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post #2521 of 3189 Old 12-13-2014, 07:14 PM
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The laptop is probably dropping the power. Are you getting any messages about having to resync the mini-dsp?
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post #2522 of 3189 Old 12-13-2014, 07:20 PM
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No, that isn't the issue. In fact, I have just figured out what is happening. I have my four ULS-15's Auto-On switch set to Auto, and the subs are going to sleep. Without the MiniDSP in the signal path, the subs never go to sleep. What is it about the signal coming from the MiniDSP that is below the threshold for keeping my subs awake?

The removal and re-insertion of the USB cable simply caused a pop to wake the subs up temporarily, and while I was sitting here listening to music (with heavy bass content at a reasonably loud level), the subs simply went back to sleep.

So, for the time being, I have configured the subs to be always on. Can anyone shed any light on why the subs are going to sleep?
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post #2523 of 3189 Old 12-13-2014, 09:55 PM
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Quote:
Originally Posted by AustinJerry View Post
No, that isn't the issue. In fact, I have just figured out what is happening. I have my four ULS-15's Auto-On switch set to Auto, and the subs are going to sleep. Without the MiniDSP in the signal path, the subs never go to sleep. What is it about the signal coming from the MiniDSP that is below the threshold for keeping my subs awake?

The removal and re-insertion of the USB cable simply caused a pop to wake the subs up temporarily, and while I was sitting here listening to music (with heavy bass content at a reasonably loud level), the subs simply went back to sleep.

So, for the time being, I have configured the subs to be always on. Can anyone shed any light on why the subs are going to sleep?
Can u use splitters right before each sub and run the splitters into the L and R inputs? This will increase the voltage the amp see's and should wake it easier.
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post #2524 of 3189 Old 12-14-2014, 05:46 AM
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It is certainly worth a try. I assume this will alter the sub's output levels, so a new Audyssey calibration will be required, correct? I'll try the Y-cable and measure to see if the output level changes. Thanks for the suggestion!
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post #2525 of 3189 Old 12-14-2014, 06:02 AM
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If you put a splitter in then won't it just reduce the sub trim by 6dB to compensate? ie net result is no change
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post #2526 of 3189 Old 12-14-2014, 06:14 AM
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What is the solution for miniDSP to balanced?

Example: RCA in... XLR out. Does Mini DSP handle this ok?

-

"Too much is almost enough. Anything in life worth doing is worth overdoing. Moderation is for cowards."
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post #2527 of 3189 Old 12-14-2014, 06:36 AM
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Originally Posted by 3ll3d00d View Post
If you put a splitter in then won't it just reduce the sub trim by 6dB to compensate? ie net result is no change
I am testing right now. I connected the Y-cable while outputting the level setting test tone to the sub. The Y-cable increased the sub's output by ~6dB.

While I was outputting the test signal, which was going to all four of my subs at a level of -3dB (according to the AVR menu), I noticed that none of the other three subs was waking up. So, I gradually increased the output level to the sub channel and the other subs woke up when the trim reached +5dB.

I am now waiting for the sub with the Y-cable to go back to sleep so I can test whether it wakes up at the -3dB setting, which would mean that the Y-cable is a solution to the problem.

I am still having some difficulty understanding why this is an issue with the MiniDSP in the signal path, when I have never had an issue without the MiniDSP. Of course, I could simply leave the subs on all the time, but I would prefer not to do that.
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post #2528 of 3189 Old 12-14-2014, 06:57 AM
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OK, here are the results.

With all four subs "asleep", I started the sub channel test tone at -3dB. None of the subs woke up. I gradually increased the trim level, and the sub with the Y-cable woke up at -1dB, while the other three subs didn't wake up until +5dB. So, the Y-cable improves the situation, but just falls short of a viable solution. By this I mean that I would need to run the sub channel 2-3dB hot in order to keep the subs awake. While running the subs hot may seem like an acceptable solution, and indeed many would naturally run their subs hot, I would prefer to find a solution that allows me to set the sub channel level to the "correct" level, i.e. producing 75dB at the MLP.

