Article: A New Listening Room Part Two: Acoustics, Speakers, DSP

[mitchco]

@yyz Agree with @firedog the UMIK-1 USB is great value being able to plug and play and not have to purchase a separate mic preamp and/or ADC. The accuracy of the mic is just fine for taking acoustic measurements.

 

One potential issue is clock rate offset and/or clock drift between the input (i.e. the USB mic with it's own clock) and the output (i.e. DAC). However, John Mulcahy has this fixed in the latest versions of REW. Bernt also has clock drift compensation in Audiolense 6.x and Uli has a special version of Acourate LogSweepRecorder that can be downloaded here for taking measurements with UMIK-1. In the case of Acourate, which uses ASIO, one will need to download Asio4All as well.

[ShawnC]

@The Computer Audiophile, How did you wire from your DAC or preamp to your left Amplifier?  Seeing all your equipment is on the right side (except the left amp and speaker). did you go under the floor/carpeting or above the ceiling? I'm assuming your using XLR for the runs.  I see a hole in the wall where it feeds from, just curious.

 

Maybe you could post a short video of your current setup, walking us through your Audio chain and seeing the back of your equipment, speakers and room layout.

 

Thanks, 

Shawn

[The Computer Audiophile]

14 minutes ago, ShawnC said:

@The Computer Audiophile, How did you wire from your DAC or preamp to your left Amplifier?  Seeing all your equipment is on the right side (except the left amp and speaker). did you go under the floor/carpeting or above the ceiling? I'm assuming your using XLR for the runs.  I see a hole in the wall where it feeds from, just curious.

 

I'm running balanced cables throughout my system. On the other side of the walls on each side of the listening room is a crawl space. I used a hole saw to drill holes on each side, through the floor. Then I ran the cable for the left channel under the floor & through the wall. Much better than going under the carpet.

 

Sure there are possible issues with length of cable and using a different circuit (although same audio sub-panel) for power, but there's no perfect system.

 

 

 

14 minutes ago, ShawnC said:

Maybe you could post a short video of your current setup, walking us through your Audio chain and seeing the back of your equipment, speakers and room layout.

 

Ah, that would be fun. I didn't think anyone would be interested.

[rickca]

3 minutes ago, The Computer Audiophile said:

Ah, that would be fun. I didn't think anyone would be interested.

So that's where the bodies are buried.

[yyz]

3 hours ago, mitchco said:

@yyz Agree with @firedog the UMIK-1 USB is great value being able to plug and play and not have to purchase a separate mic preamp and/or ADC. The accuracy of the mic is just fine for taking acoustic measurements.

 

One potential issue is clock rate offset and/or clock drift between the input (i.e. the USB mic with it's own clock) and the output (i.e. DAC). However, John Mulcahy has this fixed in the latest versions of REW. Bernt also has clock drift compensation in Audiolense 6.x and Uli has a special version of Acourate LogSweepRecorder that can be downloaded here for taking measurements with UMIK-1. In the case of Acourate, which uses ASIO, one will need to download Asio4All as well.

 

First of all let me thank you for your book, I like it. Thanks also for this detail set of instructions on the UMIK-1 USB. I think this alleviates my confusion about the synergy with the Acourate software and USB mics. I will finish reading your book to figure out what I need to do. Your statement that I may not need an ADC would be a massive saving for me. Whatever, the case I will learn something from your book and give your firm a call, most likely to fix my mistakes. Best way to learn is to make mistakes.

[ShawnC]

1 hour ago, The Computer Audiophile said:

Ah, that would be fun. I didn't think anyone would be interested.

Maybe so, I'm kind of a YouTube junkie, so that stuff interests me.

 

I also appreciate it when reviewers show pictures of their setup with the product their reviewing, verses stock photos from the manufacturer.  

[Middy]

Just lovely Chris and I won't even say you are lucky, just the hard work payed off. We benefit everyday so nice to see it flow the other way...

 

My evil side wishes you said:

No i tuned the Wilsons by asking the wife when she wondered in looking for socks and kicked them until they sounded sweet dude....

 

Or For $60,000 i am disappointed as they wont let me order off Amazon....

 

Happy 'Chris'   Mass mate to you and yours..

Thanks for a another great year on AS

Kind regards

Dave

Ps

My wife thinks DSP  is Desperately Seeking Praise

[Sal1950]

Chris & Mitch,

What incredible results from the room and DRC tuning,  WOW!

[buffalobill]

Comical. Spend a lot of money on a speaker with conventional ordinary direct radiating mid-range cone which will spray frequencies all around walls, floor, ceiling and then install acoustics to absorb the resulting distorted frequencies. The distorted frequencies are still there and dynamics are now reduced.   

[firedog]

6 hours ago, buffalobill said:

Comical. Spend a lot of money on a speaker with conventional ordinary direct radiating mid-range cone which will spray frequencies all around walls, floor, ceiling and then install acoustics to absorb the resulting distorted frequencies. The distorted frequencies are still there and dynamics are now reduced.   

 

What's comincal is your smug response. Or should I say sad.

