Before and after Room Treatment

[Daverich4]

Here is an easy to use SBIR calculator which lets you understand the rough effects of each reflection. You can also play with REW room simulator.

SBIR calculator

SBIR calculator

tripp.com.au

Thanks for the link

 

[Daverich4]

Here is another quite handy way of locating reflections and where to place treatments: https://amcoustics.com/tools/amray
Visual path length & time calculator of the concept that Keith_W explained.

Quick side view example of a room. Draw the hard surfaces, select the right side "Raytracing algorithm", place speaker and listener. You can compare those to impulse responses, but do note that the 2d path lengths are different compared to actual 3d distance in a room, so this is not accurate, only approximation.
View attachment 542693

Thanks for the link.

 

[Daverich4]

What's wrong with using a mirror? Very simple to find reflection points.

This discussion was about how to find a specific specular reflection. I've already used the mirror method to locate the panels on the sides of the room.

 

[Bjorn]

This discussion was about how to find a specific specular reflection. I've already used the mirror method to locate the panels on the sides of the room.

I see. Unless you know the direction it's coming from, you can start by blocking the mic with a pillow at different angles. For example; block the area with a pillow of the mic above and front it. If this attenuates the specific reflection, you know it's coming from the front and above. And continue like this till you find where's it's coming from.

The first reflections are on thing as seen below, but clearly reflections can come from numerous places when the sound bounces off several surfaces before arriving at the listening position. Furnitures and possible angled walls/ceiling contributes as well. I've worked in some odd rooms where it took quite a bit of time to find the reflection point. But the use of a pillow (or small absorbent) helps to narrow it down much more quickly.

Apologies if this has already been answered.

 

[Bjorn]

The 2.6 ms reflection may very well come from the ceiling. I see you don't have any treatment there.

 

[Daverich4]

The 2.6 ms reflection may very well come from the ceiling. I see you don't have any treatment there.

You are quite possibly correct as the ceiling is worse than no treatment….

 

[klettermann]

That’s where I went wrong. I read the formula as (343*2.6)/1000. Math is not my strong suit. I have two strong candidates for reflections at that distance. Thanks.

I recently went through a very similar project to your own. I had great success plugging the raw scans into ChatGBT. It can analyze them and do all the math in seconds. I was sceptical at first and double checked, but it was all correct. Now I can't live without it. Just cut-and-paste the scans. Cheers,

 

[Daverich4]

I recently went through a very similar project to your own. I had great success plugging the raw scans into ChatGBT. It can analyze them and do all the math in seconds. I was sceptical at first and double checked, but it was all correct. Now I can't live without it. Just cut-and-paste the scans. Cheers,

I'm not sure what you mean by raw scans. The .mdat files?

 

[klettermann]

Example: paste an REW FR plot, impulse plot and room diagram. Ask for ETC analysis. That kind of thing works great.

 

[Daverich4]

Example: paste an REW FR plot, impulse plot and room diagram. Ask for ETC analysis. That kind of thing works great.

Thanks for the suggestion. While I consider myself a competent computer user so far I’ve not had any interest in AI. I’ll keep your suggestion in mind going forward however.

 

[LesterHiggins]

Thanks for the suggestion. While I consider myself a competent computer user so far I’ve not had any interest in AI. I’ll keep your suggestion in mind going forward however.

Man, I really empathize with you through this thread. I think everyone interested in optimizing their audio through empirical testing has gone through, and still goes through, the confusion and frustration you've described here, along with the exhaustion and the throwing in of the proverbial towel. It's great to set limits and not obsess too hard, when things start getting frustrating it's perfectly valid to just say "nope, not going to deal with this right now," it's not being pouty, it's being an adult who's capable of prioritizing effectively. I just tried Focus Fidelity, and I'm asking for a refund. All it does, just like Dirac, is make things not as loud. When you've done all this work, speaker placement, room treatment, subwoofer optimization, etc. etc. etc., FIR filters don't have much to actually do. They can't fix the unfixable, and that's all that's really left. I will say, the best results I got from physical room treatment were when I did the ceiling, not the walls, and it looks like you don't have any diffusion, that was a great addition as well. There are a bunch of people in the audio world that are super obsessive and go to extreme lengths to achieve some vision, some of them are really smart and kind and capable and helpful, and I listen to what they say here and apply it within reason. Some of them are basically superstitious weirdos with too much time and money on their hands, they tend not to last long here. I try to ask myself, "does this make me enjoy music more?" and then use the answer to determine if it's worth continuing with an attempt to improve what I hear or if I should just go ahead and kick back and hit play. TL;DR: you probably don't have much left you can actually do, try treating the ceiling and adding diffusion, then just put on some tracks and enjoy.