I am now re-visiting how I have the subs set up with the MiniDSP. Here is the process (using the 4-Way Advanced Plug-In):

- Gain-match all four subs.
- With room correction turned off, measure the output level of the combined four subs at the MLP (approximately 89dB).
- Using the input level control on the MiniDSP, adjust the level to read 75dB at the MLP (which is a setting of -14dB in the current configuration).
- With the combined level at 75dB, run the Audyssey calibration, which sets the sub channel trim to -3dB.
- Using the REW mic, verify that the AVR sub channel setting of -3dB indeed produces a level of 75dB at the MLP (it does).

Can anyone suggest a change in my setup technique that would result in higher voltage to the subs, yet maintain the 75dB sub level at the MLP?
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post #2529 of 3189 Old 12-14-2014, 07:32 AM
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It is not obvious why the voltage that produces 75dB would change in either case. Have you measured this with a multimeter with the minidsp in place and without?
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post #2530 of 3189 Old 12-14-2014, 08:09 AM
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Quote:
Originally Posted by 3ll3d00d View Post
It is not obvious why the voltage that produces 75dB would change in either case. Have you measured this with a multimeter with the minidsp in place and without?
Nope. I have a multimeter, so I should give that a try.
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post #2531 of 3189 Old 12-14-2014, 08:58 AM
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Quote:
Originally Posted by Mfusick View Post
What is the solution for miniDSP to balanced?

Example: RCA in... XLR out. Does Mini DSP handle this ok?
curious how to setup for different input and output sensitivity as well.
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post #2532 of 3189 Old 12-14-2014, 11:39 AM
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Quote:
Originally Posted by Mfusick View Post
What is the solution for miniDSP to balanced?

Example: RCA in... XLR out. Does Mini DSP handle this ok?
If i understand you correctly, yes.

Assuming your using a balanced mini.... IDK what the unbalanced version can do but the balanced handles it fine.
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post #2533 of 3189 Old 12-14-2014, 08:58 PM
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Quote:
Originally Posted by AustinJerry View Post
OK, here are the results.

With all four subs "asleep", I started the sub channel test tone at -3dB. None of the subs woke up. I gradually increased the trim level, and the sub with the Y-cable woke up at -1dB, while the other three subs didn't wake up until +5dB. So, the Y-cable improves the situation, but just falls short of a viable solution. By this I mean that I would need to run the sub channel 2-3dB hot in order to keep the subs awake. While running the subs hot may seem like an acceptable solution, and indeed many would naturally run their subs hot, I would prefer to find a solution that allows me to set the sub channel level to the "correct" level, i.e. producing 75dB at the MLP.

I am now re-visiting how I have the subs set up with the MiniDSP. Here is the process (using the 4-Way Advanced Plug-In):

- Gain-match all four subs.
- With room correction turned off, measure the output level of the combined four subs at the MLP (approximately 89dB).
- Using the input level control on the MiniDSP, adjust the level to read 75dB at the MLP (which is a setting of -14dB in the current configuration).
- With the combined level at 75dB, run the Audyssey calibration, which sets the sub channel trim to -3dB.
- Using the REW mic, verify that the AVR sub channel setting of -3dB indeed produces a level of 75dB at the MLP (it does).

Can anyone suggest a change in my setup technique that would result in higher voltage to the subs, yet maintain the 75dB sub level at the MLP?
Jerry,

neutro wrote a guide on how to tutorial using MiniDSP with multiple subs here: Tutorial: Dual sub integration using the MiniDSP

The only thing I was uncomfortable with the tutorial is have the gains on the sub set a maximum and using the level trims on the MiniDSP to adjust.

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post #2534 of 3189 Old 12-14-2014, 09:11 PM
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I read that guide but unfortunately did not find it that useful. What I have found in my experiments today is that the On/Off switching on the ULS-15 subs is very sensitive to the output level from the MiniDSP, which in my case is determined by the level control in the Input block. What I did was gain-match the subs (not level-match as per Neutro's suggestion). Then, I measured the four-sub combined level at the MLP and used the level control to adjust overall output to 75dB in preparation for the Audyssey calibration. The first time I did this, the input level control ended up at -18dB, which did not provide a strong enough signal to wake the subs up. While observing the power indicator on the subs, I gradually increased the output level and observed that the subs turned on when the level control reached -12dB.

