REW with miniDsp results help needed

C

ciotime

Audioholic
After getting 3 new SVS subs I had to redo my calibration. Spent a couple of days and hours doing REW with the miniDsp 2X4HD I was finally able to get the results which to me looks good. I was able to gets good results earlier but once I moved to take measurements to the Left and Right of the MLP it just was too different. Anyway I'm posting this in hopes of getting as much opinion as I can get and if there's some more I need to do to make it even better. Thanks.

SUB placement:
Sub 1-Left front wall 1/4th
Sub 2-Right side wall 1/4th
Sub 3-Rear middle wall
REW June.jpg
RT60 June.jpg
Spectrogram June.jpg
 
P

PENG

Audioholic Slumlord
The FR curve looks pretty good but I think there may room for improvement in the range 130-200 Hz (roughly) depending on which AVR you have as you may be able to use the mini with the Auto REQ such as Audyssey XT32/Editor App. I assume those curves in the first graph were plotted with the 3 subwoofers on only, can you post one with the subwoofers and LCR, or at least just sub+L+R to show the integrated effects?

Also, if those graphs were with smoothing applied, you can see opportunities better if you use 1/24 or remove smoothing altogether.

What is the second graph for?
 
C

ciotime

Audioholic
The FR curve looks pretty good but I think there may room for improvement in the range 130-200 Hz (roughly) depending on which AVR you have as you may be able to use the mini with the Auto REQ such as Audyssey XT32/Editor App. I assume those curves in the first graph were plotted with the 3 subwoofers on only, can you post one with the subwoofers and LCR, or at least just sub+L+R to show the integrated effects?

Also, if those graphs were with smoothing applied, you can see opportunities better if you use 1/24 or remove smoothing altogether.

What is the second graph for?
I'm using a Denon X3700H. The FR is a full range sweep ( mains on ) fr 10Hz to 20KHz with Audyssey turned on. The result is done with 1/12th smoothing. The graph posted is after doing EQ via the miniDsp as well as doing the Audyssey EQ using the app. I limited the Editor app to only 300Hz as well as limited it all the way to 20Hz for the subwoofer so that the app wouldn't affect the EQ done via the miniDsp.
The other 2 graphs are the RT60 and Spectrogram results.
 
MalVeauX

MalVeauX

Full Audioholic
Hi,

What is your crossover set to? I would focus on that. Measure your mains (without subs) sececondary to ensure you don't have any wild nulls that is not covered both ways (sub covering the null of the mains, mains covering nulls of the subs). Don't worry about what your subs are doing above your intended crossover and focus on where it actually will be doing work. Also, don't use smooth on bass. You want to see a sharp null if it exists so you can address it. In general, conventional wisdom is to make sure your subs are not forming equa-distant distances on a corner or wall, so be mindful of that with your 1/4th L/R wall (maybe you could explain what this means better?). As long as you're getting a good average at all listening positions, don't worry about the graph too much, just what each listening position will experience.

Very best,
 
C

ciotime

Audioholic
Hi,

What is your crossover set to? I would focus on that. Measure your mains (without subs) sececondary to ensure you don't have any wild nulls that is not covered both ways (sub covering the null of the mains, mains covering nulls of the subs). Don't worry about what your subs are doing above your intended crossover and focus on where it actually will be doing work. Also, don't use smooth on bass. You want to see a sharp null if it exists so you can address it. In general, conventional wisdom is to make sure your subs are not forming equa-distant distances on a corner or wall, so be mindful of that with your 1/4th L/R wall (maybe you could explain what this means better?). As long as you're getting a good average at all listening positions, don't worry about the graph too much, just what each listening position will experience.

Very best,
Thanks...crossover is currently set at 80Hz. My 3 sub setup is asymmetrical since I prefer to free up the space in front on one side coz the cabinets house my blu-ray collection. Normally it would be 2 subs in front and 1 sub at the middle back. I did do some reading and it turns out that Earl Geddes is a proponent of non-symmetrical setup. It also turns out that my setup is quite similar to layout 4 of miniDsp's multi-sub placement.

sub location.jpg
sub 1 and 2.jpeg
Cabinet.jpeg
Front1.jpg
 
C

ciotime

Audioholic
The last picture was my previous setup with only 1 sub...
 
MalVeauX

MalVeauX

Full Audioholic
Lovely room!

For your setups, try not to corner those subs so that they're literally equa-distant from the back wall and side wall; you want a rectangle where one distance is more than the other, not a square, otherwise you generate nasty reflections doing that. Asymmetry is actually good in a room like this in terms of bass as bass radiates as a sphere.

