and you appreciate it, there is no going back, as you are transported into that hall!
Mark Seaton
WBF Technical Expert (Speaker & Acoustics)
Obviously I'm a bit biased, but well balanced, deep bass extension delivered to the listener is highly under rated. Of course so many go simply by the spec sheet of their speakers, where in most rooms you cannot separate the room from resulting the bass performance. Please note the cases where audioguy or others have mentioned my subwoofers having extension to below 10Hz in their system, this is by design, but not by common spec. By a simple outdoor or anechoic measurement the subwoofers in question have a -/3dB window extending to 16Hz or 19Hz with a shallow roll off common to unfiltered sealed systems. The response is probably more accurately described as +0/-6dB at 16 or 19 Hz, but the shape of the roll off regularly couples to listening spaces with response extending to below 10Hz. There are exceptions that are typically explainable, and variations on the theme with rooms having more openings or very high ceilings, but the trend is clear. We are very sensitive to the balance of the lowest octaves. I say octaves intentionally, as small blips and bumps are separate from the overall, averaged balance where we can very easily hear a broad 1-2dB tilt to the lowest frequencies. Few ever pull out a microphone ($75-300 these days) to determine where they are starting, and in most cases you are seeing too many factors changed with every adjustment since things were never smoothly blended to start with.
The bit not discussed often is that with the more exotic speakers you get into very specific voicing of the speaker's response. When adding another 1-2 octaves to the response of the speaker, this can alter the balance some. The more limited the inherent bass response of the speaker, the more obvious this is likely to be. A speaker that sounds a bit lean without added extension may be a great candidate, where the smaller speakers that might have some added midbass balance might get a little thicker when real extension is added without any change to the speaker's response.
The high pass function of the speakers and how to handle this interaction is the biggest hurdle to purist audio systems. I hope we will continue to see more preamp manufacturers consider adding some high pass functionality within their electronics to better facilitate such systems. A very few already do, but it would be nice if there were more options available in the space between running full range with a subwoofer overlaid and jumping into a Trinnov Amethyst.
In terms of integrating bass , the perception is adding a filter to the mains is verboten...one has to balance the better bass and improvement in the whole sound spectrum in getting that bass right , against the angst of adding that filter and the losses it might generate...
My devialet integrated amps have high/low pass filters, configurable in both freq and from 1-4th order roll off , and delay of mains and the same in respect of sub output. all done in the digital domain..
My devialet integrated amps have high/low pass filters, configurable in both freq and from 1-4th order roll off , and delay of mains and the same in respect of sub output. all done in the digital domain..
if the filter/crossover to the bass drivers/subwoofers can be driven from a speaker terminal and not upstream of the main amplifiers, then the analog signal path to the mid bass, mid range, and highs is not compromised. the lowest octave(s) are not affected negatively by added circuits like the other higher frequencies. the trade-offs are minimal....and integration can be achieved.
OTOH if the added circuitry comes prior to the main amplification then obviously you are taking a step back from purity and it's degrees of compromise depending on how well executed.
thats what I did , used line level outputs to 4 SVS subs and a ton of dsp with them .. my G1's get an unadulterated signal
I found the swarm of subs to do what it says on the tin , smooth bass all over the room , but I found using just my mains was better at sitting position .. G1's are bass monsters.
Mark , i went to your site , you have some impressive products at very good pricing !!!. those stacks must sound amazing, ..one small criticism is the forum based approach..I struggled to find stuff and info.. rather put your line up and pricing on the home page.
I found the swarm of subs to do what it says on the tin , smooth bass all over the room , but I found using just my mains was better at sitting position .. G1's are bass monsters.
Mark , i went to your site , you have some impressive products at very good pricing !!!. those stacks must sound amazing, ..one small criticism is the forum based approach..I struggled to find stuff and info.. rather put your line up and pricing on the home page.
Hi
IN our hobby it is difficult to escape dogmas and declaration of faith. The reality is that Integration of subs with mains require flexibility. Nothing is as flexible as digital filters. Analog filters are bound to do much more harms than digital down low ... Repeating down low. I could add everywhere but ... let's leave that fight for another time
There is nothing added in term of circuitry for the Devialet or other Digital DSP to do their things, just processing and in the big scheme of things audio is a low bandwidth application wich is handled with aplomb with modern (and some last century too ) processors.
