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Discussion Starter #1
I've seen some low-output threads recently and one thing I've noticed is that usually there a Crown amp involved. I'm finally setting up my MBM's and the Crown with unbalanced inputs (regardless of input sensitivity) requires max gain to even modestly keep up with my mains! Certainly nowhere near the modeling of WinISD.

However, when I put a Clean Box Pro and convert unbalanced to balanced (XLR) I can make it pound proper. Apparently the Clean Box adds +4dB to the gain.

I'm going to get an iNuke and see if this is a similar phenomenon (and return it or sell the Crown). I'm not thrilled at the prospect of having to have a Clean Box solely to pump the gain. I have a separate circuit for the HT gear so I don't need it for ground purposes.
I don't think the crown is broke.

What have others experienced or seen?
 

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I had some issues initially with mine (XLS2000), but after a fair amount of work with the MiniDSP software, I got it to be what it needs to be IMHO.
I just realized my MiniDSP 2x4 Balanced output was set improperly (4Vrms instead of 2Vrms).

Swapping that down made a big difference this weekend, but I am using a EP4000 right now, so I cant comment on if that made any differences with my Crown (but I plan to swap it back in and see).

How are you getting the signal to the MBM's v the Subs you have?
 

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Testing of the Crown amps show that they produce very near the wattage they claim. This means that when the input voltages (signal) are correct, the amp moves electrons in the same fashion that an iNuke or Crest or any other does.

If there is an issue, you know the drill for questions: What do your gain settings look like? Are you using the sub out from the receiver for the Crown MBM signal? If so, how are you wired signal-wise and speaker wise? What is that gain at? Are you using the miniDSP for MBM processing? Any sweeps for the MBMs? I didn't see any on your build thread.

You've already found a low signal voltage issue, but seem to be pointing at the amp for a signal issue of some sort.
 

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Discussion Starter #4 (Edited)
I had some issues initially with mine (XLS2000), but after a fair amount of work with the MiniDSP software, I got it to be what it needs to be IMHO.
I just realized my MiniDSP 2x4 Balanced output was set improperly (4Vrms instead of 2Vrms).

Swapping that down made a big difference this weekend, but I am using a EP4000 right now, so I cant comment on if that made any differences with my Crown (but I plan to swap it back in and see).

How are you getting the signal to the MBM's v the Subs you have?
MiniDSP 2x4 and have the jumper set to A (0.9Vrms) and the input on the Crown set to .775Vrms. I only have the unbalanced version.

Also, my initial tests were bypassing the miniDSP and going to the AVR directly.
 

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Discussion Starter #5
Testing of the Crown amps show that they produce very near the wattage they claim. This means that when the input voltages (signal) are correct, the amp moves electrons in the same fashion that an iNuke or Crest or any other does.

If there is an issue, you know the drill for questions: What do your gain settings look like? Are you using the sub out from the receiver for the Crown MBM signal? If so, how are you wired signal-wise and speaker wise? What is that gain at? Are you using the miniDSP for MBM processing? Any sweeps for the MBMs? I didn't see any on your build thread.

You've already found a low signal voltage issue, but seem to be pointing at the amp for a signal issue of some sort.
my AVR is running at +6dB on the LFE channel, I'm running the gain knobs on the Crown at near max. I'm running through a MiniDSP set to .9Vrms and have the Crown XLS2002 set to .775. I also tested bypassing the miniDSP completely.
I'm gonna run sweeps soon. I have a 1 year old and 3 year old so it's been tough. I made progress just by setting it up. Should I set the MiniDSP from the .9 to 2Vrms? Currently it allows this:

IN: 0.9Vrms / 2Vrms (jumper–selectable)
OUT: 0.9Vrms
 

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I would try that just to see. It’s also helpful to connect it up to the computer and view the software while playing back movies to see if your clipping the input or output on the mini.

Do to signal lights in your Crown seem to indicate the signal is maxing it out or not?

Ps I have a 5 year old and a two year old so I totally feel your pain lol


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my AVR is running at +6dB on the LFE channel, I'm running the gain knobs on the Crown at near max. I'm running through a MiniDSP set to .9Vrms and have the Crown XLS2002 set to .775. I also tested bypassing the miniDSP completely.
I'm gonna run sweeps soon. I have a 1 year old and 3 year old so it's been tough. I made progress just by setting it up. Should I set the MiniDSP from the .9 to 2Vrms? Currently it allows this:

IN: 0.9Vrms / 2Vrms (jumper–selectable)
OUT: 0.9Vrms
If you are able to up the output voltage from the miniDSP, I would try that for sure. Just be careful the first time you listen like that, you might find your output has changed significantly, especially if the AVR signal is boosted a fair bit.

Are you running one unbalanced line per channel of amplification or using the Y feature of the Crown to split the signal for each channel?

