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Where 2 sit audio quiz

Ok folks, don't take this too seriously now!

It's cold and cloudy here in Wisconsin and I'm bored out of my skull.

I've been messing around with different seating positions and trying to form a pattern between measured results and audible results.
I thought it might be interesting to put up measured results at 3 widely varying seating positions, and see if anyone could suggest ideas on a range of different issues. There's a $1 Million cash prize for whoever get's it right, redeemable 11/22/2064

First the setup:
Meter used is the RS digital set to slow response and C weighted.
Test tones from Rives CD 2
The Rives CD say's to use tracks 32 - 62 which are compensated for the non-linearity of the RS analogue meter. It doesn't say what to use for the digital meter, so I tried both, and the most consistent seemed to be tracks 1-31.
Anyway, the numbers are more indicative than they are absolute. If I need to re-do the test using tracks 32+ then so be it.
I used 3 different 'practical' seating locations at 12', 17' and 20.5' from the speakers.
The 20.5' position is up against the wall, which is central on a large un-draped window (a clue perhaps.. [14'x 4' approx window dimension]). I'm showing the 3 sets of results in tabular form (wasn't bored enough to bother making a graph).
Also, I'm not saying at this point which reading relates to which seating position....(perhaps the SPL level will provide the answer?)

Speakers are Maggie 3.6R's, amps are Cary V12 Mono's with ARC LS15.
I thought I would have to adjust the preamp gain at the farthest position, but it didn't require it, so all 3 positions are measured using the same volume setting on the LS15 preamp.
Questions that spring to mind....(add more if you wish).
From the results shown at http://thenaturalshopper.com/audiohell.htm

1 - which position would seem to suggest the best sonics
2 - what do the readings say about room layout and frequency response
3 - what do they indicate as far as equipment selection(speakers) for the particular room layout (example - insufficient bass response at any position, harsh treble response, or whatever?)
4 - which position do you thinks is the 12', 17' and 20.5' seating position
5 - given that the spl's are almost identical at higher frequencies, what does that say about the room layout. (given that there is a 8.5' difference between the closest and farthest seat position, shouldn't one of the columns show a consistent reduction in SPL?).
6 - what does all of this say about people from Wisconsin

What the heck!

Rooze
128x128rooze
rives
953 posts
 
1. I won't comment yet--I want to hear a few others first
2. Same as #1, with the exception of the fact that I don't have an answer.
3. Says nothing in terms of equipment
4. Same as #1, except I do have an answer
5. This is normal and what I really wanted to comment on. Only frequencies below 500 Hz are really effected by positon unless there is some significant non-uniformity in the room--say for example you have first point of reflection absorbed at one positon but not the other--then you would see a difference in the HF response. Otherwise, the higher frequencies shouldn't change significantly.
6. You really are a bunch of Cheese Heads. Go Hawkeyes!! (we play Wisconsin next week)
rooze's avatar
rooze OP
580 posts
 
C'mon Rives get off the fence...LOL
sean
6,231 posts
 
I'm not responding until Rives posts his answers. Then i'll let him know if he is right : )

The rankings below are rated from best to worst in descending order.

Broadband frequency response linearity

1) C
2) A
3) B ( WAY behind the others )

Most solid, even & extended low frequency response ( hardest to achieve )

1) C
2) A
3) B ( WAY behind the others )

Highest average broadband spl*

1) C
2) A
3) B

Obviously, the one to go with is "C" as it offers the most linear frequency response, smoothest and most extended bass response and the highest broadband sensitity.

As to your other questions, i know nothing about everything : )

The one suggestion / comment that i would make is that you need to work on your room acoustics. My thoughts are that the first place to start would be with damping ( NOT diffracting ) the primary points of reflection. Since the frequencies that seem to be the most troublesome here are relatively high in nature, you don't really need anything that is real thick or offers extended low frequency coverage. You can probably get by with using some relatively thin "acoustic foam" that is properly placed. This should tame the "hot" upper mids and treble response that you are experiencing without really toying with any other part of the audible spectrum. This would improve linearity even further and help to level out the otherwise "hot" and potentially highly sibilant upper mids / lower treble that you are probably dealing with. Sean
>

* If we limit bandwidth from 40 Hz and up, "A" offers the highest average spl of the three. Even with bandwidth limiting though, "A" does not offer the solidity or evenness in low frequency response that "C" does. As such, "C" is still the clear winner even after trying to compensate for the lack of extension in "A" and "B".
rooze's avatar
rooze OP
580 posts
 
Hey Sean, your suggestions about dealing with 'audible' issues such as hot upper mids are consistant with what I'm hearing. I should have said that I'm using the 3.6's without any tweeter attenuation, and I think that has certainly raised the higher frequency output. So re-inserting the 1.2ohm resistor would probably tame the treble response somewhat, to the detriment of transparency, as seems to be the case.
I wondered if you had an opinion on which of the 3 locations is the 12, 17 and 20.5 location?....or is that an unfair question given the parameters listed?

Lastly, would you say that the combination of speaker and room could offer an even lower output in terms of absolute low frequency extension, or perhaps a higher spl on the 20, 25 and 31.5Hz readings. I've put quite a bit of time into extracting any kind of output at 25hz and below, including placement, some diffraction materials, custom, stands, marble supports under stands, and the Cardas x-over cable kit. Would you say that's about as low as they'll go, or do you think there is more room for noticeable low frequency output? That might be a question for Tireguy perhaps, but I would welcome any input.

Rooze
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