Speaker/Room calibration

[NorthStar]

They're still looking for Jimmy Hoffa.....

Lee

-----Wow, what an accute sense of humor Lee!

_____________________

* I am not 100% positively certain but I believe that Bruce has some spikes under.

 

[Bruce B]

Good one!!

I put the spikes back in and set them on Wave Kinetics 2NS pucks. You can actually slide the speakers short distances ( <1' ) with these things.

I will be posting more graphs and do a follow-up. I've decided on 2 subs and more room treatments.

 

[NorthStar]

---Two subs is good Bruce. ...What kind of Room EQ do you use? ...Besides room treatments.

Perhaps you did mention in the past, but I just don't remember.
It is one of those threads; where time and perfection are totally irrelative.

 

[Bruce B]

---Two subs is good Bruce. ...What kind of Room EQ do you use? ...Besides room treatments.

Perhaps you did mention in the past, but I just don't remember.
It is one of those threads; where time and perfection are totally irrelative.

I feel with a purpose built room, positioning, speaker controls and extra subs are all you need. The configuration of my system would prohibit the use of DSP at this time.

 

[rbbert]

You do have pretty flexible EQ for the woofers, though, don't you?

 

[FrantzM]

I would still say this has more to do with positioning. As the graph appears on post #40, I almost got rid of the 125Hz null just by moving my speakers/listening position.

many forget the importance of the Listening Position .. Speakers Reponse in a room is function of the listening position... in my expereince it is best to sit away from boundaries, same with speakers ...

 

[edorr]

I believe he mentioned to me he is using the wave kinetics 2NS, but I am not 100% sure.

http://www.bluelightaudio.com/products/wave-kinetics/wave-kinetics-2ns-loudspeaker-interface-system/

Oops. Way behind the curve I now see.

 

[edorr]

You do have pretty flexible EQ for the woofers, though, don't you?

The MM3's do not have build in EQ. You can change the X-over point, and make some other adjustments, but very limited overall.

 

[edorr]

I feel with a purpose built room, positioning, speaker controls and extra subs are all you need. The configuration of my system would prohibit the use of DSP at this time.

I'm went the opposite position. I sold 2 x JL 113, and I use Trinnov DRC instead. Of course, my room is not nearly as good as your studio, so working with a completely different set of parameters / contraints.

 

[microstrip]

Good one!!

I put the spikes back in and set them on Wave Kinetics 2NS pucks. You can actually slide the speakers short distances ( <1' ) with these things.

I will be posting more graphs and do a follow-up. I've decided on 2 subs and more room treatments.

Bruce,

Are you considering adding some waterfall type graphs? I am currently particularly interested in decay modes.

 

[theguesswho]

Bruce said, "I feel with a purpose built room, positioning, speaker controls and extra subs are all you need. The configuration of my system would prohibit the use of DSP at this time."

I can understand the need to further correct your room, as I had correctly surmised early on that it was indeed the room. This was proven when Bruce moved his speakers from one end to the other. It was confirmed by his wonderful graph which he displayed in one of the posts.

Bruce why two more subs? I don't understand why they are needed? You have bass down to 8hz with a completly flat response, so why the additional electronics with associated noise and electronic artifacts?

After the limitations of broadband EQ for high definition audio reproduction became known in the 1970s, the audiophile world concentrated on building or correcting the room to address frequency response nulls and peaks and leaving the audio signal as "pure" as possible. Any electronic room acoustic correction will add noise and distortion to a system. For movies it is not much of a problem, for critical music listening on highly resolving equipment it can be deadly. This is the reason I am sure, why Bruce does not want to use EQ.
He needs a highly resolving system and adding any additional electronics destroys that purity of essence.

Wendell

 

[Bruce B]

Bruce why two more subs? I don't understand why they are needed? You have bass down to 8hz with a completly flat response, so why the additional electronics with associated noise and electronic artifacts?
Wendell

The 2 bass subs are not to extend the bass, but to fix an irregularities between 60 and 200Hz that are caused by room nulls.