So to better look at what's going on and best setup that miniDSP, you'll want to measure your subs from lowest to 80hz (crossover) and leave it at that. Measure your mains without your subs too, so that you can see where the issues are. You can then compare these two so ensure you don't have a nasty null that isn't being covered by one or the other. Again remove all smoothing for this on your graphs.

Get the delay right on them. If your delay is set the same on all of them, then this will account for small issues. The delay is based on distance from speaker to your listening position(s) so that sound arrives at the same time, and not not with delays will will cause muddy results. So that's something to play with in your miniDSP is to add small delay to the speakers with the most distance so that they all match up in terms of their sound waves arriving at listening position at the same time. Your AVR will not be able to handle the delay on multi-subs. You'll do this yourself in mini DSP and you can use REW to measure your results.

Very best,
 
C

ciotime

Audioholic
I have no sub placed in a corner. Sub 1 is 1/4 front wall. Sub 2 1/4 is right side wall. Sub 3 is rear middle wall. So basically there are 3 subs in each wall except for the left side wall since I only have 3 subs.
"So that's something to play with in your miniDSP is to add small delay to the speakers with the most distance so that they all match up in terms of their sound waves arriving at listening position at the same time. "-I think you mean to ADD delay to the subs CLOSEST to the MLP right? Coz the closest subs sound waves will arrive earlier at the MLP. Anyway yes all 3 subs have different delays. Sub 1 being the farthest has no delay while sub 2 has a little delay and sub 3 has the biggest delay since it's located just about 3 feet from the MLP.
 
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MalVeauX

MalVeauX

Full Audioholic
Hi, yes, you would be adding delay to the closer subs, sorry for any confusion of wording. You should be able to measure this with REW to figure out your timings needed. And then measure with REW for SPL and response at listening position for final result. And compare to your mains without subs engaged, so to see what they do. Then measure them all together perhaps to see a summed result.

Very best,
 
P

PENG

Audioholic Slumlord
I'm using a Denon X3700H. The FR is a full range sweep ( mains on ) fr 10Hz to 20KHz with Audyssey turned on. The result is done with 1/12th smoothing. The graph posted is after doing EQ via the miniDsp as well as doing the Audyssey EQ using the app. I limited the Editor app to only 300Hz as well as limited it all the way to 20Hz for the subwoofer so that the app wouldn't affect the EQ done via the miniDsp.
The other 2 graphs are the RT60 and Spectrogram results.
Audyssey Sub EQ HT can only time aligned two subs so if you have 3 then your option is to Y connected two together and let Audyssey aligned the 2 in 1 group with the other sub, that's per Audyssey's recommendation iirc. In your setup, I believe you will likely be better off placing the one of the side to the front so that the 3 subs will be equidistant to your mlp.

I know its a lot of work but I would suggest you try using Audyssey without the minidsp, but use the App with Ratbuddyssey and see if you can get better results. If not, then you can go back to the mini and see if you can further improve the results such as relocating the side sub to the front and place them equidistantly. You mentioned Geddes, but when he said those things he might not have today's highly capable REQ in mind.

There is a chance that you may be surprised with the results you can get without the mini though. Below are some of my graphs that show what I manage to achieve (+/- 1 dB, 20-125 Hz at 1/12 smoothing) after a few hours of tweaking with the App and Rat. Without manual tweaking, Audyssey alone was only able to get me within about +/- 3.5 dB for the same range.

The minidsp is of course very useful for time aligning multiple subs, but I think the trade of is, you end up with more wires, output limit of 2 V and the filters are of the basic IIR/PEQ types whereas Audyssey's would have higher resolution and in my experience, it can do a better job when helped with manual tweaking using the App+Rat. That's just based on my experience, ymmv but you never know unless you try.

I wouldn't bother with the RT60 because unless your room is large enough the results are supposedly not meaningful below a few hundred Hz. REW suggested the use of RT60 delay, waterfalls and Spectrograms.

1623699658016.png


1623699802107.png


9 Positions average, with mic placed 10 inches between positions to the left, right, upper row and lower row positions:

1623700848674.png


1623701040194.png
 
Last edited:
P

PENG

Audioholic Slumlord
I limited the Editor app to only 300Hz as well as limited it all the way to 20Hz for the subwoofer so that the app wouldn't affect the EQ done via the miniDsp.
That could potentially allow your big towers to interact with your 3 subs negatively. I think it is better to let Audyssey EQ/integrated the bass capable towers with the subs, even if the subs are already EQ'ed by the minidsp. After running Audyssey, you can always try both limit (or not) the EQ range (by Audyssey) of the sub as you are doing now and see if you prefer one way over the other, and then plot graphs for both and see what it shows.
 
