[youngho]

Howdy!

Yet another inquiry: if one has more than one subwoofer and intends to use parametric equalization, should one measure and equalize each one separately or measure and equalize them as a group? I had been covetous of the Yamaha Z9 with its two separate parametric equalizers for its two separate subwoofer outputs, but maybe I shouldn't be.

I had used the one-band parametric equalizer in my Infinity speakers separately, but thinking about the Harman paper, I realized that mode cancellation might result in unintentional nulls or peaks when the two equalized speakers are then played together. I had never bothered to re-measure the summed response but will have to do so this weekend.

Since I am in a significantly assymmetric room, this will likely result in uneven and different bass response from each speaker, but paradoxically the total response will be more even.

Am I correct in my thought process?

Young-Ho

[Ethan Winer]

Young-Ho,

> should one measure and equalize each one separately or measure and equalize them as a group? <

You need to measure with both subs running, because that's how they'll be used. But you'll get the most flexibility if you EQ them separately. That said, EQ'ing one sub is tough enough, especially since you should also tweak the phase knob. Add a second sub and you now have a huge number of possible combinations!

--Ethan

[jpsartre]

You need to measure with both subs running, because that's how they'll be used. But you'll get the most flexibility if you EQ them separately. That said, EQ'ing one sub is tough enough, especially since you should also tweak the phase knob. Add a second sub and you now have a huge number of possible combinations!

--Ethan

That would be one laborious task (separate eq for each sub). I'd split the signal after eq and feed it to both amps as long as I could get my flat response. If you can't get a flat response this way, then you have to do it like Ethan said. Regardless, I'd measure with both subs playing AFTER I settled on their final location.

[youngho]

Thanks for the advice.

My main speakers are Infinity Intermezzo 4.1Ts, which each have one band of parametric EQ built in. I'm running them as large. However, they don't allow for phase adjustment, as the 12" woofers powered by 850 watts are built into the chassis of the speaker itself in a side-firing mode, so phase isn't an issue in terms of integration with the rest of the speaker.

My surrounds are the 2.6s, which also have one band of parametric EQ each, but I'm running these as small for now, so I haven't fiddled with the EQ. Whew! That would be a pain!

I will measure each 4.1T both separately and together, then use the individual graphs to estimate which speaker contributes how much to which peak in the summed response graph.

I wonder how the automatic calibration systems handle this issue and how folks with more than two subwoofers do this!

Young-Ho

[John Casler]

That said, EQ'ing one sub is tough enough, especially since you should also tweak the phase knob. Add a second sub and you now have a huge number of possible combinations!

--Ethan

I am with you on that one

Imagine what I have to deal with.  I have 4 subs, which have damping adjustability, running through 2 separate adjustable x-overs, and a R-DES equalization circuit!!!

Between placement, phasing, Low Pass Selection, damping, and 4 band digital equalization, it has been very interesting.

That said, I have some of the best bass, I have ever heard, if you consider detail, 3-D depth, Frequency Depth, Impact, and realistic sound.

But to be sure, it is only in a specific area.

[Ethan Winer]

John,

I have fabulous bass in my HT with only one Carver Sunfire subwoofer.

Yes, the bass level and quality is not identical everywhere, but it's about as close as I imagine is physically possible.

--Ethan

[John Casler]

John,

I have fabulous bass in my HT with only one Carver Sunfire subwoofer.

Yes, the bass level and quality is not identical everywhere, but it's about as close as I imagine is physically possible.

--Ethan

Ah yes, the simplicty of "singles".

My quad Sub set up is an experimentation, not a primary need for most bass requirments.

Since it is for a 2 channel "only" system, I am not concerned at all about any position other than the "listening position".

My HT has a small 10" sub sitting in the right front corner that does an excellent job too, since the rerar of the room is open to the rest of the house, causing fewer problems to deal with

Great series of posting by the way on the Audioholics site.