 

[microstrip]

The 2 bass subs are not to extend the bass, but to fix an irregularities between 60 and 200Hz that are caused by room nulls.

I am trying a similar approach with the Aida's. Although they extend their FR to 18 Hz in my long room, I need two subs to fill a room null between 30 and 40 Hz.

 

[FrantzM]

I am trying a similar approach with the Aida's. Although they extend their FR to 18 Hz in my long room, I need two subs to fill a room null between 30 and 40 Hz.

Do try an asymetric sub position.. in the front plane... Just try one sub in the corner and another on the opposite wall... in the front plane ... Subs must have phase control ...

 

[NorthStar]

---Someone here tell me if I'm wrong or right.

* I believe it's best to use the same polarity (phase) when using multiple subwoofers.

 

[microstrip]

Do try an asymetric sub position.. in the front plane... Just try one sub in the corner and another on the opposite wall... in the front plane ... Subs must have phase control ...

FrantzM,

The one if the opposite wall will also be in the opposite corner? Any preference for the height? I will consider it - even because it will be a position where they will interact minimally from a visual point of view.

The Martin Logan Descents are temporary - the final version will probably include in wall custom made subwoofers.

 

[DonH50]

---Someone here tell me if I'm wrong or right.

* I believe it's best to use the same polarity (phase) when using multiple subwoofers.

The polarity probably does not matter but the actual phase depends greatly upon where the subn is in relation to the listener, the walls, and the frequency(ies) yuo are trying to compensate. The principle behind using multiple subs in a HT environment is primarily to smooth out the frequency response by providing another signal source. You want the second (third, fourth, whatever) source to attenuate peaks and raise nulls by combining at the listening position in the proper phase to compensate the proper frequencies. That depends upon distance and frequency. There is no simple answer.

 

[NorthStar]

The polarity probably does not matter but the actual phase depends greatly upon where the subn is in relation to the listener, the walls, and the frequency(ies) yuo are trying to compensate. The principle behind using multiple subs in a HT environment is primarily to smooth out the frequency response by providing another signal source. You want the second (third, fourth, whatever) source to attenuate peaks and raise nulls by combining at the listening position in the proper phase to compensate the proper frequencies. That depends upon distance and frequency. There is no simple answer.

-----Thanx Don.

Let say that you have five subwoofers total:
- Two of them are positioned at the front of the room near the two front corners and equidistant to the main prime listening position.
- Two more are slightly behind the main listening position, at the sides, and again both equidistant to the main listening position.
- The fifth one is behind the main listening position, dead center, and at the same distance as the two side ones. And that fifth one is strictly for the LFE channel, that's it.

Should the Phase control of each sub (four of them are the exact same subs by the way, four 12 inchers; only the one behind the couch is different, and much bigger; an 18 incher) be set at the same Phase position? ...Before you start measuring, balancing, accentuating, attenuating, ... EQuing.

And of course it is for a multichannel surround sound setup, like for movies.

 

[DonH50]

That all depends on what sort of EQ system you have. If it can independently adjust the phase of each sub then you can set them all the same. If not, or if you are doing it manually, you will have tok play around and measure or listen. My subs have a continuous phase control, one reason I like them.

If all subs are equidistant from the listening position then the phase should be the same for all. In the room, assuming you want the smotthest response, you will almost certainly have to adjust them, perhaps in front and rear pairs and then the LFE, to optimize the reponse in your room.

 

[NorthStar]

---Ok, the two front subs are further away than the two side and rear ones.

And the Auto Room EQ is Audyssey Pro based on Audyssey MultEQ XT32.

Furthermore, the two front ones are strictly enhancing the bass of your two front Left and Right loudspeakers, respectively.
And the two side subs are enhancing the two side Left and Right surround speakers strictly and respectively.
Only the rear one is for the LFE channel.