C

ciotime

Audioholic
That could potentially allow your big towers to interact with your 3 subs negatively. I think it is better to let Audyssey EQ/integrated the bass capable towers with the subs, even if the subs are already EQ'ed by the minidsp. After running Audyssey, you can always try both limit (or not) the EQ range (by Audyssey) of the sub as you are doing now and see if you prefer one way over the other, and then plot graphs for both and see what it shows.
Thanks for the advice. I didn't use a Y splitter since I'm using the miniDsp. I did try out using just the Audyssey app without the miniDsp and the sub regions FR was bad.

1) "In your setup, I believe you will likely be better off placing the one of the side to the front so that the 3 subs will be equidistant to your mlp."-I prefer to free up one side of the front's space coz the cabinets there store all my Blu ray disc and it would be too much of a hassle to move one sub every time I need to open the cabinets. I've attached a picture here to show one of the cabinets opened. All the wooden areas in the front are all functional cabinets ( columns & below the screen )

2) "That could potentially allow your big towers to interact with your 3 subs negatively. I think it is better to let Audyssey EQ/integrated the bass capable towers with the subs, even if the subs are already EQ'ed by the minidsp.
"-If I don't limit the Audyssey's Sub Freq Range won't it in effect alter/change ALL the EQ/Tweaking I did on the miniDsp? All the miniDsp help videos I've seen tell you to adjust the subs Freq Range on the MultEQ to the lowest limit thus preventing the app to change one's miniDsp settings.

3) Also do you agree to limit the MultEQ Freq Range on ALL the speakers to about the 300Hz-500Hz ( Schroeder Freq )? I also read this article "There is a belief that room correction should only be applied to frequencies below 300 Hz because that is the frequency range in which most of the room problems occur. This belief is based on an inherent assumption that a properly designed loudspeaker will perform as desired at higher frequencies and thus require no correction. "
 
P

PENG

Audioholic Slumlord
Thanks for the advice. I didn't use a Y splitter since I'm using the miniDsp. I did try out using just the Audyssey app without the miniDsp and the sub regions FR was bad.

1) "In your setup, I believe you will likely be better off placing the one of the side to the front so that the 3 subs will be equidistant to your mlp."-I prefer to free up one side of the front's space coz the cabinets there store all my Blu ray disc and it would be too much of a hassle to move one sub every time I need to open the cabinets. I've attached a picture here to show one of the cabinets opened. All the wooden areas in the front are all functional cabinets ( columns & below the screen )

2) "That could potentially allow your big towers to interact with your 3 subs negatively. I think it is better to let Audyssey EQ/integrated the bass capable towers with the subs, even if the subs are already EQ'ed by the minidsp.
"-If I don't limit the Audyssey's Sub Freq Range won't it in effect alter/change ALL the EQ/Tweaking I did on the miniDsp? All the miniDsp help videos I've seen tell you to adjust the subs Freq Range on the MultEQ to the lowest limit thus preventing the app to change one's miniDsp settings.

3) Also do you agree to limit the MultEQ Freq Range on ALL the speakers to about the 300Hz-500Hz ( Schroeder Freq )? I also read this article "There is a belief that room correction should only be applied to frequencies below 300 Hz because that is the frequency range in which most of the room problems occur. This belief is based on an inherent assumption that a properly designed loudspeaker will perform as desired at higher frequencies and thus require no correction. "
How about putting the sub on the side right next to the one in the front? If they are identical, the center speaker can straddle over them.

In my opinion, Audyssey would not mess with the minidsp's EQ that much because it would apply the filters as required only. So if the mini has done a good job, Audyssey should in theory, leave things alone, or do very little, and there is nothing that cannot be easily fixed using the App anyway. If Audyssey does mess things up, the REW graphs will show it, you could then either use the App to fix it, or limit the Audyssey EQ range to 20 Hz again. You have the choice and final say based on the results. I don't know why the help video you watched would preclude trying it both ways. I spent many hours playing with using minidsp only, Audyssey only, and both, and I got the best result by using both. However, I found using Audyssey only was good enough for me such that it is not worth having the extra wires laying around, so I stopped using the mini. Now that I can use the App, the results I managed to achieve in a few hours is much better than I thought would be possible. By the way, my room isn't that good at all, you can see it in the graph Audyssey on vs off:

1623777243709.png



You are getting good results as it is now but I do think from 100 Hz up there is room for improvements. I just thought you have too much of a drop going from 20 Hz to 240 Hz, a little boost to the mid bass wouldn't be bad.

