Do PA's compress?

relic245

I'm using a tonex pedal direct into the PA. 

At home I use a SubZero powered monitor to play through. I've set up a JCM 800 capture sound which sounds ace and I can do everything from the volume control on the guitar. 

Volume on 1 - very clean sound
Volume on 4 light crunch and quite a bit louder than clean
Volume on 10 - as crunchy as I ever go and a lot louder than volume on 4, which is perfect as my dirtiest sound is always louder to help it cut through.

Went to rehearsals last night and through the PA there was almost no volume difference between 4 and 10 on the guitar which made it unusable and had to revert to my old way of 3 different patches set up. 

To me that implies that the sound is getting compressed - can that be happening, or am I amagining it? 

The pa at rehearsal is a very old studio craft powered mixer.  I tried turning the gain on the mixer down incase it was set to high but didn't make any difference. 

maltingsaudio

Depends obviously but yes there are usually limiters on the outputs of PA’s which are basically a compressor set to a ratio of infinity. The input gain of a channel if set low will reduce the signal going into it acting in a limiting sort of way too, the gain on the channel should be set so your loudest noise gives about 0db on the meter so again if the channel isn’t getting enough signal it won’t sound good, set the levels so nothing turns red and you should be fine

Musicwolf

There could be compression / limiting on the PA but it may be a combination of various factors.

Your powered monitor may well claim to be FRFR, but it won't be.  Neither will the PA, so what you are hearing home vs rehearsal room will be different (plus the acoustics of the room).  When you practice at home are you using backing tracks?  If it's just your guitar then changes in volume are going to perceived very differently as, in a band mix, there will be competition at certain frequencies.

Finally, how does the overall volume compare?  If you are generally louder in the rehearsal room then the changes in guitar volume will be less pronounced.

I use modellers live.  I do my home practice with backing tracks / recordings of the rest of the band.  I tweak patches endlessly in my home studio listening on Neumann monitors and quality headphones - then I still have to make final adjustments when I play through the PA.

relic245

Musicwolf said:

There could be compression / limiting on the PA but it may be a combination of various factors.

Your powered monitor may well claim to be FRFR, but it won't be.  Neither will the PA, so what you are hearing home vs rehearsal room will be different (plus the acoustics of the room).  When you practice at home are you using backing tracks?  If it's just your guitar then changes in volume are going to perceived very differently as, in a band mix, there will be competition at certain frequencies.

Finally, how does the overall volume compare?  If you are generally louder in the rehearsal room then the changes in guitar volume will be less pronounced.

I use modellers live.  I do my home practice with backing tracks / recordings of the rest of the band.  I tweak patches endlessly in my home studio listening on Neumann monitors and quality headphones - then I still have to make final adjustments when I play through the PA.

My monitor is not pretending to be FRFR - it's a wedge desined to be a general stage monitor. Sounds great though and I thought would be a similar sound to FOH through the PA.

At home I'm not using backing tracks. At the same time I was first at rehearsal so noticed this with nobody else there.  It just wasn't much louder when I turned up the guitar where as at home is massively different. 

We rehears in our drummers spare room with an electronic kit so while rehearsal is slightly louder than at home - it's not a  whole lot. 

I guess a real comparison would be to take the monitor to rehearsal - set that to be left out of of my Tonex - put the right into the PA - set them to be similar volumes then mute one at a time and see what difference the volume control makes for each. 

That would be very scientific way to approach it. Not sure I can be arsed to be honest thought Probably easier to just use 3 patches as I've always done.