Why do so many automatic configuration systems set centers/rears to "large"? (1 Viewer)

[Bobby T]

Kevin very slick. I noticed from the avs forum that we have the same DVD player.

 

[Andrew Pratt]

FYI here's what Jeff from S-N just posted on our Sherwood-Newcastle board

 

[LanceJ]

Er, that's a bit confusing.....I think. I can see where it is informative for some people to know more about their speakers' bass reproduction characteristics, but for others I'm not sure this makes the system set-up process easier.

 

[Kevin C Brown]

Yeah, why couldn't it just do all that automatically? And then if a user wants to override anything, they could just do it after the autocal?

 

[Bobby T]

I understand what he's saying, and I agree it should be part of the auto setup.

 

[LanceJ]

I have to be honest: as much as I like surround sound for movies and music, I find myself daydreaming more and more about my future stereo-only secondary system.

I've been doing this for years anyway, but with all the fuss that surround needs to sound even 75% right, the thought of dealing with that 2.0 rig slowly gets more attractive. Just two floorstanders, an amp & a preamp and a nice CD player & turntable. I'm not sure yet about including a hi-res digital source - the title selection is awful for us rock/pop fans.

I'll always have a surround system, but the 2.0 system will be my old-skool/easy-breezy system to listen to.

 

[LanceJ]

This sort of fits into this thread:

Complexity causes 50% of product returns: scientist

from the article....
While YPAO, MCACC, etc may not be perfect, they should really help to reduce the amount of stress experienced by many of their owners (and I bet y'all thought I was just being an old fart when I posted that link to that barebones-but-still-popular 1976 Advent receiver in another thread here ).

 

[Andrew Pratt]

Here's the whole thread that Jeff's being posting to. It might help explain where he's coming from with his comments about setup.

 

[Brian L]

I have done exactly that Lance, but could not resist the temptation to f*ck it up and make it a 2.1 system, complete with ICBM and BFD!

Having said that, I love listening to this rig,, and have bought lots of redbook CD's since.

FTR, it consists of:

Marantz SR96 AVR, set to 2CH mode
Rega P2 w/Shure M97xe cart, NAD PP2 Phono Preamp
Rotel 1072 CD Player (HDCD capable)
Pioneer 45a Uni-Player
Pioneer 509 CD-R Deck
Behringer Feedback Destroyer
Outlaw ICBM
Panamax power center (not sure which model)
NHT AZ loudspeakers (previously used KEF Q10s, then NHT SB3's)
Klipsch SW8 II Sub

FWIW, a lot of this gear is cast-off stuff from my HT rig....couldn't see it just gathering dust, could I????

Brian

 

[Bobby T]

Lance you could go way old school with tube amps and an analog tuner. And try to get gear with analog readouts instead of digitl displays. It would be cool to see tubes glowing and needles bouncing. Over on the Klipsch forum they have a dedicated 2 channel area.

 

[Kevin C Brown]

BGL- I was going to ask if you had a record player! IMO, that's the best way to experience two channel. For whatever reason, I've also been listening to more vinyl lately. Well ... I still have a lot of older stuff where I never bothered to get the CDs, or they actually never came out on CD ...

 

[Brian L]

I am sure many will scoff, but the best sound I can get out of the 2CH rig is when its playing vinyl.

I have a mint, original copy of Dire Straits "Love Over Gold" which is without a doubt the best sound I have ever heard. I have also picked up some of the Classic Records 200g Zeppelin titles, a couple AC/DC titles, and a few others.

All of it is to die for. It may not be accurate, but it sounds very, very good.

Next step is to add some tubes to the mix!

Brian

 

[LanceJ]

Actually, as some scientific studies have shown, flat response systems can be rather un-fun to listen to (usually the participants complained the music was too bright or sterile).

 

[Bobby T]

Lance you can actually buy new tube amps, although they may not be cheap. Also Parts Express sales tubes for not a lot of money. Sound aside, tube amps look way cool when they get glowing. Needles bouncing on analog gear is also cool.

Back to the original topic. Have we made any more progress finding out why the auto calibration sets speakers to large?

 

[LanceJ]

So far, none of the receiver manufacturers I asked - Pioneer, Denon or Yamaha - have been willing to explain this & I don't understand why (trade secrets or something?).

 

[JeremyErwin]

I suppose you could search the patent office's files for more details. Not every piece of intellectual property is a trade secret...

The difference between small and large may lie in the slope of the frequency response, and not merely in -3db response.

I found this old Stereophile interview with Ken Kreisel.

source

Now, let us suppose that you had speakers that were flat down to 35 Hz. They can't reproduce the entire range, but if you used the THX crossover design, the summed result of subwoofer and "satellite" would be a pronounced hump in the bass, right around 80 Hz.

And in case you're wondering, yes, M&K has a whole page of THX loundspeakers with frequency responses of 80 Hz--20 kHz. There's no sign of the "flat to one octave below the crossover frequency" recommendation.

(I'm not advocating THX. It's just one solution to the problem at hand-- and if sufficiently reverse engineered, may give us some clues to how a bass management system can be designed.)

Suppose that a automatic configuration program "misclassifies" a particular speaker as "large". Without measurements, how can we be sure that this really is a misclassification?

 

[Kevin C Brown]

THX is different. For THX systems, the roll off of the speaker is designed to add to the crossover slope. Hence, a THX speaker *has* to be -3 dB at 80 Hz. For non THX systems, to guarentee a flat response through the crossover, the low extension of the speaker needs to be 1/2 or 1 full octave below the crossover freq.

 

[Brian L]

I continue to struggle with the "One Octave Below" suggestion KCB...

My NAD 762 has a 24/12 crossover. It is NOT a THX design, but uses the same crossover slope. It does have selectable crossover frequencies. If I go with 80 hertz, would you still opt for a loudspeaker that goes down to 40 Hertz with that? Does not seem right to me if you want the speakers roll off and crossover to sum to 24dB.

And how many AVR's have a HP that is NOT 12dB/oct? Most follow the THX settings, yet most users do NOT use main channels that have an 80 hertz -3dB point.

Now lets confuse matters with the ICBM. HP is given as 12dB/oct. LP can also be 12 or 36. But they call 36 their THX mode for THX subs. What's up with that? If THX dictum calls for 12HP/24LP, why does Outlaw think that they need a 36dB LP?

Some day this will all jell in my mind

Brian

 

[JeremyErwin]

I've been looking through old sound and vision lab results-- haven't found one that wasn't a 24/12, though perhaps the techies really are not looking for one.

 

[Kevin C Brown]

THX is 24dB/octave on both sides. Most non-THX xovers are 24/12 high pass/low pass.

So ... at 80 Hz we get:

Non-THX: 24dB/80 Hz and 12 dB/40 Hz are the same so you get flat freq response through the crossover ... if the speaker's slope is far enough away.

THX: 24/80 is not equal to 24/40 so you need the speaker's low freq roll off to also be 24/40 which adding together is 12/40 which equals 24/80 again. Be careful, they are not like fractions.

That's how I think about it, anyways...