 

[LesterHiggins]

I recently went through a very similar project to your own. I had great success plugging the raw scans into ChatGBT. It can analyze them and do all the math in seconds. I was sceptical at first and double checked, but it was all correct. Now I can't live without it. Just cut-and-paste the scans. Cheers,

I've also found chatGPT, Claude, and Gemini oddly capable when it comes to audio engineering. For most other things? Hot garbage. But for audio, really good.

 

[Keith_W]

I just tried Focus Fidelity, and I'm asking for a refund. All it does, just like Dirac, is make things not as loud.

All DSP sacrifices volume for linearity. If you are losing a lot of volume after DSP, you need to overlay your pre-correction curve on top of your post-correction curve. Make sure both are acoustic measurements (and not simulations!!), taken at the same SPL, and from the same microphone position. You will easily see where the volume cuts have been made. Remedial solutions include: less aggressive DSP, and better volume matching between drivers. For example, if your speakers are way too loud compared to your subs, DSP will cut your speakers down by a lot. Or, if you have tried to correct a dip in the FR by setting your target too low, you will lose a lot of SPL.

I don't know enough about Focus Fidelity to know exactly how it works. But this is what I suggest you try first.

When you've done all this work, speaker placement, room treatment, subwoofer optimization, etc. etc. etc., FIR filters don't have much to actually do. They can't fix the unfixable, and that's all that's really left.

With ALL DSP, you need to try to give DSP as little work to do as possible. Subwoofers and speakers should be positioned so that you have as few dips in the frequency response (but peaks are OK). And you should temper your expectations about perfection. Good luck!

 

[LesterHiggins]

All DSP sacrifices volume for linearity. If you are losing a lot of volume after DSP, you need to overlay your pre-correction curve on top of your post-correction curve. Make sure both are acoustic measurements (and not simulations!!), taken at the same SPL, and from the same microphone position. You will easily see where the volume cuts have been made. Remedial solutions include: less aggressive DSP, and better volume matching between drivers. For example, if your speakers are way too loud compared to your subs, DSP will cut your speakers down by a lot. Or, if you have tried to correct a dip in the FR by setting your target too low, you will lose a lot of SPL.

I don't know enough about Focus Fidelity to know exactly how it works. But this is what I suggest you try first.



With ALL DSP, you need to try to give DSP as little work to do as possible. Subwoofers and speakers should be positioned so that you have as few dips in the frequency response (but peaks are OK). And you should temper your expectations about perfection. Good luck!

My point is that for me, with that preliminary work to give DSP as little work to do as possible (which includes physical room treatment), DSP does so little that it makes it entirely not worth the effort or expense, even with REW.

 

[Daverich4]

Man, I really empathize with you through this thread. I think everyone interested in optimizing their audio through empirical testing has gone through, and still goes through, the confusion and frustration you've described here, along with the exhaustion and the throwing in of the proverbial towel. It's great to set limits and not obsess too hard, when things start getting frustrating it's perfectly valid to just say "nope, not going to deal with this right now," it's not being pouty, it's being an adult who's capable of prioritizing effectively. I just tried Focus Fidelity, and I'm asking for a refund. All it does, just like Dirac, is make things not as loud. When you've done all this work, speaker placement, room treatment, subwoofer optimization, etc. etc. etc., FIR filters don't have much to actually do. They can't fix the unfixable, and that's all that's really left. I will say, the best results I got from physical room treatment were when I did the ceiling, not the walls, and it looks like you don't have any diffusion, that was a great addition as well. There are a bunch of people in the audio world that are super obsessive and go to extreme lengths to achieve some vision, some of them are really smart and kind and capable and helpful, and I listen to what they say here and apply it within reason. Some of them are basically superstitious weirdos with too much time and money on their hands, they tend not to last long here. I try to ask myself, "does this make me enjoy music more?" and then use the answer to determine if it's worth continuing with an attempt to improve what I hear or if I should just go ahead and kick back and hit play. TL;DR: you probably don't have much left you can actually do, try treating the ceiling and adding diffusion, then just put on some tracks and enjoy.

