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post #2641 of 2680 Old 12-18-2014, 09:28 AM
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Quote:
Originally Posted by wildoak View Post
Whoa Ace

If your receiver puts out 1.2V that will EXCEED the limits of the DSP's input if the jumper is set to 0.9V. I would expect the DSP input to clip on high power dynamics and that clipping would be carried through to the DSP output. You would need to set the jumper for 2.0V and adjust the amplifier gain if posible, otherwise let the receiver cal set its output to compensate.

Main thing to take away here is the AVR/Receiver output should NEVER exceed the input limit of the downstream device be it a DSP or Power Amp.


I am fully aware of that.


My receiver is set to about -5dB on my mains and subwoofers and I am hardly playing louder than -10 to -8 on Movies, only demos. Normal is about -15 to -20 which is loud enough.


I havent taken any measurements after my last calibration but I will soon to get a new reference
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post #2642 of 2680 Old 12-18-2014, 10:04 AM
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But why take the risk when proper gain stucture loses you nothing and protects you from potential damage to either your AVR or, in the case of clipping into the mains, to speakers? What's the up side?
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post #2643 of 2680 Old 12-18-2014, 10:45 AM
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The way I see it, risk is everywhere.

Say you have proper gainstructure, its still possible to toast some drivers...

The use of limiters is more safe in my opinion.
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post #2644 of 2680 Old 12-18-2014, 12:12 PM
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Fair enough.
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post #2645 of 2680 Old 12-18-2014, 04:19 PM
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1.2 v into 2v to 0.5v is far removed from correct gain structure.

What's the big deal with dialing back a pre-out level? The 2v option on the mini-dsp should only ever be thought of as, "Crap, I can't safely ensure a maximum of 0.9v out of my source".
A tiny amount of clipping into the input of the mini-dsp for subs isn't a showstopper anyway, as attested by the recent discussion.
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post #2646 of 2680 Old 12-18-2014, 06:01 PM
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Strike Ace mentioned his output from the AVR was as high as 1.2V exceeding the 0.9V input limit by 33%. There are only two choices here, not a variable adjustment, so for proper gain structure you're forced the safest setting. As long as the sub amp has an input/gain adjustment the 0.54V max output from the MiniDSP resulting from the 2.0V jumper setting is easily matched and will yield full output and SQ without the INCREASED risk. Take a look at the auto sound monoblock image below.



It's not a pro amp like an iNuke but it's the silk screening on the input sensitivity adjustment that I want to focus on. As you can see the "max input" range varies from 6V to 0.2V. This sets the gain of the amplifier so that an input of what ever the setting is will yield maximum output from the amplifier. The gain adjustment on the iNuke or other would work the same. The reduction of the signal across the MiniDSP is easily compensated at the amp yielding an ideal as possible gain structure.
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post #2647 of 2680 Old 12-18-2014, 06:06 PM
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Additionally, this ignores the fact that MiniDSP's balanced version would pass the 1.2V without attenuation.
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post #2648 of 2680 Old 12-18-2014, 10:42 PM
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Quote:
Originally Posted by wildoak View Post
The reduction of the signal across the MiniDSP is easily compensated at the amp yielding an ideal as possible gain structure.
And there is no compensation needed (nor insertion loss) at all, by adjusting the sub trim level on the AVR. 0.9 > 0.9 > 0.9.

You're sacrificing the noise floor by having the sensitivity on the sub amp set at it's maximum. Granted, this (probably) won't be noticed in normal usage, but it is far better to have as many source volts as possible running into the amplification stage.

If you're stuck at 1.2v out of the pre, I'd be all over your solution. But in this case...........

Last edited by Audionut11; 12-18-2014 at 10:48 PM.
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post #2649 of 2680 Old 12-18-2014, 11:28 PM
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Quote:
Originally Posted by Audionut11 View Post
And there is no compensation needed (nor insertion loss) at all, by adjusting the sub trim level on the AVR. 0.9 > 0.9 > 0.9.

You're sacrificing the noise floor by having the sensitivity on the sub amp set at it's maximum. Granted, this (probably) won't be noticed in normal usage, but it is far better to have as many source volts as possible running into the amplification stage.

