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post #2971 of 2983 Old Yesterday, 12:03 PM
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Originally Posted by Stereodude View Post
I'm suggesting they make an in between product that's well suited for subwoofer usage that isn't $500.
I don't disagree with the importance of knowing the limits of your system but I'm curious as to why you don't just turn the trims down? are you getting too much noise if you do or can't turn it down far enough? or something else maybe?
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post #2972 of 2983 Old Yesterday, 12:25 PM
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Originally Posted by 3ll3d00d View Post
I don't disagree with the importance of knowing the limits of your system but I'm curious as to why you don't just turn the trims down? are you getting too much noise if you do or can't turn it down far enough? or something else maybe?
With my Pioneer Elite SC05 I could just barely get the output voltage below the clipping point of the balanced 2x4 by turning the sub trim down to -10dB (lowest it would go) to support 0dB / "reference" level playback of worst case 5.1 content. However, any EQ boost in the miniDSP would result in clipping the output of the miniDSP. That can be mitigated by turning down the input level in the miniDSP GUI. Then I had to turn up the gain on my amps all the way so the 75dB test tone was the right volume. So, yes, I was able to make it work, but the user has to be very cognizant of exactly what needs to be done and it's not something a n00b is going to stumble into. In it's current incarnation it's certainly not a plug & play / can't mess it up subwoofer EQ.
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post #2973 of 2983 Old Yesterday, 12:29 PM
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Originally Posted by Stereodude View Post
Why thank you. Yes, I am trying to be cheap about it. I'm suggesting they make an in between product that's well suited for subwoofer usage that isn't $500.
First, the subwoofers only clip in case of a not-gonna-happen scenario you imagined and/or completely inept system setup.

What you fail to understand is, to get the upper bass really right in a small room one actually needs the 8x8/10x10 (“8x8” for the rest of this post) unit’s capabilities anyway. (Or the 2x8/4x10 with an upstream A/D converter.) This has nothing to do with picayune complaints that a very inexpensive box can’t handle massive and not-seen-in-a-competently-set-up-system input levels. Rather, it’s the matrix routing feature that’s key.

Bass management is always handled ineptly by AVRs and prepros, and the errors are readily unmasked in competently set-up multisub installations, because the overall response is much smoother. Also, common setups put a “crossover” right in the middle of the modal region (i.e. ca 80Hz) which is just a stupid thing to do.

The way around the stupidity of onboard bass management is defeat it entirely for the mains and feed the LCR+LFE preouts to the 8x8. (One can also, of course, add the side surrounds to that, depending on how many subs one is running.) Sum all the bass from the front three channels and the LFE for the subwoofers. Apply highpass filters to your mains if you must, i.e. if they’re compromised designs (fairly small, vented, etc.), but otherwise let them run fullrange. Optimize according to your priorities (seat-seat consistency, listening position FR, whatever) using measurements.

As the 2x4 doesn’t have 4 inputs (for LCR+LFE) or enough outputs for LCR + multisubs, it’s suboptimal for serious subwoofer setups to begin with. It’s great for multiway mains, though. And would be better if they fixed its only real flaw (the turn on/off thump).

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post #2974 of 2983 Old Yesterday, 12:30 PM
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Quote:
Originally Posted by Stereodude View Post
With my Pioneer Elite SC05 I could just barely get the output voltage below the clipping point of the balanced 2x4 by turning the sub trim down to -10dB (lowest it would go) to support 0dB / "reference" level playback of worst case 5.1 content. However, any EQ boost in the miniDSP would result in clipping the output of the miniDSP. That can be mitigated by turning down the input level in the miniDSP GUI. Then I had to turn up the gain on my amps all the way so the 75dB test tone was the right volume. So, yes, I was able to make it work, but the user has to be very cognizant of exactly what needs to be done and it's not something a n00b is going to stumble into. In it's current incarnation it's certainly not a plug & play / can't mess it up subwoofer EQ.
Few units rarely are. You can argue something like the old ED eq.2 is foolproof, but just about any robust EQ setup can be botched. I know Bosso was speaking of several occassions where he saw folks using the bassis units with upwards of 18dB shelving and frying drivers, amps, and everything left and right, having no clue why it was happening. EQ is a fickle beast, you gotta definitely be "Cognizant" to say the least...

