Try to learn REW and room treatment physics or just enjoy the music?

[Oddball]

Not mutually exclusive.

Always interested in a good therapist, but then when I hear their rates, I figure out best to bug my friends for free .

 

[phoenixdogfan]

I think you are getting some very good advice here. The R11s should in no way have that suck out from 3k to 13k, so you are either doing something wrong with the room treatments, or the speakers are defective or you have somehow inserted some kind of broad filter centered at 7k taking everything down by 15 db. (That dip is very symmetrical, so to my eyes it kind of looks like some kind of filter has somehow been inserted into the chain). I definitely find it worrying that you do have a plot with the treatments removed showing the same suck outs. I might take one or both of them outside and measure, just to see if that's somehow room related, but the KEF's should be less susceptible to room issues than most any other speaker.

Once you get that sorted out, I'd suggest you look into replacing your streamer with something like the mini-DSP Flex or SHD, both of which have Dirac Live. Dirac greatly simplifies the learning curve for a new audiophile, and provides professional level room and speaker correction which should be as good as if not better than anything that can be done with REW. Given what you already have tied up in that system, having a streamer/dac which employs Dirac seems like a worthwhile investment in system optimization. And Dirac DLBC would be best of all, as it would allow you to create a 2+2 stereo system with full correction of each bass channel. But that's only available on AV Receivers or PC versions of Dirac. If you can use a PC as your source for everything, the recommendation would be to do that and use DLBC with a four channel DAC, which would definitely be superior to Dirac Live, or most anything else.

BTW, the vertical mic position (mic pointing at the ceiling) is for home theater, not 2 channel stereo sound. For stereo, the mic should be parallel with the floor.

 

[Audionaut]

I think most people don't understand how to read these responses.

Possibly a linguistic problem.
I have calculated the main resonances of the room, which result from the length, width and height.
The room is almost square, so the resonance at 37.5 Hz should be particularly noticeable.
The resonance resulting from the ceiling height is 80.5 Hz.

I don't think it will be possible to achieve a completely satisfactory result with equalizing alone.
Bass traps would be a good first acoustic measure.

 

[alankila]

Possibly a linguistic problem.
I have calculated the main resonances of the room, which result from the length, width and height.
The room is almost square, so the resonance at 37.5 Hz should be particularly noticeable.
The resonance resulting from the ceiling height is 80.5 Hz.

I don't think it will be possible to achieve a completely satisfactory result with equalizing alone.
Bass traps would be a good first acoustic measure.

Oh yes. I made a mistake there. I just think that people tend to usually look at the dip in the bass as the problem, when often it isn't a null, it's just a frequency that is not significantly aided by a resonance. So it's the peaking around the "dip" that are the real problems. Once you can switch mentally away from "dip = null", a different interpretation is possible. Nulls can of course be checked with tools such as group delay or using the spectrogram in some higher resolution mode than the default FFT mode. Wavelets and burst decay are quite illuminating, and these days I mostly use the burst decay.

As to absorption, there is little that even solid amount of bass trapping can achieve < 100 Hz, I guess, but it isn't nothing. Everything is easier after RT60 is brought down, and OP should definitely post some RT60 data so we could see what the decay times are and maybe compare these to room volumes too, to know if it's too little or too much... With that quantity of porous material, I bet the room is already quite dead.

 

[DVinylfan]

I think you've already done very well, Jeff. Getting in-room sound right is complicated.

Move the seat forward say about 60 cm, past the wall on the left

I think you are getting some very good advice here.

Agree with everything except the othering and discriminatory nonsense about 'needing therapy' for putting a towel over a TV when the basis of your thread is that you know little and you're here to learn.

 

[Multicore]

Agree with everything except the othering and discriminatory nonsense about 'needing therapy' for putting a towel over a TV when the basis of your thread is that you know little and you're here to learn.

i suspect thomas was joking about that.

our scientific experiments can sometimes look a bit weird. i remember a thread in which someone was very carefully testing a hypothesis about woofer "burn in" with experiments that involved, among other things, looking for differences in performance of drivers where the independent variable was temperature. i commended what i saw as the "nerd commitment to the cause", which i seriously admire. i really do. the experimenter replied remarking, iirc, that he had a moment of pause, while taking a woofer out of the fridge, wondering about what this act says about his own sanity.