INtegration means that sometime you have to curtail the top end of the subwoofer response . IOW make sure it doesn't play over a certain frequecy range , many subwoofers do ... so while we concentrate usually on the low pass we forget the high pass. in several instances some subwoofer play loudly up to 200 Hz with often a very jagged and irregular repsonse adding much "muck" to the main response with the resulting "slow" muddy and lack of definition... and that is putting aside the intrinsic quality of the sub in the region of interest that is <50 Hz or so ...
there are many professions of faith concerning the best approach and 4 towers is good given a dedicated and well treated room and luck. Distributing subwoofers provide the best performance in most cases.
Choosing subwoofers is not an easy task: It takes a long time to integrate any subs with mains. it takes a long while to dial them in the room. It takes some education to understand good bass. I am not by any means being pedantic or condescending. Good , clean bass is quite strange at first. Most people haven't heard a clean 40 Hz let alone 20 Hz in their environment. 20 Hz is not heard, hardly so it is felt and it requires some healthy output to be perceived .. at 60 dB of SPL, 20 Hz is so faint as to not be perceived by most people's ears although your walls will likely rattle and things will shake. The problem is compounded by the fact that many subwoofers distort a lot when asked to reproduce 20 Hz at realistic output say 90 dB, > 20 % THD is not uncommon.. It is not rare for some celebrated subs, to output a lot of 60 Hz when asked to reproduce 20 Hz at say 100 dB you would find some serious 60 Hz component at 70 dB SPL which is easily heard. The better subs don't and sound strangely enough at first less "bassy" .. It takes time to understand that and notice the improvement in FR almost everywhere .. to arrive at the integration will test the patience of many audiophiles
The problems are multiple and usually the audiophile tackling subwoofer integration gets to a point where the trade-offs are not worth the results, especially when the person eschew DSP. DSp is not a panacea, not a cure-all but in the realm of subwoofer to main integration DSP is the best tool there is.
O.T.
I have to stop writing , perhaps later. For now we are bracing ourselves.. waiting to suffer from (or hopefully not) the fury of a Cat 4 hurricane moving very slowly ... the South peninsula Haiti, has already being hit with some other are waiting ... It seems to move a little bit of our coast but part of .. We'll see... Discussing with you guys takes the worry off my mind ...
IN our hobby it is difficult to escape dogmas and declaration of faith. The reality is that Integration of subs with mains require flexibility. Nothing is as flexible as digital filters. Analog filters are bound to do much more harms than digital down low ... Repeating down low. I could add everywhere but ... let's leave that fight for another time
There is nothing added in term of circuitry for the Devialet or other Digital DSP to do their things, just processing and in the big scheme of things audio is a low bandwidth application wich is handled with aplomb with modern (and some last century too ) processors.
INtegration means that sometime you have to curtail the top end of the subwoofer response . IOW make sure it doesn't play over a certain frequecy range , many subwoofers do ... so while we concentrate usually on the low pass we forget the high pass. in several instances some subwoofer play loudly up to 200 Hz with often a very jagged and irregular repsonse adding much "muck" to the main response with the resulting "slow" muddy and lack of definition... and that is putting aside the intrinsic quality of the sub in the region of interest that is <50 Hz or so ...
there are many professions of faith concerning the best approach and 4 towers is good given a dedicated and well treated room and luck. Distributing subwoofers provide the best performance in most cases.