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post #2975 of 2983 Old Yesterday, 12:49 PM
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Quote:
Originally Posted by DS-21 View Post
Bass management is always handled ineptly by AVRs and prepros, and the errors are readily unmasked in competently set-up multisub installations, because the overall response is much smoother. Also, common setups put a “crossover” right in the middle of the modal region (i.e. ca 80Hz) which is just a stupid thing to do.
Just as a matter of curiosity, how high are you able to set the LPFs of the subs before you notice localization? Are they 4th-order LPFs?
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post #2976 of 2983 Old Yesterday, 03:16 PM
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Never paid any attention to this very much. But after reading Bosso's post on another forum concerning Interstellar's soundtrack, I checked my inputs. I'm using the UnBal 2x4 with whatever the jumper comes set at factory. At -10 to -8db the input clips with the 2:18min content. I haven't metered the voltage out of the preamp yet except with a -20db@50hz tone which hit 0.9v at a MV of +3db. I can't remember if Audyssey was on or off. My current amps are rated for full power@1.0v. I assume moving the jumper being moved to the 2.0v tap would give me additional headroom on the preamp side?
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post #2977 of 2983 Old Yesterday, 04:11 PM
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^
From the updated manual PDF file, page 37:
Quote:
Note that the input sensitivity jumper setting does not affect the maximum output signal – it is always 0.9 V RMS. Therefore, when the jumper is in the 2.0 V position, the miniDSP (without any other processing enabled) has an approximately 7 dB insertion loss. If higher output signal levels are required, then the miniDSP Balanced 2x4 or the 4x10 Hd can be used.
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post #2978 of 2983 Old Today, 11:09 AM
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Okay, time for a small piece of crow. If you have a Denon, or at least a 4520CI, you don't need to worry about the balanced 2x4 MiniDSP input clipping because the 4520CI subwoofer output clips just before the miniDSP will clip the input. This is a -0.01dBFS 40Hz signal encoded into the LFE channel of a 5.1 DTS file with the MV at 0dB. The 5 main channels are silent. Before making any measurements I turned off Audyssey, set all the speaker & sub trims to 0dB, and set all the speakers to the same distance.



Dialing back the master volume to -1dB eliminates the clipping.



I can also confirm that the meters with the v1.10 2 way advanced are now effectively peak readings, not RMS. The unit clips at 0dB on the internal meters. The level meters in the GUI are also now actually dB.

With that signal from the Denon fed into the balanced 2x4 MiniDSP (via an unbalanced connection) the input levels show this:



The output levels for the same signal (no filters active):

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post #2979 of 2983 Old Today, 03:55 PM
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Good to know. That is the exact avr that I am using. I have used it with yamaha's and other Denons too without issues. Thanks for taking the time to do the test.
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post #2980 of 2983 Old Today, 05:16 PM
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Quote:
Originally Posted by andyc56 View Post
Just as a matter of curiosity, how high are you able to set the LPFs of the subs before you notice localization? Are they 4th-order LPFs?
I can't really answer that as I haven't tried to push things high enough to get localization problems. But I don't have localization issues - once I added some blu-tack to the back of the lightswitch plate near the nearfield sub, at least! - with the following settings (IIRC):
left and right subs highpassed at 160ish Hz, 2nd order,
corner sub highpassed at 120Hz, 4th order but with some odd EQ from 100-120Hz that helps smooth out the system response,
the nearfield sub highpassed at 90Hz, 4th order.

Electrical slopes are basically the electrical slopes, because the drive-units I use are pretty good up to above 1kHz.

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post #2981 of 2983 Old Today, 05:50 PM
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Thanks!
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post #2982 of 2983 Old Today, 06:24 PM
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Originally Posted by Pain Infliction View Post
Good to know. That is the exact avr that I am using. I have used it with yamaha's and other Denons too without issues. Thanks for taking the time to do the test.
Well my post wasn't to imply everything was rosy. It's just that the 4520CI clips just before the balanced 2x4 miniDSP does. The problem there is that the 4520CI clips with the SW trim at 0 and the MV at Reference (0) with only a full amplitude LFE signal (no bass redirection going on). So, if you want to listen at reference with your 4520CI you'd better have your SW trim set no higher than -5dB (to allow for some bass management + full amplitude LFE). If you want to push beyond reference for every dB above reference you want to go, you'd need to take a dB off the SW trim and make it up for it on your sub amp's gain. Unfortunately, you're limited to -12dB on the SW trim, so that means if you want to run demos above +7dB you're probably going to get some clipping from the 4520CI on the LFE channel(s).
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post #2983 of 2983 Unread Today, 07:59 PM
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I didn't know that about the 4520. I am still in the clear though because my sub trim is way down to -6.5 or so. I like to turn the amp gains up more than turning up anything else in the chain, as it should be that way anyway. I also don't watch at reference levels or near it.

Last edited by Pain Infliction; Today at 08:04 PM.
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