If you're stuck at 1.2v out of the pre, I'd be all over your solution. But in this case...........
I have to admit, with my sub trim at -5, and knowing a trim of -4.5 is the .9V threshold, I am feeling pretty good about the results. And the sub channel sounds really good. Here are some measurements.

First, a comparison of the sub channel response showing the results of a two-channel Audyssey SubEQ HT calibration, and the current one sub channel using the Mini-DSP time alignment:



Distortion when using the Mini-DSP remains acceptably low:



And finally, bass resonance remains good:



Pleased so far.... (Thanks, Nut!)
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post #2650 of 2680 Old 12-19-2014, 12:56 AM
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Nice work Jerry. It's refreshing when things pan out after initial frustrations.

The next thing I would do, is work on those bumps in the waterfall that start about 15 dB down from the peak. If you have some spare EQ bands left on the miniDSP, you can try working some magic in the REW EQ wizard and see if it translates into real world results (my testing suggests that it will).

I would measure each sub separately, and see which subs are responsible for each bump. For instance, it may only be 1 of your woofers causing the bump @ 42hz. If that was the case, you could EQ just that sub, allowing the other 3 to generate maximum output at that frequency. Getting into really picky territory though, and that distortion graph is making me jealous.

It could be interesting to increase the pre-out back to +/-0 dB, measure the result and see if the input clipping on the miniDSP generates changes on the distortion graph.

Thanks for the update.
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post #2651 of 2680 Old 12-19-2014, 01:07 AM
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Quote:
Originally Posted by wildoak View Post
Strike Ace mentioned his output from the AVR was as high as 1.2V exceeding the 0.9V input limit by 33%. There are only two choices here, not a variable adjustment, so for proper gain structure you're forced the safest setting. As long as the sub amp has an input/gain adjustment the 0.54V max output from the MiniDSP resulting from the 2.0V jumper setting is easily matched and will yield full output and SQ without the INCREASED risk.

It's not a pro amp like an iNuke but it's the silk screening on the input sensitivity adjustment that I want to focus on. As you can see the "max input" range varies from 6V to 0.2V. This sets the gain of the amplifier so that an input of what ever the setting is will yield maximum output from the amplifier. The gain adjustment on the iNuke or other would work the same. The reduction of the signal across the MiniDSP is easily compensated at the amp yielding an ideal as possible gain structure.
that dial would be normally be seen on a pro amp as a gain dial that runs 0 to -30dB and I would expect the amp to be listed as having an input sensitivity of 0.2V, i.e. it divides the voltage down at the input stage. Therefore, while what you say is true in general, if the amp has an input sensitivity that is greater than the max output you can get from the minidsp then you have a problem & either need a line driver/bump box to boost the signal or rely on limiting yourself via the MV. This sounds like the situation Strike Ace is describing & since 1.2V to 0.9V is -2.5dB, it seems a reasonable tradeoff as long as you accept you can't run at MV=0. Ultimately you just need as much power as you need not all the power just because.
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post #2652 of 2680 Old 12-19-2014, 01:38 AM
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I took some measurements of my PreOuts on my Onkyo TX-NR818.


When set to -0 on MasterVolume, it did measure 2.0V!!
I do not use the rev A/0.9V Input on MiniDSP but the Rev B/2.0V input.
(sorry for the confusion)


After taking a look at the input Level on the minidsp it confirms my measurements.
It says about -0 "headroom" and when I drop 2-3dB on Master Volume, the MiniDSP gets 2-3dB of headroom before max.


I do not know where I got my 1.2Volts from but the first thing I did was to check the manual for the 818 and it says:
Rated RCA Output Level and Impedance
200mV/470 O (PRE OUT)
Maximum RCA Output Level and Impedance
4.6V / 470 O (PRE OUT)


After the measurements of my Receiver, I tried to measure the output from the MiniDSP.
A 60Hz Sinewave resulted in Max 0.5V out unclipped.


I could force the output to about 0.7-0.8V using EQ and boost the 60Hz to "sky high" but the signal starts to clip right above 0.5V and is heavily clipped at 0.7-0.8V.


To me, it does not seem like 2.0Volts in to MiniDSP unbalanced will give 0.8/0.9Volts out - unclipped.