If nothing else, I think even just lowering the subwoofer levels by 3 dB should help narrow the gap and improve the balance too. That being said, I am just commenting based on the FR graphs. At the end of the day, if you prefer the way your bass response sounds now, then you are good to go.
 

Attachments

C

ciotime

Audioholic
How about putting the sub on the side right next to the one in the front? If they are identical, the center speaker can straddle over them.

In my opinion, Audyssey would not mess with the minidsp's EQ that much because it would apply the filters as required only. So if the mini has done a good job, Audyssey should in theory, leave things alone, or do very little, and there is nothing that cannot be easily fixed using the App anyway. If Audyssey does mess things up, the REW graphs will show it, you could then either use the App to fix it, or limit the Audyssey EQ range to 20 Hz again. You have the choice and final say based on the results. I don't know why the help video you watched would preclude trying it both ways. I spent many hours playing with using minidsp only, Audyssey only, and both, and I got the best result by using both. However, I found using Audyssey only was good enough for me such that it is not worth having the extra wires laying around, so I stopped using the mini. Now that I can use the App, the results I managed to achieve in a few hours is much better than I thought would be possible. By the way, my room isn't that good at all, you can see it in the graph Audyssey on vs off:

View attachment 48558


You are getting good results as it is now but I do think from 100 Hz up there is room for improvements. I just thought you have too much of a drop going from 20 Hz to 240 Hz, a little boost to the mid bass wouldn't be bad.

If nothing else, I think even just lowering the subwoofer levels by 3 dB should help narrow the gap and improve the balance too. That being said, I am just commenting based on the FR graphs. At the end of the day, if you prefer the way your bass response sounds now, then you are good to go.
Thanks again Peng for the advice...as you suggested I'll give it a shot in a couple of days to have both the miniDsp+Audyssey and just Audyssey only and compare the results.

"How about putting the sub on the side right next to the one in the front? If they are identical, the center speaker can straddle over them. "-You mean 2 subs beside each other? Wouldn't that make them be co-located? Doesn't that defeat the purpose of getting 2 subs? Yes both are PB1000 PRO's.

"You are getting good results as it is now but I do think from 100 Hz up there is room for improvements."-100Hz up are all being done by the Audyssey MultEQ app. I only EQ'd using the miniDsp from 10Hz-100Hz.

" I just thought you have too much of a drop going from 20 Hz to 240 Hz, a little boost to the mid bass wouldn't be bad. "-Maybe its coz I applied a house curve from 100Hz to 25Hz. I purposely created a +8dB slope going fr 100Hz-25Hz.
 
P

PENG

Audioholic Slumlord
Wouldn't that make them be co-located? Doesn't that defeat the purpose of getting 2 subs? Yes both are PB1000 PRO's.
Yes, co-locate, since you cannot place the 2nd one on the left symmetrically because of the cabinet, your can place them side by side just to gain more output. The two being identical subs there shouldn't be much cancellation when placed side by side or stacked (stacked wouldn't look good in your case, I assume..). You will still have the 2nd sub on the opposite side to help even things up. That way, Sub EQ HT can actually do the job it is designed to do, that is to time align two subwoofers (Y-connect the two side by side one) and may end up not needing the miniDSP at all.

I can't say it placing them side by side would work better for sure, but it is so easy to find out. The PB1000Pros are not too heavy to move.:) If you want some expert opinion before trying, email Ed Mullen at SVS, or ask ShadyJ.

minidsp makes great products, but I do feel sometimes people tend to over kill using one for EQ when it isn't necessary when XT32 Sub EQ HT can do the job well enough. As mentioned, I have one (4XHD) too, and since I couldn't sell mine (hard to find a buyer in Canada), I may end up spending another $200 to get it FW updated for use it with Dirac Live in one of my two channel systems. Otherwise it would have been a total waste of money. As always, though ymmv..
 
C

ciotime

Audioholic
Ok I've re-measured and posted the graph's below.

First graph-No smoothing/Sub only and mains only/with miniDsp Audyssey ON/MultEQ Filter Freq Range LIMIT to 450Hz on all speakers/SUB limit to 20Hz

Second graph-No smoothing/Sub only and mains only/with miniDsp Audyssey ON/MultEQ Filter Freq Range LIMIT to 450Hz on all speakers/SUB limit to 250Hz/added house curve using Ratbuddyssey

Third graph-No smoothing/Full range comparison of First and Second graph/added +6dB to sub trim level/BLUE is first graph Brown is from the second graph with no limit to the sub in MultEQ Filter Freq Range



p1.jpg
p2.jpg
FR.jpg
 

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