So, I ran through the whole process a second time, this time gain-matching the subs at a lower level. When measuring the combined output, I was able to achieve 75dB with an input level of -8dB, which provided a strong enough signal to turn the subs on and keep them on. What puzzles me is that I have not seen any indication that anyone else has seen this issue. Regardless, it seems to be resolved now.
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post #2535 of 3189 Old 12-15-2014, 07:27 AM
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post #2536 of 3189 Old 12-15-2014, 08:28 AM
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Quote:
Originally Posted by raynist View Post
I ran an audyssey calibration today (using boom mic) and then did the sub distance tweak (purple line). I then used a minidsp to add in a house curve (red line) After doing that I notice in the graph that for the house curve run dropped a bit from 80-120. Do I need to do the sub distance tweak again?

No smoothing:


I really wasn't sure how to do the house curve in REW so i just did it in the minidsp plugin, is this the correct way? I am open to suggestions.

Ray,

Have you seen this article from Wayne over at HTS? Very informative and helped me a lot. The House Curve stuff is near the bottom.
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post #2537 of 3189 Old 12-15-2014, 05:17 PM
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Quote:
Originally Posted by AustinJerry View Post
I read that guide but unfortunately did not find it that useful. What I have found in my experiments today is that the On/Off switching on the ULS-15 subs is very sensitive to the output level from the MiniDSP, which in my case is determined by the level control in the Input block. What I did was gain-match the subs (not level-match as per Neutro's suggestion). Then, I measured the four-sub combined level at the MLP and used the level control to adjust overall output to 75dB in preparation for the Audyssey calibration. The first time I did this, the input level control ended up at -18dB, which did not provide a strong enough signal to wake the subs up. While observing the power indicator on the subs, I gradually increased the output level and observed that the subs turned on when the level control reached -12dB.

So, I ran through the whole process a second time, this time gain-matching the subs at a lower level. When measuring the combined output, I was able to achieve 75dB with an input level of -8dB, which provided a strong enough signal to turn the subs on and keep them on. What puzzles me is that I have not seen any indication that anyone else has seen this issue. Regardless, it seems to be resolved now.
Jerry,

I've taken the MiniDSP 2x4 out of the signal chain as it wasn't really helping me dealing with the room modes and smoothing the response.

Wondering if the sub plate amp sensitivity factor might have a factor in your setup. I recall that during tests with MiniDSP in the chain, had the sub powered ON all the time. Once the tests were done, has it switched in the AUTO mode. At low listening volumes and using Audyssey Dynamic Volume, it would kick the sub out of sleep mode. Just to be sure, used a y-splitter RCA and connected both left+right at the sub plate amp to get an extra +6dB signal boost.

One thing I did notice is that with the MiniDSP in the audio chain, there is some signal loss around 7dB to 9dB. I.e. Without the miniDSP the sub plate amp is at a lower gain level.

Will be getting a 2nd sub to help deal with the room mode issues. Would like to get an understanding of how you set up your multiple subs. Appreciate if you can advise.

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post #2538 of 3189 Old 12-15-2014, 06:07 PM
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Originally Posted by steveting99 View Post
Jerry,

I've taken the MiniDSP 2x4 out of the signal chain as it wasn't really helping me dealing with the room modes and smoothing the response.

Wondering if the sub plate amp sensitivity factor might have a factor in your setup. I recall that during tests with MiniDSP in the chain, had the sub powered ON all the time. Once the tests were done, has it switched in the AUTO mode. At low listening volumes and using Audyssey Dynamic Volume, it would kick the sub out of sleep mode. Just to be sure, used a y-splitter RCA and connected both left+right at the sub plate amp to get an extra +6dB signal boost.

One thing I did notice is that with the MiniDSP in the audio chain, there is some signal loss around 7dB to 9dB. I.e. Without the miniDSP the sub plate amp is at a lower gain level.

Will be getting a 2nd sub to help deal with the room mode issues. Would like to get an understanding of how you set up your multiple subs. Appreciate if you can advise.
I plan on writing up the procedure I used to dial in my four-sub configuration. I should have it completed in the next day or two while it is fresh in my mind. I'll make sure you are copied when the procedure is completed.
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post #2539 of 3189 Old 12-15-2014, 06:32 PM
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Originally Posted by AustinJerry View Post
I plan on writing up the procedure I used to dial in my four-sub configuration. I should have it completed in the next day or two while it is fresh in my mind. I'll make sure you are copied when the procedure is completed.

I am hoping that you will post this information here?