Have someone else measured a clean unclipped signal out from MiniDSP unbalanced above 0.5Volts?
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post #2653 of 2680 Old 12-19-2014, 07:23 AM
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Quote:
Originally Posted by Strike Ace View Post

Have someone else measured a clean unclipped signal out from MiniDSP unbalanced above 0.5Volts?
Assuming it is reasonably straight-forward and doesn't cost me more money, I would be interested in taking some measurements. Perhaps you could provide a brief description of how you measure clipping?
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post #2654 of 2680 Old 12-19-2014, 07:47 AM
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Quote:
Originally Posted by AustinJerry View Post
Assuming it is reasonably straight-forward and doesn't cost me more money, I would be interested in taking some measurements. Perhaps you could provide a brief description of how you measure clipping?

I am using these Components when measuring: PC Output-> Receiver -> MiniDSP -> PC input


Use a PC and Connect the line out to the receiver (or use HDMI / Optical)
Connect the output from the MiniDSP into the line-in (not mic in)


Download Trial Versjon (or buy) software oscilloscope: http://www.zelscope.com/
You can choose to use left or right line in when measuring (or both)


Use a signal generator (I used the one in REW) to provide a sine wave. ex 100hz.
Increase MasterVolume on receiver to see how high you can og before the wave gets "clipped"
You might want to adjust the voltage scale on the sw oscilloscope so the "top" of the wave is inside the window and visible.


Set the signal as high as possible before clipping, and measure the voltage from the MiniDSP output. Take a note of voltage, Master Volume and Sub/front volume trim.
Do not use the voltage in the SW Oscilloscope if you havent calibrated it with a hardware voltage meter.
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post #2655 of 2680 Old 12-19-2014, 08:11 AM
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Oh man, my head is spinning. Is there a consensus here?

What I believe I'm coming away with is:

With my miniDSP RevB 2.0V model, the best practice would be to:

a) open it up and set the jumper back to 0.9V
b) use a multimeter to determine the max output of my AVR sub pre-out using procedure(s) previously listed
c) if necessary dial down the AVR trim to a level that reads 0.9V max when playing 60Hz at -3dB and AVR MV=0*
d) bring level back up to 72dB by using gain knob on sub

*is this assuming the signal is routed to Ch1&Ch2 relying on bass management for the sub, or is the intent to play the tone to channel 4 directly?
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post #2656 of 2680 Old 12-19-2014, 08:24 AM
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Quote:
Originally Posted by Strike Ace View Post
Have someone else measured a clean unclipped signal out from MiniDSP unbalanced above 0.5Volts?
fwiw there are quite a few threads on diyaudio that cover this, they'd be all over it if it didn't produce the rated output (though there is a thread going recently where someone is commenting is gets noisier above 0.5V - http://www.diyaudio.com/forums/minid...o-minidsp.html)

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Originally Posted by HDgaming42 View Post
Oh man, my head is spinning. Is there a consensus here?
What I believe I'm coming away with is:

With my miniDSP RevB 2.0V model, the best practice would be to:

a) open it up and set the jumper back to 0.9V
b) use a multimeter to determine the max output of my AVR sub pre-out using procedure(s) previously listed
c) if necessary dial down the AVR trim to a level that reads 0.9V max when playing 60Hz at -3dB and AVR MV=0*
d) bring level back up to 72dB by using gain knob on sub

*is this assuming the signal is routed to Ch1&Ch2 relying on bass management for the sub, or is the intent to play the tone to channel 4 directly?
I don't think you can say that is "best practice as the right answer depends on the input sensitivity of whatever is downstream of the minidsp, what levels you are aiming to produce, whether the system is for film or music, the voltage produced by the prepro (& whether they are XLR or RCA).

Last edited by 3ll3d00d; 12-19-2014 at 08:37 AM.
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post #2657 of 2680 Old 12-19-2014, 09:45 AM
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Quote:
Originally Posted by HDgaming42 View Post
Oh man, my head is spinning. Is there a consensus here?

