Where 2 sit audio quiz

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
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* 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".

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

Here's a hint, Go to the free simulator on our website:
the Room Simulator . Now I don't even have to post my answers:) You will also note, that the position as Rooze found, has little or no affect on frequencies above 500 Hz.

Have I missed something? I looked at your calculations and on the surface C sounds best but for what purpose I don't know. Your speakers could be placed in the center of the room immediatly adjacent to each other and actually sound (in audiophile terms) like crap. Why not give us the dimensions of your room and the physical location of the speakers so we can make meaningful comments. Re the bass - I think C is misleading - I think your low bass in C is nothing more than a room node and A may be in a bit of a suck out. PS I always fail tests.

Rooze: I would not insert a resistor into the tweeter section until you address the primary points of reflection. If you do that and things are still too "hot" sounding, then go the resistor approach.

As far as bass goes, Newbee has a point. That is, you need to configure the speakers AND your seated listening position taking room nodes into account. Getting the speakers positioned is one thing but then throwing that away with a poor listening position is all too common. Anybody that thinks that you can't take the room into account and obtain optimum results is fooling themselves.

Having said that, diffusion / diffraction is typically only good at mid to higher frequencies. Bass is a completely different animal and far trickier to work with. I can't really make suggestions based on the information that i have here. The one suggestion that i would make would be to pick up some books on acoustics and read, read, read.

Newbee: Your comments about room nodes is kind of "there, but not there". Everything that you hear is a combo of directly radiated sound and reflections / room nodes. There is no way to avoid this so the smart people learn how to tame and / or incorporate them into the response that you hear at the seated listening position. It is impossible to achieve linear response at multiple positions spread over a wide area.

Rives: I can't agree with your comments regarding rooms not really affecting anything above appr 500 Hz or so. The measurements that Rooze provided support my beliefs and experiences. While a lot of this will vary from room to room and speaker to speaker, making such a "generic" statement put you out on a limb. Luckily, i have a saw and a ladder and i'm going to get you down from there : )

Let's look at the variances above the cut-off frequency that you mentioned i.e. 500 Hz. Cutting you some slack, we'll double that and look at 1 KHz and above. I'll list the center frequency and the amount of variance from the highest reading to the lowest reading. This will demonstrate how much room loading can affect the sonic perspective at these frequencies.

1KHz - 13 dB's variance

1.25 KHZ - 9 dB's variance

1.6 KHz - 11 dB's

2 KHz - 6 dB's

2.5 KHz - 5 dB's

3.15 KHz - 5 dB's

4 KHz - 5 dB's

5 KHz - 10 dB's

6.3 KHz - 5 dB's

8 KHz - 10 dB's

10 KHz - 7 dB's

12.5 KHz - 6 dB's

As one can see, there are major divergences depending on room nodes / reflections regardless of frequency. To be fair to Rives, much of this has to do with the type of speakers being used. While Maggie's are not "oddball" or uncommon speakers, they do present a very different type of installation challenge than what most "front firing boxes" would. As such, one can not make sweeping generalizations without expecting some type of variance from installation to installation. Since i have every type of speaker known to man ( large towers, dipole's, omni's, mini-monitors and horns ), it is easy to see why i might have the outlook that i do whereas Rives has probably worked with more conventional designs most of the time.

As a side note, this is the reason that i don't respond to a lot of threads i.e. too much room for interpretation due to variables and not enough information presented. On top of that, i hope that some folks realize that "spec's" can be interpreted usefully. That is, IF one knows how to understand the data provided and that data was obtained in an accurate manner.

Having said that, i worked with the information presented here. I took into into consideration that the speakers are where they are and that Rooze has ( hopefully ) done his best to get them in the right spot. If such is not the case, then speaker placement should be done first and then one can calculate proper placement for room treatments from there. Not all rooms should be treated identically or following set formulas as the radiation pattern of the speakers to be used will alter what is required. As such, you can set up a room for one set of speakers and end up requiring a different configuration when you change speakers. Sean
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