Edit: @EndersShadow, are you reading my keystrokes and posting 3 minutes earlier lol. Too funny:p
 

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He can’t increase the output voltage, only the input.

The unbalanced only does .9VRMS out but can accept .9 OR 2 VRMS in


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Discussion Starter #9
I would try that just to see. It’s also helpful to connect it up to the computer and view the software while playing back movies to see if your clipping the input or output on the mini.

Do to signal lights in your Crown seem to indicate the signal is maxing it out or not?

Ps I have a 5 year old and a two year old so I totally feel your pain lol


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I have the software running so I can see what is going out and in the MiniDSP, I'm currently running it flat. I don't listen above -15dB (realistically -20dB) and I tested at -20dB with Prometheus where the ship and the waterfall are rumbling (at like 4min). I can't get it to clip at those volumes with the Clean Box at max and the gain at about 80%. I can barely get the drivers to move without the cleanbox.

I haven't ran it red but with the clean box it gets up there, without it, it comes no where near close.

I have 2 other subs (Rythmiks) coming off the miniDSP that are running fine at the current fixed output of the MiniDSP.
 

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Discussion Starter #10
If you are able to up the output voltage from the miniDSP, I would try that for sure. Just be careful the first time you listen like that, you might find your output has changed significantly, especially if the AVR signal is boosted a fair bit.

Are you running one unbalanced line per channel of amplification or using the Y feature of the Crown to split the signal for each channel?

Edit: @EndersShadow , are you reading my keystrokes and posting 3 minutes earlier lol. Too funny:p
1 per channel (no splitter). I've tried multiple cables too just in case. I also tried multiple outputs on my miniDSP to see if that was an issue. My Rythmiks haven't had issues with the current output either. I also bypass the miniDSP and had the same issue. I'll try bypassing the miniDSP completely that again tonight (or ASAP...).
 

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Where do the MBMs cross to your mains, and your subs?


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Discussion Starter #12
Where do the MBMs cross to your mains, and your subs?
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I turned the crossover off on the Crown for testing. I have the AVR set to LR at 100Hz, C at 80Hz.
 

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There must be a signal issue somewhere along that path. Maybe filters like Enders is alluding to. I'm able to get the signal lights on my XLS1502 to the red with the only the sub out from my Denon 4200w. I was able to get good output (but not thoroughly tested) from my old Yamaha 5.1 receiver. All this with the .775v input sensitivity setting on the Crown of course. The connected subs and impedance loads are nothing like the MBMs, so I'm leaving output off the table. What do the LEDs on the Crown do when you are at -20db or -15db?
 

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There must be a signal issue somewhere along that path. Maybe filters like Enders is alluding to. I'm able to get the signal lights on my XLS1502 to the red with the only the sub out from my Denon 4200w. I was able to get good output (but not thoroughly tested) from my old Yamaha 5.1 receiver. All this with the .775v input sensitivity setting on the Crown of course. The connected subs and impedance loads are nothing like the MBMs, so I'm leaving output off the table. What do the LEDs on the Crown do when you are at -20db or -15db?
Yes, I'm trying to understand the chain. The MBM's would need some sort of highpass (in the MiniDSP).

Can you take screenshots of the different MiniDSP setting screens so we can see whats up? I'm wondering if the crossover (in the Mini) is engaged and screwing with things.....

Anyway some screenshots would help a bit.

All that said, even with my "incorrect" settings in my Mini, I was able to get the Crown XLS signal lights to red and pound the stuffing out of a UM18 and also 4 CS1214 in a box.
 

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Discussion Starter #15
There must be a signal issue somewhere along that path. Maybe filters like Enders is alluding to. I'm able to get the signal lights on my XLS1502 to the red with the only the sub out from my Denon 4200w. I was able to get good output (but not thoroughly tested) from my old Yamaha 5.1 receiver. All this with the .775v input sensitivity setting on the Crown of course. The connected subs and impedance loads are nothing like the MBMs, so I'm leaving output off the table. What do the LEDs on the Crown do when you are at -20db or -15db?
I'll get some video together to confirm everything. I'll check from the sub out by itself, capture the settings crown, capture the settings from the AVR. This is all without the CleanBox correct?
 

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Discussion Starter #16
Yes, I'm trying to understand the chain. The MBM's would need some sort of highpass (in the MiniDSP).

Can you take screenshots of the different MiniDSP setting screens so we can see whats up? I'm wondering if the crossover (in the Mini) is engaged and screwing with things.....

Anyway some screenshots would help a bit.

All that said, even with my "incorrect" settings in my Mini, I was able to get the Crown XLS signal lights to red and pound the stuffing out of a UM18 and also 4 CS1214 in a box.
I have the crossovers turned off on the amp and the miniDSP. I'm using the miniDSP as a glorified splitter to turn my single sub out to a quad sub output.
I'll definitely get some pics.
 