What I believe I'm coming away with is:

With my miniDSP RevB 2.0V model, the best practice would be to:

a) open it up and set the jumper back to 0.9V
b) use a multimeter to determine the max output of my AVR sub pre-out using procedure(s) previously listed
c) if necessary dial down the AVR trim to a level that reads 0.9V max when playing 60Hz at -3dB and AVR MV=0*
d) bring level back up to 72dB by using gain knob on sub

*is this assuming the signal is routed to Ch1&Ch2 relying on bass management for the sub, or is the intent to play the tone to channel 4 directly?
That is essentially the procedure I used. When you determine the AVR trim in step 2, and if you run an Audyssey calibration afterwards, you have a balancing act to accomplish: the trim that Audyssey sets should not exceed the trim you established in step 2, and the trim also should measure 75dB at the MLP. If you want to dial-up the bass level by adjusting the trim, you need to take care not to exceed the .9V level.

Also note that I am using one output from the AVR. My experiment using the MiniDSP was specifically designed to see if I could accomplish the same quality bass output by eliminating the SubEQ HT part of MultEQ XT32. If you continue using both sub outputs, then you will need to revise the approach accordingly.
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post #2658 of 2680 Old 12-19-2014, 09:49 AM
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Quote:
Originally Posted by Strike Ace View Post
I am using these Components when measuring: PC Output-> Receiver -> MiniDSP -> PC input


Use a PC and Connect the line out to the receiver (or use HDMI / Optical)
Connect the output from the MiniDSP into the line-in (not mic in)


Download Trial Versjon (or buy) software oscilloscope: http://www.zelscope.com/
You can choose to use left or right line in when measuring (or both)


Use a signal generator (I used the one in REW) to provide a sine wave. ex 100hz.
Increase MasterVolume on receiver to see how high you can og before the wave gets "clipped"
You might want to adjust the voltage scale on the sw oscilloscope so the "top" of the wave is inside the window and visible.


Set the signal as high as possible before clipping, and measure the voltage from the MiniDSP output. Take a note of voltage, Master Volume and Sub/front volume trim.
Do not use the voltage in the SW Oscilloscope if you havent calibrated it with a hardware voltage meter.
I recall a previous post that said a Line-level input (not the Mic input) must be used. Sorry if that previous post was yours as well. Since my laptop has no line-level input, I guess this means there is no way for me to observe the sine wave for clipping. Unless someone else has a suggestion that is compatible with my hardware.
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post #2659 of 2680 Old 12-19-2014, 09:52 AM
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Quote:
Originally Posted by 3ll3d00d View Post
I don't think you can say that is "best practice as the right answer depends on the input sensitivity of whatever is downstream of the minidsp, what levels you are aiming to produce, whether the system is for film or music, the voltage produced by the prepro (& whether they are XLR or RCA).
Thanks for responding--all fair points. Perhaps you or someone else can assist me in finding the answers to the questions you've raised, and let me know if the workflow I've outlined would actually constitute the best practice--for my particular setup.

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input sensitivity of whatever is downstream of the minidsp
How would I determine this? I have an SVS-PB2000, containing a Sledge STA-500D DSP amplifier. Viewing the manual and googling for "input sensitivity" doesn't seem to provide me with anything regarding the voltage expected... I believe I understand how I could use a multimeter to take a reading directly off the AVR output, and again off the output of the miniDSP, but I don't understand how (or if) you can measure what the sub is "expecting". This should be documented somewhere, no?

Quote:
what levels you are aiming to produce
Peak, or calibration? My aim is to calibrate to 75dB, though truth be told my day-to-day listening tends to be lower. When calibrated to 75dB, I tend to run my AVR MV between -10 and 0.

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whether the system is for film or music
System has to perform double-duty, with the edge given to music.

Quote:
the voltage produced by the prepro (& whether they are XLR or RCA)
RCA. And perhaps this is where I'm not "getting it" yet. Over the past few pages, it seems as if even if your AVR produces greater than 0.9V, it is better to dial it down and set the miniDSP to 0.9V, rather than set it to 2.0V because of the way the 2.0V setting drops the miniDSPs output. But perhaps I'm mis-reading it.
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post #2660 of 2680 Old 12-19-2014, 10:13 AM
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Quote:
Originally Posted by AustinJerry View Post
That is essentially the procedure I used. When you determine the AVR trim in step 2, and if you run an Audyssey calibration afterwards, you have a balancing act to accomplish: the trim that Audyssey sets should not exceed the trim you established in step 2, and the trim also should measure 75dB at the MLP. If you want to dial-up the bass level by adjusting the trim, you need to take care not to exceed the .9V level.