 

Did you see the measurements? Did you read Chris' description? Have you ever done something similar in a room? Or are you just talking based on all sorts of doubtful "audiophile" assumptions without any actual knowledge of how using room treatments and measurements in this way can improve sound? 

[johniboy24]

@The Computer Audiophile

I have a question regarding the in-room response graph you posted. Are the before and after graphs even comparable? The "before" graph is at around 85db while the "after" graph is below 70db, so a lot quieter. I always thought if you put more energy into the room, so listen to music louder you will also experience more effect of the room (and more problems)?

[The Computer Audiophile]

36 minutes ago, johniboy24 said:

@The Computer Audiophile

I have a question regarding the in-room response graph you posted. Are the before and after graphs even comparable? The "before" graph is at around 85db while the "after" graph is below 70db, so a lot quieter. I always thought if you put more energy into the room, so listen to music louder you will also experience more effect of the room (and more problems)?

Let's ask @mitchco for an official response. 

[mitchco]

1 hour ago, johniboy24 said:

@The Computer Audiophile

I have a question regarding the in-room response graph you posted. Are the before and after graphs even comparable? The "before" graph is at around 85db while the "after" graph is below 70db, so a lot quieter. I always thought if you put more energy into the room, so listen to music louder you will also experience more effect of the room (and more problems)?

 

Hello @johniboy24 The before and after graphs are indeed at the same SPL. I have manually offset the "after" graph by reducing it's gain in REW so it is easier to compare when viewed in REW's overlays chart.

 

We calibrate sound systems at "reference" level, which is approximately 83 dB SPL at the LP. This is because our non-linear ears, relatively speaking, have the flattest frequency response in this SPL range and usually this is the monitoring level set for adjusting the final tonal balance for mixes and masters from the studio. A good reference is Bob Katz, mastering engineer's topic on Level Practices. So for "critical listening" one wants to adjust the SPL to around 77 dB SPL (for highly compressed material) to 83 dB SPL (for wide dynamic range) on a sound pressure level meter at the LP if you want the most accurate playback as far as tonal balance is concerned.

 

If using JRiver, I calibrate the loudness control in this range so when I have music on at "background" level, the loudness control is engaged to boost the bottom end to make up for the ears non-linear frequency response which becomes less sensitive to bass at lower levels than reference. The loudness control restores this balance to make the music sound full at lower listening levels.

 

Hope that helps.

[wgb113]

Chris,

 

The new space looks great, glad to hear that it's sounding great as well.  Addressing the room was a real ear-opener for me.  I'm going to attempt to add the icing (DSP) to the cake while I have some time off over the next couple of weeks using REW, UMIK-1 and Roon.

 

Bill

 

P.S. Jealous of those Ikea chairs...by the time I went to scoop up a pair they were gone!

[johniboy24]

@mitchco

thanks, perfect! 🙂

 

[The Computer Audiophile]

15 minutes ago, wgb113 said:

Chris,

 

The new space looks great, glad to hear that it's sounding great as well.  Addressing the room was a real ear-opener for me.  I'm going to attempt to add the icing (DSP) to the cake while I have some time off over the next couple of weeks using REW, UMIK-1 and Roon.

 

Bill

 

P.S. Jealous of those Ikea chairs...by the time I went to scoop up a pair they were gone!

Thanks Bill. Be sure to let us know how it goes with the DSP. The best part is that nothing is permanent. If you screw up the sound, just disable it :~)

 

Yes, the 1957 Ikea limited edition 2019 reproduction was quite a find! 

[thyname]

Thanks for sharing Chris! A lot of work I am sure, but it sounds like very rewarding.

 

I found the below paragraph from you frustrating. So we still have to go back to “trusting our ears”, even when it comes to applying DSP in a scientific way?

 

——-

 

At first I wasn't thrilled with the results. I believed the transients were rounded at the edges far too much for my taste. This coupled with the fact that I was used to listening without any DSP for my entire life, made me frustrated. I reported back to Mitch everything I heard, liked, and disliked. His response to me was very reassuring. He said not to worry because there are many industry standard curves to try and many small adjustments he can make to the filter. 

 

Over several weeks Mitch sent me more filters to try. I was traveling much of this time, so I assume we could've hammered out my issues pretty quick if I could dedicate more time to the effort. Mitch sent filters based on ITU, B&K and Bob Katz target curves before sending the EBU 3276 target curve. I liked the direction he was taking my system with the ITU curve, but when I pressed play with the EBU 3276 curve enabled, I was sold. My system was really singing. My room was out of the picture, and the music was right there in front of me. 

 

 

——

[The Computer Audiophile]

23 minutes ago, thyname said:

Thanks for sharing Chris! A lot of work I am sure, but it sounds like very rewarding.

 

I found the below paragraph from you frustrating. So we still have to go back to “trusting our ears”, even when it comes to applying DSP in a scientific way?

 

——-

 

At first I wasn't thrilled with the results. I believed the transients were rounded at the edges far too much for my taste. This coupled with the fact that I was used to listening without any DSP for my entire life, made me frustrated. I reported back to Mitch everything I heard, liked, and disliked. His response to me was very reassuring. He said not to worry because there are many industry standard curves to try and many small adjustments he can make to the filter. 