Al
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post #2540 of 3189 Old 12-15-2014, 06:57 PM
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Quote:
Originally Posted by AustinJerry View Post
- Gain-match all four subs.
- With room correction turned off, measure the output level of the combined four subs at the MLP (approximately 89dB).
- Using the input level control on the MiniDSP, adjust the level to read 75dB at the MLP (which is a setting of -14dB in the current configuration).
- With the combined level at 75dB, run the Audyssey calibration, which sets the sub channel trim to -3dB.
- Using the REW mic, verify that the AVR sub channel setting of -3dB indeed produces a level of 75dB at the MLP (it does).

Can anyone suggest a change in my setup technique that would result in higher voltage to the subs, yet maintain the 75dB sub level at the MLP?
Don't use the input level control on the mini-dsp to adjust levels.

I would set the sub trim on the AVR to +/- 0 dB, the AVR volume to +/- 0 dB, the input level on the mini-dsp at maximum, and then gain match each sub with their own level knob. If you gain match each sub to 72 dB, this should get you in the ball park, where the AVR after Audyssey should set the sub trim to around -3 dB.

If you want to get anal, you should check your sub pre-outs to ensure you are not clipping the input stage of the mini-dsp.

Last edited by Audionut11; 12-15-2014 at 07:00 PM.
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post #2541 of 3189 Old 12-15-2014, 07:16 PM
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Quote:
Originally Posted by Audionut11 View Post
Don't use the input level control on the mini-dsp to adjust levels.

I would set the sub trim on the AVR to +/- 0 dB, the AVR volume to +/- 0 dB, the input level on the mini-dsp at maximum, and then gain match each sub with their own level knob. If you gain match each sub to 72 dB, this should get you in the ball park, where the AVR after Audyssey should set the sub trim to around -3 dB.

If you want to get anal, you should check your sub pre-outs to ensure you are not clipping the input stage of the mini-dsp.
I set the sub trim to zero as well. When you play the sub level-setting test tone from the AVR, the MV is automatically set to zero. So I think we are saying the same thing--the combination of the sub gain matching and the input level on the MiniDSP result in a setting that is within the tolerances for the Audyssey calibration. I could have played around with the gain-matching settings until I found a value that was correct for an input setting of zero. Instead, I picked a gain-setting value, and adjusted the level on the MiniDSP to zero in on 75dB at the MLP. Two ways to skin the same cat. However, as I found out, if the input level is too low, the subs go to sleep.
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post #2542 of 3189 Old 12-15-2014, 07:21 PM
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Two ways to skin the same cat.
Yes. But do some research on gain matching, and then decide if using the input level on the mini-dsp is the most appropriate method of skinning that cat.

In essence, you are reducing the Signal to Noise Ratio of the mini-dsp when you lower the input level. You may not notice this in practice, but you are noticing other side effects (subs go to sleep).
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post #2543 of 3189 Old 12-15-2014, 08:32 PM
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Originally Posted by Audionut11 View Post
Yes. But do some research on gain matching, and then decide if using the input level on the mini-dsp is the most appropriate method of skinning that cat.

In essence, you are reducing the Signal to Noise Ratio of the mini-dsp when you lower the input level. You may not notice this in practice, but you are noticing other side effects (subs go to sleep).
I am not disagreeing at all, and I think your approach is perfectly sound. However, it can take a bit more time. If the objective is to achieve a combined sub output of 75dB at the MLP before runnig Audyssey, it might take several attempts to find the right gain on the subs to achieve this. I know it doesn't need to be exactly 75dB, but it should be reasonably close. And as long as the input level on the MiniDSP isn't too low, the subs don't go to sleep (which is what I found out).

So, unless there are other side effects I am aware of, I still think my approach works. If I need to re-do it, I might select a slightly lower sub gain so that the input level on the MiniDSP is closer to zero--nothing wrong with that at all.
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post #2544 of 3189 Old 12-15-2014, 09:19 PM
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Originally Posted by AustinJerry View Post
If the objective is to achieve a combined sub output of 75dB at the MLP before runnig Audyssey, it might take several attempts to find the right gain on the subs to achieve this. I know it doesn't need to be exactly 75dB, but it should be reasonably close.
The objective is to get it in the ballpark, so that the AVR doesn't need a large adjustment for the sub trim. Read: Gain Matching.