Also note that I am using one output from the AVR. My experiment using the MiniDSP was specifically designed to see if I could accomplish the same quality bass output by eliminating the SubEQ HT part of MultEQ XT32. If you continue using both sub outputs, then you will need to revise the approach accordingly.
Yes, I hope to accomplish what you are doing--using a singular sub pre-out into the miniDSP to drive (eventually) three subs.

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Originally Posted by Audionut11 View Post
The 2v option on the mini-dsp should only ever be thought of as, "Crap, I can't safely ensure a maximum of 0.9v out of my source".
So assuming my AVR can trim the sub out down to below <0.9V that is the route to take, correct? Even if my out measures 1.8V, it is better to lower it than use the miniDSPs less desirable setting of 2.0V?

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Originally Posted by 3ll3d00d View Post
yes that's how I do it (measure 1 main channel + the SW)
So in an environment that will play back both movies and music, it is important to factor in the LFE 10dB when setting the AVR sub trim to <0.9V. In REW this is accomplished by driving both one main channel (CH1) and the LFE (CH4) simultaneously during the 60Hz -3dBFS test tone? Do I have that correct?
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post #2661 of 2680 Old 12-19-2014, 10:19 AM
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Quote:
Originally Posted by HDgaming42 View Post
Thanks for responding--all fair points. Perhaps you or someone else can assist me in finding the answers to the questions you've raised, and let me know if the workflow I've outlined would actually constitute the best practice--for my particular setup.
which is what?

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Originally Posted by HDgaming42 View Post
How would I determine this?
if it's not published then you'd have to ask SVS

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Originally Posted by HDgaming42 View Post
Peak, or calibration? My aim is to calibrate to 75dB, though truth be told my day-to-day listening tends to be lower. When calibrated to 75dB, I tend to run my AVR MV between -10 and 0.
peak

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Originally Posted by HDgaming42 View Post
System has to perform double-duty, with the edge given to music.
then film reference is probably the thing to calibrate to

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Originally Posted by HDgaming42 View Post
RCA. And perhaps this is where I'm not "getting it" yet. Over the past few pages, it seems as if even if your AVR produces greater than 0.9V, it is better to dial it down and set the miniDSP to 0.9V, rather than set it to 2.0V because of the way the 2.0V setting drops the miniDSPs output. But perhaps I'm mis-reading it.
I'm not aware of a reason why it makes a difference, not something I've looked into exhaustively though. In the 2V setting then 2V is "full power", in the 0.9V setting then 0.9V is full power, either way the unbalanced apparently outputs 0.9V. If your prepro puts out loads more than 2V then you probably want the higher setting, if it puts out less than 2V then you probably want the 0.9V setting & reduce the trim rather than raising the trim. Alternatively if you need more than 0.9V out then you need the balanced version.

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Originally Posted by HDgaming42 View Post
So in an environment that will play back both movies and music, it is important to factor in the LFE 10dB when setting the AVR sub trim to <0.9V. In REW this is accomplished by driving both one main channel (CH1) and the LFE (CH4) simultaneously during the 60Hz -3dBFS test tone? Do I have that correct?
you need to cater for the peak voltage that will be sent through the device, for a film system this is dominated by the LFE yes. You don't need to drive a main channel through it, you can just use the LFE channel alone (technically you'd should allow for the sum of all the channels but that arguably overkill^2)

Last edited by 3ll3d00d; 12-19-2014 at 10:56 AM.
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post #2662 of 2680 Old 12-19-2014, 11:20 AM
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FWIW (not intending the stir the pot)

I've been using a MiniDSP unbalanced for sub EQ for months.
AVR - Pioneer SC-71 - subout 2.0Vrms @-0MV with the input from Rives Audio Test CD #2 - 60hz tone (non-Radio Shack SPL meter adjusted tone group)
MiniDSP input jumper in 2.0V position. MiniDSP input and output gain @0db
Sub amp -Dayton Audio SPA-1000 LFE input

filters in force are:
Input: one PEQ to level response (as shown in the model) and one biquad for a Linkwitz Transform
Output: four PEQ for SW room EQ

