Brickwall Limiter

[chjade84]

Searching for overvoltage protection for my MCM driver, I was reading about limiters and ran across this guy:

Behringer MDX1600 2 channel expander/gate/compressor/peak limiter

http://www.behringer.com/EN/Products/MDX1600.aspx

The specs sheet says...

Peak Limiter Section:
Type: IGC
Level: Variable (0db to OFF)
Ratio: infinity:1
Level 1 limiter Type: clipper
Attack: "zero"
Release: "zero"

That seems like it would do the trick to keep the voltage low enough to be safe. Any thoughts? For $100 it seems a little cheap, but I don't want to spend more than I need to.

[el_ingeniero]

Searching for overvoltage protection for my MCM driver, I was reading about limiters and ran across this guy:

Behringer MDX1600 2 channel expander/gate/compressor/peak limiter

http://www.behringer.com/EN/Products/MDX1600.aspx

The specs sheet says...

Peak Limiter Section:
Type: IGC
Level: Variable (0db to OFF)
Ratio: infinity:1
Level 1 limiter Type: clipper
Attack: "zero"
Release: "zero"

That seems like it would do the trick to keep the voltage low enough to be safe. Any thoughts? For $100 it seems a little cheap, but I don't want to spend more than I need to.

That looks like something you put on a vocal mic, not something that goes between mixer and amp. You might try the UltraMizer Pro DSP1424P instead. I see it all over the place at $99.00. Make sure you can send it back if you don't like it. Doesn't look like it's a winner for Behringer the way the DCX 2496 is.

[SeisTres]

You can use it for both, mic's and line outputs, just set the settings appropriately for each and it'll work.

However, i've tried the multiple units for processing and it's old REAL quick. If you already have everything else, i guess then this would be the only reason to go this route, but if not, I recommend you save up for a dbx drpa or something similar.

But yes, it will limit.

[chjade84]

Yea, I already have everything else (for now) so this is the last thing that I'd need. I got the MDX 2600. It's not an ideal solution, but all I need it for is it's limiting function. Maybe I'll find something to do with all the other features someday.

It's a shame the plate amps don't have the limiting functions built in.

[SeisTres]

Yea, I already have everything else (for now) so this is the last thing that I'd need. I got the MDX 2600. It's not an ideal solution, but all I need it for is it's limiting function. Maybe I'll find something to do with all the other features someday.

It's a shame the plate amps don't have the limiting functions built in.

The good ones do. What are you using? and if you already have a compressor/limiter, why not take it to the highest setting and see how that works. Even my drpa doesn't have brickwall limiters. You just learn to work with them.

[chjade84]

Yea, I already have everything else (for now) so this is the last thing that I'd need. I got the MDX 2600. It's not an ideal solution, but all I need it for is it's limiting function. Maybe I'll find something to do with all the other features someday.

It's a shame the plate amps don't have the limiting functions built in.

The good ones do. What are you using? and if you already have a compressor/limiter, why not take it to the highest setting and see how that works. Even my drpa doesn't have brickwall limiters. You just learn to work with them.

I have the Foster WF-100k plate amp.

I don't have anything besides the Foster and an Onkyo Receiver. I'll listen to music or put on a movie and even with the bass at +0db on the receiver and the amp at about 50% power, the output voltage of the amp can jump past 20-24V during heavy bass hits or explosions/crashes in the movie - which, from what I've been told is bad for the MCM 8" driver.

So without the limiter I need to keep the bass turned down far too low to keep any peaks from reaching the 21V limit of the driver.

[Bill Fitzmaurice]

On the cheap for $100 this one's unbeatable:
http://eshop.macsales.com/item/Alesis/3 ... productads

One really nice unit is the DBX 160, not cheap new, but very reasonable used.

[chjade84]

Well damn, I already bought the MDX2600. It seems to do the same stuff though so it'll be fine. I like the looks of that one better though.

[SeisTres]

oooooooohhhh, I thought this was for a pro sound rig. Make sure you have your signals correctly set up for the amp. My brother has been running this exact set up (TT, foster) in a home theater setting and has never had any problems without a limiter. And he does run it pretty hard. He even asked how much was the driver in case he turned up too loud and since it's really cheap, he abuses readily.

[chjade84]

Well the driver is cheap, but how you get it out of the TT is the hard part. I even put mine in before I put the side panel on and it still was a PITA to get to a couple of the bolts. I can't imagine swapping it out once that side is on.

Either way I'd like to not blow it, and I've gotten 25V coming out of the amp easily in many situations where I'm happy with the bass output during normal scenes (10-15V), then a plane crashes and it jumps (25V+) for a couple seconds and sounds a bit distorted. Maybe that's not a big deal? But I was under the impression that the TDP for the MCM 8" driver was 21.somethingV and not to exceed that.

Am I wrong?

[Bill Fitzmaurice]

But I was under the impression that the TDP for the MCM 8" driver was 21.somethingV and not to exceed that.

Am I wrong?

21v is about 100 watts for a 4 ohm coil, so I wouldn't go higher.

[chjade84]

Well I got it all hooked up. Took a while since the instruction manual is somewhere between useless and unhelpful - at least for someone with no experience with these things. It's working pretty well to eliminate peaks in the signal, although I was somewhat surprised it seems based more on limiting the peaks relative to the signal strength rather than an absolute value. Still... it sounds better going through the compressor than not. There's less "boominess" and distortion when the bass hits hard.

The only problem... the unit introduces a ground loop hum - and a pretty annoying one at that. Right now I have a cheater plug on it which has taken care of the problem but isn't ideal. Any suggestions? Putting it on another circuit isn't an option.

[Bill Fitzmaurice]

The only problem... the unit introduces a ground loop hum - and a pretty annoying one at that. Right now I have a cheater plug on it which has taken care of the problem but isn't ideal. Any suggestions? Putting it on another circuit isn't an option.

http://www.rane.com/note110.html

[chjade84]

Thanks for the link. It was a good read.

Unfortunately, I didn't see anything that will help me with my particular problem. The cables don't seem to be at fault - as simply plugging in the compressor causes the hum to start, even when no audio cables are connected to it. That article does make me wonder how the box is grounded though... I wonder if it's grounded improperly inside...

I'm not sure I should be modifying that, though.

[Bill Fitzmaurice]

The cables don't seem to be at fault - as simply plugging in the compressor causes the hum to start, even when no audio cables are connected to it.

If you can hear hum there must be cables, because if there are no cables then the compressor output is not connected to the amplifier input.