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I'll get some video together to confirm everything. I'll check from the sub out by itself, capture the settings crown, capture the settings from the AVR. This is all without the CleanBox correct?
Yes, remove the Cleanbox and lets look at the MiniDSP screens. Depending on what plug-in you are using you might be able to upload the settings file here and I can download and take a look for myself (assuming we are both using the same plug-in).

Since you are using all 4 outputs, we need to look at the crossover and filter section of each channel, in addition to the top level settings.

Also we will want to know what you tuned your cabinets to as you VERY MUCH want to add a high pass PEQ filter on the MBM's at or a HZ or two below that to ensure you dont blow the MBM's.

IIRC the "high pass" filter would be set in the "Crossover" section in this screenshot. You'd need to set 2, one for each sub, unless your using the internal Y splitter function on the crown and then you'd just need to do it on the single channel of the Mini.



PS you will want to add the highpass BEFORE DOING ANY HIGH LEVEL TESTING. Your MBM's since they are ported (IIRC) are NOT gonna like frequencies lower than their tune, especially if your maxing out the gain on the Crowns. If you dont, you very much risk blowing them.
 

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Discussion Starter #18
Yes, remove the Cleanbox and lets look at the MiniDSP screens. Depending on what plug-in you are using you might be able to upload them here and I can take a look for myself (assuming we are both using the same plug-in).

Since you are using all 4 outputs, we need to look at the crossover and filter section of each channel, in addition to the top level settings.

Also we will want to know what you tuned your cabinets to as you VERY MUCH want to add a high pass PEQ filter on the MBM's at or a HZ or two below that to ensure you dont blow the MBM's.

IIRC the "high pass" filter would be set in the "Crossover" section in this screenshot. You'd need to set 2, one for each sub, unless your using the internal Y splitter function on the crown and then you'd just need to do it on the single channel of the Mini.



PS you will want to add the highpass BEFORE DOING ANY HIGH LEVEL TESTING. Your MBM's since they are ported (IIRC) are NOT gonna like frequencies lower than their tune, especially if your maxing out the gain on the Crowns. If you dont, you very much risk blowing them.
If that's raising a low shelf, wouldn't I want to implement a High Pass on the miniDSP (4th order at 35Hz)?
 

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I have never had any issue with Crown amps. I have ran them from a Denon X4000 and currently a Marantz SR6012 with zero issues. With the exception of 2/6 subs, my entire 7.1 system is powered by crown. I have 3 XLS1500s and an X4000 for Sub duty. In fact, I recently discovered that, in order to prevent clipping the MiniDSP HD, I had to change the input sensitivity to 4Vrms AND turn the subs down in my AVR to -10 to have adequate headroom when playing at reference level.

If you're expecting the subs to clip at -20 on the MV, you're probably going to need to do some serious EQ in the Mini to get that sort of output. If you're using a MiniDSP2x4 unbalanced with an output of 0.9Vrms, and your crown is set to .775 sensitivty, then your MiniDSP will drive your amp to and past the point of clipping given an adequate input signal.

I would suggest connecting your laptop to the MiniDSP and watching the input levels while running your clips. Watch the graphic display to see how much of an input signal your MiniDSP is receiving. Any decent AVR should have no trouble outputting the necessary 0.9V to fully drive the MiniDSP.
 

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Discussion Starter #20
I have never had any issue with Crown amps. I have ran them from a Denon X4000 and currently a Marantz SR6012 with zero issues. With the exception of 2/6 subs, my entire 7.1 system is powered by crown. I have 3 XLS1500s and an X4000 for Sub duty. In fact, I recently discovered that, in order to prevent clipping the MiniDSP HD, I had to change the input sensitivity to 4Vrms AND turn the subs down in my AVR to -10 to have adequate headroom when playing at reference level.

If you're expecting the subs to clip at -20 on the MV, you're probably going to need to do some serious EQ in the Mini to get that sort of output. If you're using a MiniDSP2x4 unbalanced with an output of 0.9Vrms, and your crown is set to .775 sensitivty, then your MiniDSP will drive your amp to and past the point of clipping given an adequate input signal.

I would suggest connecting your laptop to the MiniDSP and watching the input levels while running your clips. Watch the graphic display to see how much of an input signal your MiniDSP is receiving. Any decent AVR should have no trouble outputting the necessary 0.9V to fully drive the MiniDSP.
I’m not expecting it to clip, I’m expecting them to not be outperformed by my mains. There’s very little bass without that cleanbox.

I’ll get a video of the miniDSP input/output and show what’s going on with the Crowns output meter. I’ll be sure that the miniDSP has all crossovers bypassed and the crown is set to .775
 
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