 

Over several weeks Mitch sent me more filters to try. I was traveling much of this time, so I assume we could've hammered out my issues pretty quick if I could dedicate more time to the effort. Mitch sent filters based on ITU, B&K and Bob Katz target curves before sending the EBU 3276 target curve. I liked the direction he was taking my system with the ITU curve, but when I pressed play with the EBU 3276 curve enabled, I was sold. My system was really singing. My room was out of the picture, and the music was right there in front of me. 

 

 

——

I wouldn’t be frustrated because of that experience. It’s actually quite cool because there are options to get the sound as close as possible to the source, at your listening position. That’s why there are several standards. It’s like if you prefer DSD over PCM. That’s not frustrating it’s just preference. 

[thyname]

18 minutes ago, The Computer Audiophile said:

I wouldn’t be frustrated because of that experience. It’s actually quite cool because there are options to get the sound as close as possible to the source, at your listening position. That’s why there are several standards. It’s like if you prefer DSD over PCM. That’s not frustrating it’s just preference. 

So again, trusting your ears? If a correctly applied DSP does not “fix” it the first time around, then wouldn’t you messing around with switching things around to match your listening preferences? I mean if the DSP is correctly applied at first go, as it should be, why would one tweak it? Or are you saying different people have different preferences in terms of how something sounds? Shocker!

[The Computer Audiophile]

23 minutes ago, thyname said:

So again, trusting your ears? If a correctly applied DSP does not “fix” it the first time around, then wouldn’t you messing around with switching things around to match your listening preferences? I mean if the DSP is correctly applied at first go, as it should be, why would one tweak it? Or are you saying different people have different preferences in terms of how something sounds? Shocker!

DSP isn’t black and white. There’s no way to capture the audio at the listening position and compare it to the source using a diff file and get real results. 
 

It seems your looking for something that can’t be found or you’re looking for me to explicitly state I have to trust my ears?

[thyname]

Just now, The Computer Audiophile said:

... or you’re looking for me to explicitly state I have to trust my ears?

Sure! 😂.

 

In all seriousness, the frustrating part with DSP is that one cannot be certain a certain setting will make thing better or worse. For your ears, that is. But you are right, it’s all worth experimenting until finding something that sounds better than current sound

[The Computer Audiophile]

25 minutes ago, thyname said:

Sure! 😂.

 

In all seriousness, the frustrating part with DSP is that one cannot be certain a certain setting will make thing better or worse. For your ears, that is. But you are right, it’s all worth experimenting until finding something that sounds better than current sound

It’s actually pretty easy to do. 

[STC]

39 minutes ago, The Computer Audiophile said:

There’s no way to capture the audio at the listening position and compare it to the source using a diff file and get real results. 

Actually you can but you need a binaural microphone, pink noise and correction filter. 

[The Computer Audiophile]

2 minutes ago, STC said:

Actually you can but you need a binaural microphone, pink noise and correction filter. 

But the main point was that you won’t get real results you can use. Capture all you want, it won’t be usable in terms of adjusting the DSP filter. 

[mitchco]

Hello. There are 4 common industry standard target frequency responses used to calibrate monitors in sound production control rooms. B&K, Toole and Olive, ITU and EBU 3276. And overlaid on one chart:

 

 

Given that each target has a +- 3 dB tolerance, effectively each target overlaps one another, all with a downward frequency response at the listening position. This is because loudspeakers are omnidirectional at low frequencies with narrowing directivity at higher frequencies. The rising bass energy yields a steady-state room curve with a downward tilt.

 

This is important to note because ones preference for one target or the other is based on a number of factors, all coming into play at once. Size of listening room, directivity index or polar response of the loudspeakers, distance from speakers to listener (there is a spec with a range), how much direct versus reflected sound is being heard at the listening position based on how lively or dead the listening environment is, also with spec and range of operation. All of these factors play into which target one prefers, with the common theme of how much or little high frequency response is required based on these factors.

 

For example, in my room with narrow directivity loudspeakers and a fairly large and lively room (600 ms broadband decay time) with a 9ft equilateral triangle, I prefer the Toole Olive target response. Sounds neutral to my ears given this combination of loudspeaker/room.

 

On the other hand, Chris's loudspeakers are wider directivity, also larger room. but with a 200ms broadband decay time. In order to hear the same perceived neutral response, more direct high frequency energy is required to arrive at Chris's listening position as compared to my loudspeakers in my room.

 

Normally, I would deliver all 4 target responses at once for your loudspeakers in your room. As Chris has shown in Roon, one can easily flip through different filters as music is playing and choose what sounds best to your ears. Toole and Olive have shown in participant listening studies that as Floyd Toole describes, accurate and preferred are synonymous. 

 

Due to schedules, I delivered Chris one filter set at a time, instead of all 4. And started with the target with the most rolled off top end 🙂 LOL! Exactly what he did not need. The 4th target delivered, weeks later, should have been the first. I would hazard a guess that is the frustration.