I think what some miss in the "equalization" scenario is that while it solves a few problems, it alters the signal

In a perfect world, it would seem more "accurate" (I always think in terms of audiophile 2 channel maximization, not foley driven HT) to take room treatment/alteration to its reasonable conclusive level "THEN" begin signal manipulation.

And obviously this "caveat" is much more important in the mids and highs, but the "order" of attack should still be observed in LF too.

I make the "distinction" between 2 channel audiophile spaces, and HT spaces, since while they share many acoustic goals, they also have "specifics" that might be more effective for them individually.

Much like some of the acoustic goals of a venue (church/auditorium/concert hall) will also be different than a 2 channel reproduction environment.

With the 6 boundaries being so much "bother", you'd think that "tent roofed" outdoor listening rooms would be all the rage

Hmmmm...  Maybe there will be a market for "Audiophile" indoor/outdoor gear

Maybe I should start looking for that "farm land" now?  Talk about an IB sub....that would really be the ticket to accurate phrasing (and phasing)

Just my opinion.

[Ethan Winer]

John,

> Great series of posting by the way on the Audioholics site <

Thanks.

> take room treatment/alteration to its reasonable conclusive level "THEN" begin signal manipulation. <

Yep.

> you'd think that "tent roofed" outdoor listening rooms would be all the rage <

Don't laugh, but lately I've been envisioning how to design a tiny little "room" not unlike those racing car simulators you see at arcades. Easy to get a good low end, and relatively easy to sound proof so you can blast your ears off and not disturb people in another room. But will the market (outside of Japan!) accept such a concept?

--Ethan

[John Casler]

 
Don't laugh, but lately I've been envisioning how to design a tiny little "room" not unlike those racing car simulators you see at arcades. Easy to get a good low end, and relatively easy to sound proof so you ...

LAUGH!!!!  I designed such a room in 1982 with intentions of marketing it, for Audiophiles who live in buildings where playing their systems at higher levels was impossible.

I wanted it to be small enough to fit in a garage, attic, large closet, or just about anywhere.  I also had designed in Isolation platform so that it didn't transmit much (if any) resonance into the floor or around the room.

I looked at prefab buildings, shipping crates and many other methods, but did not have the motivation to move it to the next level.

In many ways it was car audio at a 2 channel audiophile level.

No WAF since it was basically a single seater (two seater on the drawing board)

It certainly was fun working on it.  All my closets and spare bathrooms at one time became "anechoic chambers"

So "laugh", no, not me.  I think it's a great idea.  Like it or not, 2 channel audio is 99% of the time a single user hobby.  It was like sitting inside a pair of headphones, but with the speakers "in front" all the soundstage and depth cues were there.

Some of my experiments would have made you laugh, however.

I mean I had my spare  bathroom lined (walls, floor and ceiling) with matresses, comforters, wool and flannel blankets, as well as loads of acoustic foam.

I would go in there and listen for hours.  It was unbeleivable the depth and purity of the sound, which was unachievable  in any other room.

My ex-wife thought I was crazy

Keep me posted on the project.

[Ethan Winer]

John,

> LAUGH!!!! <

Okay, I will:



> I looked at prefab buildings, shipping crates and many other methods <

I imagine a kit made of MDF and other stuff that can be easily assembled (and disassembled). Besides audiophiles, it should appeal to people in small apartments who want to be able to mix accurately. On one hand it seems difficult to sell a bulky box, but apparently companies sell enough of those large vocal booths to make it worthwhile.

--Ethan

[ted_b]

Hey, what you guys are envisoning is this:

www.theoculas.com  

     

It's been talked about in this thread:
http://www.audiocircle.com/index.php?topic=16848.msg147325#147325

 

Ted

[Ethan Winer]

Ted,

> what you guys are envisoning is this <

Yeah, pretty much.

Since no price is given I'll assume it's really REALLY expensive. I was thinking more like a few grand. Speakers not included.

--Ethan