 

[alex-z]

By far the best thing you can do for your system is add some form of DSP. It would be relatively easy to EQ your bass response into a more neutral state. High-passing the speakers will also reduce multi-tone distortion.

A Wiim Ultra could replace your streamer, DAC, and pre-amp with no loss of quality.

WiiM Ultra Streamer Preamp Review

This is a review and detailed measurements of the WiiM Ultra network streamer, DAC, phono stage and preamplifier. It was sent to me by the company and costs US $329. Physical attribute are modern and attractive enough. Alas, I can't say the same thing about the graphical interface. Icons seem...

www.audiosciencereview.com

The high frequency looks like a mic calibration issue. Measure each speaker at 1 metre distance and the mic pointed directly at the tweeter.

 

[Raymond_61]

THANK YOU EVERYONE!!!
A bit of information overload but that's OK! I'm convinced I've come to the right place. I will take every comment, question and recommendation seriously and do my best to apply them toward finding the solution.
I have lots of homework and I decided that before I start firing off rew files or measurements for you, I'll follow Keith's advice and become confident that my measurements are acceptable quality. That will take a while. But I will also look into other non-REW related things.
Sincere thanks again to all !

Jeff

 

[Raymond_61]

Well, out of curiosity I tried a few things this morning like swapping out interconnect cables and preamplifier and then removed the large bass traps on the front wall.
Interestingly, I noticed that I kept getting nearly the exact same measurement graph. I stuffed the mic into the space between the recliner cushion and the console (where the tv remote hides) and took a measurement. Same graph. So I asked ChatOn AI why something like this is happening. Getting the same measurement output regardless of changing other parameters. I received a list of things to check like input levels being too high. I made corrections in the REW preference settings and adjusted the mic input level and I'm not saying they are spot on perfect, but I'm closer to producing a valuable measurement. Thanks again to all for the push to be sure things are correct in REW ! Still so much more to learn.

 

[alankila]

Hello, some comments.

Figure out what's doing the distortion on right channel around 200 Hz. Is something rattling?

The horizontal lines are echoes in your left channel. The earliest is mere 2 ms after the main impulse. Right channel is much better, though it also has that 2 ms issue. Sound doesn't travel much in 2 ms, about 70 cm. Could this be a back wall reflection or something like that?

If this was equalized according to how I would do it, I'd do this:

I designed an about 1 dB/oct rise that starts around 2000 Hz and brought some peaks down using pretty gentle filters. This is only 8 filters, so would fit in e.g. Wiim streamer's DSP. It does a lot for the 30 and 80 Hz problem areas. I don't extend corrections much past 400 Hz, because they won't work anyways. Group delay plot is telling us -- if it isn't obvious, already -- that the 50 Hz is a cancellation. Huge dip there, and group delay is spiking, so system here is not in minimum phase and can't be corrected with a minimum phase equalizer. The excess group delay is an indication of how far away the system is from minimum phase.

Anyways, fix some of those early reflections and do the eq REW can compute you, and you'll have a pretty sweet-sounding system.

 

[Keith_W]

The horizontal lines are echoes in your left channel. The earliest is mere 2 ms after the main impulse. Right channel is much better, though it also has that 2 ms issue. Sound doesn't travel much in 2 ms, about 70 ms. Could this be a back wall reflection or something like that?

No, it's because he stuffed his mic into his recliner.

To the OP: please don't do this. Get yourself a measurement tripod with a boom. They are really inexpensive. Have you read this thread?

 

[alankila]

No, it's because he stuffed his mic into his recliner.

To the OP: please don't do this. Get yourself a measurement tripod with a boom. They are really inexpensive. Have you read this thread?

Oh. To the OP: it is perfectly acceptable to just hold microphone in hand, rather than involve some kind of object that contributes sound reflections to the microphone. Your body does some damage to the measurement, and it isn't entirely reproducible, but get the mic far away from your body and just hold it still while the sweep goes and you might do better. Amazon basic stands cost like 20 bucks IIRC. I'd order one immediately. Being able to just hang the mic in nearly free space is pretty useful so you don't end up chasing ghosts.

 

[Raymond_61]

Thanks again to all for the feedback, comments, analysis and suggestions!
I apologize to those who invested time trying to help in the midst of me having supplied measurements that were flawed due to my REW settings being messed up.
I have the answer(s) to my original question which brought me here. So for now I'm good and it's time to simply enjoy the music!
Over and out.
Jeff