MCACC set SW level @ -3db and SW trim @+2
Plate amp gain is (I believe, I'll check tonight) between 10 o'clock and 2 o'clock

Everything is fine and the sub never sounded better.
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post #2663 of 2680 Old 12-19-2014, 11:32 AM
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Quote:
Originally Posted by 3ll3d00d View Post
which is what?
currenty:
Onkyo 805 (have to measure sub output voltage)
MiniDSP 2x4 (RevB, currently 2.0V input, 0.9V output)
SVS-PB2000 (max 2V input, minimum unknown* just called them to verify)

Eventually:
Denon X4000 (have to measure sub output voltage out to 88A)
MiniDSP DDRC-88A (have to measure sub output voltage)
Onkyo 805 as amp (subs are powered and will skip over the 805)
MiniDSP 2x4 (RevB, currently 2.0V input, 0.9V output)
(3x) SVS-PB2000 (max 2V input, minimum unknown)

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I'm not aware of a reason why it makes a difference, not something I've looked into exhaustively though. In the 2V setting then 2V is "full power", in the 0.9V setting then 0.9V is full power, either way the unbalanced apparently outputs 0.9V. If your prepro puts out loads more than 2V then you probably want the higher setting, if it puts out less than 2V then you probably want the 0.9V setting & reduce the trim rather than raising the trim. Alternatively if you need more than 0.9V out then you need the balanced version.
I gravitate toward thinking much like you've described. However I get the impression others feel the 2V setting has disadvantages, but perhaps I'm reading more into it than there is...

Last edited by HDgaming42; 12-19-2014 at 11:37 AM.
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post #2664 of 2680 Old 12-19-2014, 11:52 AM
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Originally Posted by HDgaming42 View Post
currenty:
Onkyo 805 (have to measure sub output voltage)
MiniDSP 2x4 (RevB, currently 2.0V input, 0.9V output)
SVS-PB2000 (max 2V input, minimum unknown* just called them to verify)

Eventually:
Denon X4000 (have to measure sub output voltage out to 88A)
MiniDSP DDRC-88A (have to measure sub output voltage)
Onkyo 805 as amp (subs are powered and will skip over the 805)
MiniDSP 2x4 (RevB, currently 2.0V input, 0.9V output)
(3x) SVS-PB2000 (max 2V input, minimum unknown)

I gravitate toward thinking much like you've described. However I get the impression others feel the 2V setting has disadvantages, but perhaps I'm reading more into it than there is...
so your signal chain will be X4000 -> MiniDSP 2x4 -> MiniDSP DDRC-88A -> amps/subs ? and you'll have to switch the input sensitivity of the DDRC to 0.9Vrms then? this means you'll have the option of going 2V -> 0.9V -> 2V or 0.9V -> 0.9V -> 2V based on the minidsp2x4 jumper, seems like you'll be better off with the balanced 2x4 as then it would just be 2V all the way down the line.

I don't get what the 805 is doing in there btw, how will you use that?
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post #2665 of 2680 Old 12-19-2014, 12:08 PM
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Quote:
Originally Posted by 3ll3d00d View Post
so your signal chain will be X4000 -> MiniDSP 2x4 -> MiniDSP DDRC-88A -> amps/subs ? and you'll have to switch the input sensitivity of the DDRC to 0.9Vrms then? this means you'll have the option of going 2V -> 0.9V -> 2V or 0.9V -> 0.9V -> 2V based on the minidsp2x4 jumper, seems like you'll be better off with the balanced 2x4 as then it would just be 2V all the way down the line.

I don't get what the 805 is doing in there btw, how will you use that?
I'm confused. No, I expect to eventually run X4000-->DDRC-88A-->MiniDSP2x4--->3 powered subs. The 805 will only be used to power other passive speakers as an amp--ignore it for the purposes of the sub signal chain.

