[JohnR]

You used the term "speaker correction" earlier, so I might assume that you understand the difference?

[roscoeiii]

You used the term "speaker correction" earlier, so I might assume that you understand the difference?

Honestly,  I think I have been using correction and calibration pretty interchangeably.  With the exception that perhaps calibration could change the speaker response in whatever way a user wanted, not just to make up for shortcomings in measurements, relative to what a user thinks an ideal response looks like (which would be " correction").

[JohnR]

Um, OK I guess this kinda gets back to the question of what "DSP" means... to me it's any kind of processing, done to any kind of signal, digitally. (And I think that's a reasonable definition.) The distinction that I was trying point out was between "speaker" and "room", not between "correction" and "calibration." If we can stick with the former, then yes, the DEQX can do both, depending on what exactly you define as "room correction," but since you earlier referred to speaker correction then I assume you understand the distinction between in-room measurements and (pseudo) anechoic measurements and therefore what can be calibrated/corrected etc with each.

[JohnR]

oops, accidental post instead of modify.

[roscoeiii]

Um, OK I guess this kinda gets back to the question of what "DSP" means... to me it's any kind of processing, done to any kind of signal, digitally. (And I think that's a reasonable definition.) The distinction that I was trying point out was between "speaker" and "room", not between "correction" and "calibration." If we can stick with the former, then yes, the DEQX can do both, depending on what exactly you define as "room correction," but since you earlier referred to speaker correction then I assume you understand the distinction between in-room measurements and (pseudo) anechoic measurements and therefore what can be calibrated/corrected etc with each.

If you look at the DEQX, you'll see that measurements and correction/calibration are done in 2 steps.  First,  the speaker is measured at 1m and things like phase, frequency response (above the bass, in freqs which the room plays a smaller role) , time coherence of the drivers, etc are measured and corrected. Step 2 is measuring from the listening position to adjust for the effects of the room.

[JohnR]

Yes, I know that...   

[roscoeiii]

Yes, I know that...   

OK, well let's just get back to the main topic here...

[jtwrace]

OK, well let's just get back to the main topic here...

Since John will not post it I will.  He surely knows what he's talking about in this realm.  Have you seen his articles here? 
 

If you look at the DEQX, you'll see that measurements and correction/calibration are done in 2 steps.  First,  the speaker is measured at 1m and things like phase, frequency response (above the bass, in freqs which the room plays a smaller role) , time coherence of the drivers, etc are measured and corrected. Step 2 is measuring from the listening position to adjust for the effects of the room.

 

[JohnR]

Um, I think it's really just a question of defining the issue being addressed and how it's being addressed. "DSP" is an overly broad term, and really so is "room correction" (since there are so many ways of doing it, with varying results). The false (IMO) dichotomy between processing (of whatever kind) and room treatment deserves to be exposed though, they just don't do the same thing.

[jtwrace]

The false (IMO) dichotomy between processing (of whatever kind) and room treatment deserves to be exposed though, they just don't do the same thing.

Yes, very true!

I suppose I should shut up now?

Never. 

[roscoeiii]

+1 to what jtwrace said.

[Tomy2Tone]

Um, I think it's really just a question of defining the issue being addressed and how it's being addressed. "DSP" is an overly broad term, and really so is "room correction" (since there are so many ways of doing it, with varying results). The false (IMO) dichotomy between processing (of whatever kind) and room treatment deserves to be exposed though, they just don't do the same thing.

Maybe this could be a teachable moment?

Or maybe a reference for which I could read in regards to what room correction really is and how its defined and by what methods it's achieved. This way maybe I could effectively communicate what I'm trying to say. Thanks!

[JohnR]

I'm not really sure that the concept of room correction is well defined. When you look at an anechoic speaker response, that is well defined. When you put a loudspeaker into a space, it's response in 3D space actually becomes a lot more important (power response). A well-behaved loudspeaker (per Toole) will generate a measureable response. It's typically characterized into two or three frequency regions: modal, transition, and diffusion. It's not unreasonable to think that naive inversion of the amplitude response under those conditions might not be such a great idea. What is a good idea depends on who you ask. Dirac would say that you can perform a sophisticated analysis of measurements made across the listening area and perform a time correction of the first couple of ms, which is essentially loudspeaker correction, and amplitude correction based on (in my words) a "do no harm" policy. DEQX would say that you first correct the anechoic (amplitude and phase) response of the speaker (with suitable measurements) and only then do you perform (minimum phase) amplitude adjustments based on in-room measurements. But neither of these are JUST doing room correction.

[RichardS]

Hi Tommy
To answer your original question (just one audiophile's opinion, of course):

-Do you use a type of dsp and if so why and what are its effects?
     Yes. I use Tact equipment, both preamp and amp, originally stock and now modified. My system also includes amps and preamps (Devialet, Auralic, etc) where I don't use room correction, as an alternative to the Tact stuff -- I just need to change out the speaker cables. Both systems sound great, but the Tact stuff provides more detail and dynamics with cleaner bass. I'm also very familiar with a friend's system with DEQX, which is similar in effect.
The Tact system, esp w/ mods, and even more so with corner subs, opens up the mids, expands the soundstage and evens out lumpy bass (and I have a reasonable good 10'x16'x24' room). The Tact time aligns the bass to the rest as well. At one time I used the Tact RC preamp with other amps (Bel Canto, Gamut) but I preferred the sound using the Tact amp, keeping the signal in the digital domain all the way to the speakers.

-Are you against any type of dsp being involved in the signal and if so why?
     No. Though there are trade-offs. The Devialet alone is warmer with more body, but you can dial in different frequency curves as you wish with the Tact, with really minimal losses of transparency. The Devialet, and the Auralic, treble is slightly more natural, but the bass is muddier. Horses for courses of course...

-Do you use both room treatments and dsp? Or just one or the other?
     I use corner bass traps and ceiling-corner and first reflection diffusers. At one time I had a room full of  treatments, but WAF encouraged me to discard much of this. IMO, though not doing the same thing, the room correction nevertheless had as significant a positive impact.

[richidoo]

I have used Tact room correction and enjoyed the effect in the bass freqs, clean strong powerful bass in the sweet spot. But in other room locations the bass sounded worse. In the sweet spot my head feel weird from the phase adjustments or whatever it was doing. I couldn't take it long term. Other people I know using tact didn't have this problem.

I agree with those who argue that the cause of the problem is uncontrolled reflections in the room, and consequently no change to the electronic signal can affect the inherent resonances and reverb times particular to a room. Only physcial treatments can treat the cause. But too much treatment is alspo a problem because people like the sound of a lively room if the bass modes are controlled. Floyd Tooles book has a lot of good practical info about what sounds good and what works.

I'm curious to try DBA (Dual Bass Array,) aka CABS (Controlled Acoustic Bass System) that Scotty turned me onto. Bass drivers on front and rear walls spaced to create a single planar wave and avoid lateral and vertical modes. Front array launches and the rear array cancels the planar waves minimizing room modes forming. No physical room treatments needed, only a simple arithmetic DSP providing time delay and level.