Choosing subwoofers is not an easy task: It takes a long time to integrate any subs with mains. it takes a long while to dial them in the room. It takes some education to understand good bass. I am not by any means being pedantic or condescending. Good , clean bass is quite strange at first. Most people haven't heard a clean 40 Hz let alone 20 Hz in their environment. 20 Hz is not heard, hardly so it is felt and it requires some healthy output to be perceived .. at 60 dB of SPL, 20 Hz is so faint as to not be perceived by most people's ears although your walls will likely rattle and things will shake. The problem is compounded by the fact that many subwoofers distort a lot when asked to reproduce 20 Hz at realistic output say 90 dB, > 20 % THD is not uncommon.. It is not rare for some celebrated subs, to output a lot of 60 Hz when asked to reproduce 20 Hz at say 100 dB you would find some serious 60 Hz component at 70 dB SPL which is easily heard. The better subs don't and sound strangely enough at first less "bassy" .. It takes time to understand that and notice the improvement in FR almost everywhere .. to arrive at the integration will test the patience of many audiophiles
The problems are multiple and usually the audiophile tackling subwoofer integration gets to a point where the trade-offs are not worth the results, especially when the person eschew DSP. DSp is not a panacea, not a cure-all but in the realm of subwoofer to main integration DSP is the best tool there is.
O.T.
I have to stop writing , perhaps later. For now we are bracing ourselves.. waiting to suffer from (or hopefully not) the fury of a Cat 4 hurricane moving very slowly ... the South peninsula Haiti, has already being hit with some other are waiting ... It seems to move a little bit of our coast but part of .. We'll see... Discussing with you guys takes the worry off my mind ...
Best wishes FrantzM! As for your sub discussions...i have always enjoyed reading and re-reading them...thanks. In my own limited experience, i find much truth in my own time with 3 Velodynes...which started in 1993...continued to the DD18 around 6 years ago and now the current DD18+.
Mark Seaton
WBF Technical Expert (Speaker & Acoustics)
Thank you for hunting through things in their current state. The current info has only been up a matter of days and will be added to significantly over the coming week and month.
I'd be curious if the designers of your preamp and amplifiers don't think they could integrate a simple high pass filter without significantly compromising the performance. The passive networks needed to create the filtering at speaker level, while still fully analog, have their own limits of linearity, interact significantly with the speaker's load, and will even change their interaction with big dynamics. For many systems, the best high pass filter is the acoustic one created by an appropriately sized sealed box... Which I suspect is the way your MM7's operate.
To be clear, I'm largely agnostic on the methods of executing a crossover... so long as it works in an objective manner and a desirable result is had.
Hi
IN our hobby it is difficult to escape dogmas and declaration of faith. The reality is that Integration of subs with mains require flexibility. Nothing is as flexible as digital filters. Analog filters are bound to do much more harms than digital down low ... Repeating down low. I could add everywhere but ... let's leave that fight for another time
There is nothing added in term of circuitry for the Devialet or other Digital DSP to do their things, just processing and in the big scheme of things audio is a low bandwidth application wich is handled with aplomb with modern (and some last century too ) processors.
INtegration means that sometime you have to curtail the top end of the subwoofer response . IOW make sure it doesn't play over a certain frequecy range , many subwoofers do ... so while we concentrate usually on the low pass we forget the high pass. in several instances some subwoofer play loudly up to 200 Hz with often a very jagged and irregular repsonse adding much "muck" to the main response with the resulting "slow" muddy and lack of definition... and that is putting aside the intrinsic quality of the sub in the region of interest that is <50 Hz or so ...
there are many professions of faith concerning the best approach and 4 towers is good given a dedicated and well treated room and luck.
Professions of faith is a rather appropriate term. I prefer to pull back a bit from exactly how a task is achieved, and rather understand what the task and end goal. There are many ways to attack a problem, and certainly more than one good solution. One solution will not fit every application or system. I'm certainly very comfortable using DSP and various response correction technologies, but there's no reason to assume there aren't other ways to come to the similar result.
The one tool needed to step beyond educated guessing in all cases is a microphone. Without knowing what real hurdles have been created with placement and response of speakers and/or subwoofers, you can't come up with a workable solution. There are more than a few cases where you can certainly overlay a subwoofer on top of the natural roll off of a speaker in a room. Quite often the bigger hurdle is making sure room modes don't create a peak in response from the speakers well below the intended crossover or below the expected roll off of the speaker, where you can have excessive peaks or even cancellation when the speaker doesn't behave as assumed or expected. While not as simple to set up and not as inherently flexible, there's no reason an analog solution can't be had. The question to ask is always does the DSP based tool add more or fix more significant problems than it might theoretically compromise.
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