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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
rooze's avatar
rooze OP
636 posts
 
Sean, sorry I just posted my last response as you were writing yours, so didn't see/comment on your last observations. What you say makes good sense, particularly that most of the issues concern higher frequency brightness and sibilance effects.
I'm intrigued to understand more as to what is causing the drop in SPL at the midway (17') point. Could it be that the 17' point is actually the more neutral place and therefore the 'best' place sonically?....perhaps what I'm hearing at the 12 and 20' points is 'boom' and 'refelections' for want of better terms. The sound is good at the 17 point, but just isn't warm enough with the absence of the lower frequencies...
Believe me when I say that as far as trial and error goes, I've worked bloody hard sliding those blasted marble slabs around!....I think where the speakers are now gives me the best low frequency extension and depending on the final choice of listening position, either a wide open soundstage (far position), or an envelopling, detailed and intimate sounding presentation (near Position).

Thanks again for helping me understand what is going on and help in exploring my options.

Rooze
newbee
4,767 posts
 
Rooze, I'll have to admit that I have never worked with a room this size, let alone a room of this size with panel speakers. For what its worth I would opt for the best positioning for resolution and soundstage and supplement the bottom end with a fast pair of subs located in an area which will give you flat bass to 20 hz. How's that for a cop out! By the way have you checked out other room set up systems, such as Cardas. If not, you can read about this and others in the FAQ's at the Audio Asylum site. I'm not sure how you came by your listening seat positioning, but did you try the 14 to 15 ft area. I've often found some of my best bass reinforcement when the speakers and the listening position are around 25% of the room dimension (which in your case would be 7ft for speakers and seat). Have fun - good tuning takes a long time and you should take your time do it. Its a lot more than just good measured frequency response.
sean
6,231 posts
 
While i didn't present all of the figures involved in coming up with the conclusions that i did, C and A are quite close when looking at the big picture with B being off in left field ( no offense to left fielders : ) If going strictly by the figures though, C is the winner. Then again, facts & figures never factor in personal preference.

Newbee brings up some VERY valid points regarding low frequency response and output levels. With a room this large, you really should be looking at an active crossover and some subs. I would only go this route AFTER you feel comfortable that you've gotten everything dialed in with what you already have. Otherwise, you'll be running back and forth between the mains and the subs and it will only get more confusing. Sean
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rives
953 posts
 
Sean:

I didn't say rooms don't have an effect above 500 Hz--that would be REALLY wrong. I did say that positioning (both listener and speakers) has little effect above 500 Hz. Now that's not true in all rooms, but a room that is reasonably well balanced it is true. If high frequencies are tipped up, that will be true throughout most of the room--unless you are right up against one area that is heavily absorbing, but then this wouldn't be a well balanced room. In the bass region however there are peaks and nulls and they vary greatly by location.
sean
6,231 posts
 
Rives: I'm sorry if i misinterpreted your comments, but i still don't agree with your clarification presented here. Due to the fact that all drivers "beam" or alter their radiation pattern as frequency is raised, one is bound to encounter varying frequency responses as speaker position and / or seated listening positions are altered. This can easily be measured outdoors where there are "minimal" room boundaries to cancel / reinforce / reflect the signals being produced and measured.

As further evidence, this can also be seen in just about any "decent" speaker review as the frequency response is altered as one changes the axis that one is listening on. Since distance changes the listening axis ( speakers don't rotate to accomodate seating distance ), you are bound to have quantifiable* differences in frequency response linearity. Sean
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* don't know if this is the most appropriate terminology, but it sure sounds impressive : )
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