Weird tone at rehearsal/stage volume.

[Jorn218]

I have noticed something with my amp that I would like some advice on how to killl, or I'll just have to deal with.

This concerns the red channel on my 3ch dual.

Settings are as thus(so we are on the same sheet of music):

Presence: 10:00
Master: 1:00
Gain: 11:30(gain pot is 1M)
Bass and Treble: 1:00
Mids: 11:00
red channel modern
Bold and diodes

When I turn up to rehearsal volume about 9:30-10:00(Output) depending on the day, I am getting a mid bump, that kills an otherwise fairly decent tone. I am turning up just enough to hear myself over the drums(also so my second guitarist can just hear me as he is set up on the other side of the drum set). When I was a Marshall player, this tone was when the power tubes started into power tube clipping. Am I getting the same thing in this instance? could this improve(read get rid of) by turning the Master down and the Output up to compensate? Or is this just a tube amp being a tube amp.

I am asking because I was under the impression that Rectifiers were designed to have a relatively clean power section, letting the preamp do most of the work.

 

[jdurso]

By mid bump are you saying the tone is losing its dynamics and sounds boomy/over compressed? Without knowing more it sounds like the amp is at max compression... Try backing off the channel volume and bumping up the output to the level you want/need. If that doesn't help I'd look into a possible tube replacement.

 

[screamingdaisy]

I am asking because I was under the impression that Rectifiers were designed to have a relatively clean power section, letting the preamp do most of the work.

IMO, that is a belief commonly held by people that've never turned up a Rectifier. Yes, the distortion is primarily preamp when compared to something like an old Marshall, but the power section definitely influences the final tone.

Some of what you're getting is also the tone shift in the speakers as they start getting pushed harder.

If you've EQ'd the amp for low volume/bedroom sound you'll probably need to re-EQ it for band use.

 

[screamingdaisy]

Also, try backing the red channel master off to 10:00 and increasing the master output to compensate.

 

[Jorn218]

@jdurso losing a little bit of dynamics, tubes are less than year old , but with new production tubes, they may need replacing.

@screaming daisy, amps eq was set at volume. Think you are on to something with the eq shifting due to speakers being pushed.. Ill change the master/output settings to see if this makes difference.

I just noticed this within the last week. But i am also standing closer to my amp at rehearsal than few weeks ago which is when I noticed this. Moving several feet away from the amp lessons the effect considerably. I am now thinking I am hearing a type of proximity effect, as the mid bump is lessoned moving away from the amp.

For a generalization of what I am perceiving is somewhat akin to a wah pedal set in the sweet spot and left on. But like I said, this pretty much goes away once my ears are further away from the amp.

 

[screamingdaisy]

Adjusting the volume/output levels isn't so much to change the sound as it is to reduce how much signal you're feeding into your FX loop. Somewhere between 9:30 and 10:00 seems to be the sweet spot on the red channel for producing power without overdriving the FX loop. Once that is set I adjust the other channel(s) to match.

Proximity effect makes sense. Recto cabs typically smooth out once you're about 20 feet in front of them and get better as you move away. I'm used to hearing my cab from about 7-10 feet out and am always kind of surprised at how good things sound when I get to stand further out.

Additionally, the sound will change when you change rooms. Some are uncontrollably boomy... others will produce all midrange. Sometimes shoving the cab a few feet to the left/right will add fullness or thin out the sound.

 

[Blaklynx]

I just noticed this within the last week. But i am also standing closer to my amp at rehearsal than few weeks ago which is when I noticed this. Moving several feet away from the amp lessons the effect considerably. I am now thinking I am hearing a type of proximity effect, as the mid bump is lessoned moving away from the amp.

Spot on.

It's the frequencie's wave length. Another way to look at it:

Consider HiFi speakers with a seperate sub woofer; if all speakers were next to each other and you stood close to them, the sub would sound weak, the mids and highs would be strong. Walk back 4~5m and the sub would sound strong. Walk back 20m the sub would still sound strong but the mids and highs would suffer (less volume).

Low frequencies have a lot of energy so travel further. High frequencies have less energy so travel the shortest and mids fall inbetween.

Low frequencies also have a long wavelength compared to mids, and highs have very short wavelengths. By the time the low fequency wavelength peaks (max volume), it may be a few metres from the speaker, whereas mids and highs have peaked (max volume) several times in that same distance.

It's hard to explain in words. Best if you draw 3 lines as sine waves on paper that represent low, mid and high frequencies. Draw the peaks of the waves the same height but draw the low as long wave, the high as short waves and the mids inbetween 9think of huge swells in an ocean versus ripples in a pond), but always start the three lines from the same point (which represent your speaker centre).

The height of the sine waves you draw at any given distance from the zero point (distance from the speaker) represents the volume of each frequency. You will soon see why the mids and highs sound strong versus the low end when a short distance away from the zero point.

The above is a very simple example to try and explain why things sound better when you're a few metres away from the speaker. We shouldn't forget about sound dispersion and reflections as well.

I think I explained things OK. If anyone wants to add or subtract, feel free (I could be wrong....)

By the way, at home my sub sounds weak until I get about ~4m away from it. When I'm in the correct position, it thumps and fills the overall sound of the HiFi speakers.