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Originally Posted by 3ll3d00d View Post
seems like you'll be better off with the balanced 2x4 as then it would just be 2V all the way down the line.
Agreed. But if I can make this work at 0.9V then I don't have to spend more money replacing gear I've only recently purchased.

Last edited by HDgaming42; 12-19-2014 at 12:12 PM.
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post #2666 of 2680 Old 12-19-2014, 12:14 PM
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Originally Posted by HDgaming42 View Post
I'm confused
obviously so am I as that way makes sense, mine doesn't so 2-2-0.9 then. I guess it just depends if 0.9V is enough for the SVS subs, their answer didn't seem to clarify that.
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post #2667 of 2680 Old 12-19-2014, 12:33 PM
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Originally Posted by Strike Ace View Post
I took some measurements of my PreOuts on my Onkyo TX-NR818.


When set to -0 on MasterVolume, it did measure 2.0V!!
I do not use the rev A/0.9V Input on MiniDSP but the Rev B/2.0V input.
(sorry for the confusion)


After taking a look at the input Level on the minidsp it confirms my measurements.
It says about -0 "headroom" and when I drop 2-3dB on Master Volume, the MiniDSP gets 2-3dB of headroom before max.


I do not know where I got my 1.2Volts from but the first thing I did was to check the manual for the 818 and it says:
Rated RCA Output Level and Impedance
200mV/470 O (PRE OUT)
Maximum RCA Output Level and Impedance
4.6V / 470 O (PRE OUT)


After the measurements of my Receiver, I tried to measure the output from the MiniDSP.
A 60Hz Sinewave resulted in Max 0.5V out unclipped.


I could force the output to about 0.7-0.8V using EQ and boost the 60Hz to "sky high" but the signal starts to clip right above 0.5V and is heavily clipped at 0.7-0.8V.


To me, it does not seem like 2.0Volts in to MiniDSP unbalanced will give 0.8/0.9Volts out - unclipped.


Have someone else measured a clean unclipped signal out from MiniDSP unbalanced above 0.5Volts?
I hesitate to get involved in this and my TX-NR808 -> Balanced MiniDSP 2x4 -> NU4-6000 -> subs configuration continues to work flawlessly with proper gain structure set up on the 2volt setting, but I just wanted to ask the question(s): When you were measuring the output from the Mini, did you have the "S" terminal jumped to the "+" terminal when you were measuring? And the same for the input?

Last edited by dtsdig; 12-19-2014 at 12:37 PM.
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post #2668 of 2680 Old 12-19-2014, 02:01 PM
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Quote:
Originally Posted by dtsdig View Post
I hesitate to get involved in this and my TX-NR808 -> Balanced MiniDSP 2x4 -> NU4-6000 -> subs configuration continues to work flawlessly with proper gain structure set up on the 2volt setting, but I just wanted to ask the question(s): When you were measuring the output from the Mini, did you have the "S" terminal jumped to the "+" terminal when you were measuring? And the same for the input?
I am not quite sure what you are asking for here.
When measuring, I always use the center RCA pin for + (plus) and the outer ring for - (minus) (opposite should not be any problem either)


It is the same measuring with "loose ends" or with units connected in both ends.
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post #2669 of 2680 Old 12-19-2014, 02:09 PM
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Quote:
Originally Posted by Strike Ace View Post
I am not quite sure what you are asking for here.
When measuring, I always use the center RCA pin for + (plus) and the outer ring for - (minus) (opposite should not be any problem either)


It is the same measuring with "loose ends" or with units connected in both ends.
Maybe I didn't read back far enough. You are using the MiniDSP 2x4 balanced, correct? How are you connecting your AVR to the input(s) of the Mini? RCA to bare wires into the phoenix connectors of the Mini, but do you have the "S" and "+" terminals jumped with jumper wire? Same on the Phoenix output terminals on the Mini. How are you wired from those outputs to the XLR or 1/4" inputs of your amp?
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post #2670 of 2680 Old 12-19-2014, 02:29 PM
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I just ordered a MiniDSP 2x4 Balanced in a Box today - hoping this will give me some extra headroom and clean SPL available.


I know I have much more watts to spare on my amplifiers and I hate the thought of having a critical bottleneck in my signal chain.


When using my Fronts and BassModules for larger rooms, I really need some better options too.
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