You have 3 level controls in your signal path Jerry. AVR, mini-dsp, sub. You seem to see the importance of proper level control for the AVR, neglecting the other 2 devices.

At a maximum, you gain 12 dB from 4 subs over 1. In this instance, a reduced sub trim on your AVR will reduce the chances of clipping the input stage of the mini-dsp (0.9v input).
If you shoot for 70-72 dB for each sub, you will be right on the money.

Currently, you have the AVR level (sub trim) probably a little to high, the mini-dsp way to low (8 dB by your last account), and the subs (at least 8 dB) to high. Normally I wouldn't care, since it's simply your listening experience. But you are respected around these woods, and plan on documenting your experiences. So in this case, I would rather see you take some more care in gain matching your devices.
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post #2545 of 3189 Old 12-16-2014, 04:30 AM
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Quote:
Originally Posted by Audionut11 View Post

Currently, you have the AVR level (sub trim) probably a little to high, the mini-dsp way to low (8 dB by your last account), and the subs (at least 8 dB) to high. Normally I wouldn't care, since it's simply your listening experience. But you are respected around these woods, and plan on documenting your experiences. So in this case, I would rather see you take some more care in gain matching your devices.
What would your ideal settings be for all three levels - AVR trim, miniDSP and sub? I plan to go the same way as Jerry, using the DDRC-88, but this is uncharted territory for me.
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post #2546 of 3189 Old 12-16-2014, 05:02 AM
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The mini-dsp will work best with it's input/output levels at maximum. Since the Rev b. has 7.5 dB of insertion loss, you should probably have it configured in Rev a. This means 0.9v input/output.

So you want the AVR outputting 0.9v maximum, so as not to clip the input of the mini-dsp. Generate some pink noise with REW at -3 dB, and the AVR main volume control at -0 dB (or whatever is your reference level). Set the sub trim on the AVR at a point where the input level meters on the mini-dsp begin to drop/raise. In other words, if the mini-dsp input meters are at 0.0dB @ -8 dB AVR sub trim, then any higher is simply clipping. Set the AVR sub trim to the point just before clipping.

Adjust sub levels as needed.

If you run Audyssey afterwards, you should double check the AVR sub trim setting. If it has been raised (ie: -3 dB instead of -8 dB as the example above), you should increase the gains on the subs.
If the AVR sub trim has lowered (say -12 dB), you should reduce the gains on the subs.

How close you maintain the input level of the min-dsp to 0 dB after all is said and done, is you're own decision on benefit/time.
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post #2547 of 3189 Old 12-16-2014, 05:41 AM
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The mini-dsp will work best with it's input/output levels at maximum. Since the Rev b. has 7.5 dB of insertion loss, you should probably have it configured in Rev a. This means 0.9v input/output.

So you want the AVR outputting 0.9v maximum, so as not to clip the input of the mini-dsp. Generate some pink noise with REW at -3 dB, and the AVR main volume control at -0 dB (or whatever is your reference level). Set the sub trim on the AVR at a point where the input level meters on the mini-dsp begin to drop/raise. In other words, if the mini-dsp input meters are at 0.0dB @ -8 dB AVR sub trim, then any higher is simply clipping. Set the AVR sub trim to the point just before clipping.

Adjust sub levels as needed.

If you run Audyssey afterwards, you should double check the AVR sub trim setting. If it has been raised (ie: -3 dB instead of -8 dB as the example above), you should increase the gains on the subs.
If the AVR sub trim has lowered (say -12 dB), you should reduce the gains on the subs.

How close you maintain the input level of the min-dsp to 0 dB after all is said and done, is you're own decision on benefit/time.
Many thanks. I will need time to digest that
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post #2548 of 3189 Old 12-16-2014, 07:07 AM
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Originally Posted by Audionut11 View Post
The mini-dsp will work best with it's input/output levels at maximum. Since the Rev b. has 7.5 dB of insertion loss, you should probably have it configured in Rev a. This means 0.9v input/output.

So you want the AVR outputting 0.9v maximum, so as not to clip the input of the mini-dsp. Generate some pink noise with REW at -3 dB, and the AVR main volume control at -0 dB (or whatever is your reference level). Set the sub trim on the AVR at a point where the input level meters on the mini-dsp begin to drop/raise. In other words, if the mini-dsp input meters are at 0.0dB @ -8 dB AVR sub trim, then any higher is simply clipping. Set the AVR sub trim to the point just before clipping.