I’m not in a position to do any ceiling treatment. I am about to add a pair of subwoofers in an attempt to eliminate the 2 large dips in the right channel that I’ve not been able to fix with speaker placement and location of the MLP.

 

[LesterHiggins]

I’m not in a position to do any ceiling treatment. I am about to add a pair of subwoofers in an attempt to eliminate the 2 large dips in the right channel that I’ve not been able to fix with speaker placement and location of the MLP.

I needed a ladder in order to adjust my position when I hung the ceiling treatment here. /joking You could build something like an E-Z up canopy but the canopy ceiling is acoustic treatment instead of just shading. Subwoofers are annoying AF, especially multiple, especially if you don't have dual subwoofer outputs from your source. You have to connect them, get them both the full L/R signal so they can sum it to mono or if you just have L/R preamp out you have to find a way to sum that to mono or split it, or you daisy chain them if they have in and out, then you have to choose where to place them, then that introduces delay so you need DSP to set delay times, then it introduces the crossover challenge, how do you high pass your mains and low pass your subs, if that's your plan. Do you even hear anything you don't like, or are you just looking at measurements? Whatever you do, don't get SVS subwoofers because they have latency of 6ms from their onboard DSP that can't be disabled. I mean, dude your speakers are like twenty THOUSAND dollars. If you're unhappy with your bass, I think the issue has to be fundamentally internal to the primary system involved, by that I mean your mind. You want to improve your perception of your bass? Try meditating maybe?

 

[LesterHiggins]

I’m not in a position to do any ceiling treatment. I am about to add a pair of subwoofers in an attempt to eliminate the 2 large dips in the right channel that I’ve not been able to fix with speaker placement and location of the MLP.

Also, reading the manual for the speakers, you have them toed in too much and the MLP is too far away from them, at least in that photo. It says you're barely supposed to be able to see the surface of the inner side, but that's completely out of view in the pic. It also says the MLP should be around 1.5x the distance between the speakers away from them, but it looks more like 2 or 2.5 in the pic. They're rear ported and you might find that moving the absorption panels that are behind them to a side location or behind you helps.

 

[HiMu]

I am about to add a pair of subwoofers in an attempt to eliminate the 2 large dips in the right channel that I’ve not been able to fix with speaker placement and location of the MLP.

What is the room height and how high your ears/microphone is? Before committing to adding subwoofers try to identify if that dip/dips is caused by a vertical room mode. Just throwing in a couple of subwoofers on the floor might leave you even more frustrated if that doesn't solve the problem.

In my room I had to put subs on both left & right side walls, on stands about 1/3 of the room height to eliminate the floor-ceiling mode and the side wall modes. When I had them on the floor it sounded great when standing, until you sat down and the bass just vanished.

Could you take a measurements either significantly closer to ceiling or floor to rule out /troubleshoot if the dips are caused by the height mode? People who are interested in room acoustics can be (weirdly) passionate about helping others, like you, to get the best possible sound out of a sound system.

 

[Pauli]

Before:

After:

Apps used: REW, Hang Loose Convolver VST3 plugin, MEqualizer VST3 plugin, Audirvana Studio (Player).

MiniDSP UMIK-1 microphone.

 

[Daverich4]

Do you even hear anything you don't like, or are you just looking at measurements? Whatever you do, don't get SVS subwoofers because they have latency of 6ms from their onboard DSP that can't be disabled. I mean, dude your speakers are like twenty THOUSAND dollars. If you're unhappy with your bass, I think the issue has to be fundamentally internal to the primary system involved, by that I mean your mind. You want to improve your perception of your bass? Try meditating maybe?

Not sure what the price of my speakers has to do with Room Modes. To answer your first question, thanks to the help of a number of people on this site, especially Keith_W, my system sounds the best it ever has. So yes, my interest in adding subwoofers is partially measurements and partially because a number of additional benefits that are claimed for two or more beyond correcting room modes. I have no reason not to try them and if it doesn't work out I'll get rid of them.