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Discussion Starter #1
I have a 3000DSP and I will be running it in Dual Mono. I noticed yesterday it has a separate gain for ch. A, B. I also noticed on the software screen it has an input and output meter. I set the gain on my amp by playing a bass heavy track and adjusted the gain on the front panel till it starts to clip then backed it off one notch. Is this okay and I am only asking based on seeing the second gain setting on the software screen. Is there a more preferred way of setting the gain ?
 

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When you set it for Dual Mono it will have 2 seperate gains/PEQ's/DEQ's/Crossovers etc....
You can Channel Link the 2 if ya like.
I'd say have the output meters display higher than input, you don't want the input to clip the signal, as clipping the input just leads to distortion.
The gain setting in the Crossover is the output, the front knobs are the input sensitivity.

I personally run the front/Input sensitivity at ~2 o'clock, and have the output gain at 5DB, but I'm not powering 2 HT18's...yet.
 

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Discussion Starter #3
By the way how is your projects coming? Anyway the input is set around 2 as you suggested ( at least that is where its been set for awhile by me ). On the output nothing has been set so it is currently at zero. So it is okay to turn it up to 5 or should I go a little lower?
 

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Like I said, I set mine to 5db, and then used REW/UMIK-1 to run sweeps and set the levels to match my Mains, you can use an SPL meter if that's all you have, but it won't be as accurate- especially down low.
Once I figured out the levels, I used my Denon AVR to adjust the level if I needed/wanted more/less at a particular moment, I just wrote down what the level was, and can go back there at any time.

You have 2xHT-18 in Cubes IIRC, you can go higher.
I limited my 3K to [email protected] 2ohms, because I'm only running 2 MFW15 drivers, which are only rated at 225W each.
Just try to make sure the input is no higher than the output on the meters, and you can figure out the loudness per your preference.

The HT18's are waiting, don't really have a need for them at this moment. Waiting on warm weather to finish the MFW Micros, and the DIYSG 10" Pures I just ordered Tuesday night haven't shipped yet....hopefully it'll warm up good soon!
 

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BTW, did you setup the Butterworth 12 db High Pass filter on the crossover tab?
 

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Discussion Starter #6
I will play around with it later but for now I set the output to 4 it did make a difference. I also noticed both I/P and O/P meters are more closely matched now.

I probably should not mention this but here in Richmond Va we have already had one day in the 70's several in the low 60's of course this week its in the 50's. If your winter was anything like northern NY ( we have a cottage near Watertown NY ) spring cannot get here soon enough for you.:)
 

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Discussion Starter #7
BTW, did you setup the Butterworth 12 db High Pass filter on the crossover tab?
Yes that was the first thing I set. Right now I am in the process of redoing the first sub. Sanding the Restore 10X stinks ( what a mess ) but once I get it nice and smooth it will be repainted with the 4X. All I have left is to order the second sub and attach the cable everything else is ready.
 

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We've had a few decent 45-55 degree days in the last 2 weeks, but we're back to cold right now...it's 22* here right now- WC of 10*.....
It'll be warm here soon( I keep telling myself!), although we're supposed to get 2-4" Friday Night into Saturday....

Did you set the high pass filter yet? Leave the Low Pass filter on the right to OFF
 

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Discussion Starter #9
Yes HPF is set LPF off. From what I can tell even though the Cube is tuned to 20hz ( per Marty FAQ ) I have found on You Tube a test tone that goes from 2khz to 1 hz. It seems with my sub it will play to right about 16-15hz ( when it goes below 20 things go nutty doors furniture start vibrating ) below the sub is moving but cannot hear anything. Wait till you get your 18's built!!
 

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I see you are running them at 2ohms, at around 1040w per channel in stereo per specs( which are INFLATED), have you though about running the cabs in series for a 4 ohm load and bridging the amp for less stress on the amp?

Lots of folks say the output wattage is inflated, and 2ohms is tough on it, needlessly.

Just a thought.
 

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Discussion Starter #11
Given the amp spec.'s are inflated if I were to run the amp in bridged mode the most I could get out of the amp is 1100 + or -. There are plenty of people Donny included as well as LTD02 that suggest the 2 ohm load, I agree it is pushing the amp but I look at it if you had a car that is designed to go 200mph and you drove it that fast all the time you would kill it. Yes I play the music loud but as it stands w/ just one sub playing at half volume is about all I can take. Most of the time I very rarely ever see the red clipping light flicker on.
 

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Yes HPF is set LPF off. From what I can tell even though the Cube is tuned to 20hz ( per Marty FAQ ) I have found on You Tube a test tone that goes from 2khz to 1 hz. It seems with my sub it will play to right about 16-15hz ( when it goes below 20 things go nutty doors furniture start vibrating ) below the sub is moving but cannot hear anything. Wait till you get your 18's built!!
Room Gain
 

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I see you are running them at 2ohms, at around 1040w per channel in stereo per specs( which are INFLATED), have you though about running the cabs in series for a 4 ohm load and bridging the amp for less stress on the amp?

Lots of folks say the output wattage is inflated, and 2ohms is tough on it, needlessly.

There wouldn't be any difference. When bridged with a 4-ohm load, each channel is still performing exactly the same as it does separately with a 2 ohm load.
 

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There wouldn't be any difference. When bridged with a 4-ohm load, each channel is still performing exactly the same as it does separately with a 2 ohm load.
I'm not referring to output, I'm referring to less stress on the amp.

That is all.
 

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How is that?
1 presents a 2x2 ohm load to the amp, the other a 4 ohm load to the amp.
Are you sure of this?
 

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How is that?
1 presents a 2x2 ohm load to the amp, the other a 4 ohm load to the amp.
Are you sure of this?
YUP.


Bridged is the same to the amp as running stereo at half the ohm load. There are some subtle differences, but basically the same.


That's why an amp is rated as stable to 4ohm bridge or 2ohm stereo. Or 8ohm bridge/4ohm stereo.


It's also why the power goes up by more than double if you compare 1 stereo channel to two channels bridged with both having the same ohm load.
 

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Discussion Starter #18
Regardless the way it is wired right now is each sub is wired in parallel 2ohms to each channel. I am going to use the dual mono configuration of the amp. Each channel has its own settings. Unless I am reading it wrong in theory the amp will put out 1050wpc. It also seems I could have left it in bridged mode using CH.A and each sub wired in series using the bridged configuration I would only have to add one set of settings for both amps. So each way seems to be okay, just to clarify the way to set the gain I/P around 2pm O/P not sure but I have mine set at 4db. I also have the limiter set at 1024 ( I do not think setting it at max is a good idea? ) so is it correct?
 

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I thought I read the 3K was "OK" at 2 ohms, but not ,or something like that.

When bridging the channels internally, does it not omit the 2 ohm load/Lower resistance per channel/Load to the amp?

Am I over thinking this for certain?

I would have thought that internal bridging, and running off 1 channel only(technically) it would be better at 4 ohms TOTAL load, instead of 2 separate 2 ohm loads.

Thanks
 

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I think the key piece is that when you run an amp bridged @ 4 ohms, each channel is "seeing" a 2 ohm load. I had a hard time getting my head around it until I did some reading on Bill Fitzmaurice's site, he is very anti-bridging and I was trying to understand why. His rationale is you should only bridge if you need voltage swing to drive your driver to displacement, it's not about power. I don't pretend to understand all that, but I did pick up on the 4 ohm bridged = 2 ohm per channel load while reading.

I'm not qualified enough to speculate if 4 ohm bridged is easier on an amp than 2 ohm stereo, but I'd suspect it's shades of grey.
 
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