Adjust sub levels as needed.

If you run Audyssey afterwards, you should double check the AVR sub trim setting. If it has been raised (ie: -3 dB instead of -8 dB as the example above), you should increase the gains on the subs.
If the AVR sub trim has lowered (say -12 dB), you should reduce the gains on the subs.

How close you maintain the input level of the min-dsp to 0 dB after all is said and done, is you're own decision on benefit/time.
Until your post, I was unaware that there were two revs of the MiniDSP 4x2. I checked mine, and it is indeed a Rev A. Not sure how I got a rev A because it was purchased less than 6 months ago, and I don't recall at purchase time being asked which rev I wanted. I assume as long as the proper procedure is followed, this will not be an issue.

Sorry for so many questions, but I would like to understand and follow your procedure.

- When you say generate pink noise at -3dB using REW's tone generator, do you mean set the RMS output level to -3dBFS? What is the significance of -3dB?

- If, as per your example, -8 for the AVR sub trim is the point where clipping starts, and then you run Audyssey and it sets the trims to -3, you recommend adjusting the sub gains lower, then repeating the Audyssey calibration until the trim set by Audyssey is -8 (or lower). This sounds incredibly time-consuming. It takes an hour to conduct a full Audyssey Pro calibration on my system. When you do this, do you run a quick 1-position Audyssey calibration (using the consumer mic) just to see the trim level Audyssey sets? That would save some time.

- What is not clear to me at this time is what is happening if the MiniDSP is clipping. Does this mean distortion in the sub channel? I'm not sure I would be able to tell whether my sub channel was distorting or not. And once everything is configured per your procedure, what do I look for on the MiniDSP to see if it is clipping or not? The level of the input meter?

- And in a previous post, you mention a sub level of ~72dB, which when all four subs are summed, will result in a level at the MLP of ~75dB. This leads me to believe you are level-matching the subs, not gain-matching. To me, gain-matching involves placing the mic near-field (1-2" from the speaker cone) and setting the gain. This eliminates the effects of the room, which can be significant if you are level-matching with the mic at the MLP. When setting the sub gain using what I call gain-matching, the sub levels are more likely to be in the 85-90dB range, not 72dB. While I am not sure level-matching vs. gain-matching is relevant to the overall procedure, I am curious why you use level-matching.

I appreciate your input. It is important that I get this process nailed down and documented, and I want to make sure what I am doing is correct.
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post #2549 of 3189 Old 12-16-2014, 07:18 AM
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I just checked my levels. The MiniDSP input level is set to -8. The AVR sub trim is -4. Outputting the sub level test tone from the AVR (which is at MV=0), which measures 75dB at the MLP, the MiniDSP input level meter reads -36dB, as shown below. Is there clipping?

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post #2550 of 3189 Old 12-16-2014, 08:41 AM
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- If, as per your example, -8 for the AVR sub trim is the point where clipping starts, and then you run Audyssey and it sets the trims to -3, you recommend adjusting the sub gains lower, then repeating the Audyssey calibration until the trim set by Audyssey is -8 (or lower). This sounds incredibly time-consuming.
Jerry, I am learning this stuff as I go along, so I may be off-target here but if I understand correctly, I had to do a similar exercise when adding external PEQ into my sub chain. All that I did to get into the ballpark when trying to juggle AVR sub trim level and sub physical gain control level was this:

My sub trim in the AVR was set at -3dB - this was too high for the PEQ device and it was clipping it, as indicated by the red clipping light coming on frequently and sometimes remaining on for longer than seemed prudent. So what I needed to do was to lower the sub trim in the AVR to, say, -8dB. At the same time, this would mean that I needed to add 5dB to the physical gain control on the sub, in order to maintain output level the same as before. So all I did was adjust the trim in the AVR by 5dB and then, using my calibrated mic and REW's SPL meter, adjust the gain on the sub until I had raised it by 5dB. When I re-ran Audyssey everything was spot on, because as far as Audyssey was concerned nothing had changed. Thus saved me from running Audyssey numerous times to get it right.

Of course, since I have dropped Audyssey Pro in favor of XT32 on my Denon 5200, a calibration only takes about 15 minutes now - but as you are still using Pro, the above might be helpful. Ass-u-me-ing that I am understanding, which is by no means certain at this time
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