Amps and room acoustics

bender · Post by **bender** » Sat Jul 19, 2014 7:51 am

I recently came to an unsettling realisation after hearing one of my amps in a different environment to its usual space. All of my amp buying and selling decisions since moving into the house I'm currently in have been informed/distorted by the acoustics of the space that the amps usually live in. I treated the space when it was renovated, but I left a few key things out that have had a really negative effect on how my amps sound down there... and I didn't realise how severe this was. It's been dawning on me for a while and last weekend I decided to put it to the test. I set up a mic, put my headphones on and played some chords, changing the position of the mic between strums. When I got to the corners of the room, the low frequency energy was so huge that it completely swamped the midrange detail and all I could hear was mud- pretty much the common reason for disliking all of the amps I've had since moving. Without headphones, this LF mud permeates the whole space, and it only gets worse with volume.

I'm going to investigate either building or buying some efficient bass traps to treat the corners with but the damage has been done unfortunately. I've sold two amps that sounded flat and uninspiring down there that sound incredible on all the recordings I made with them. Much regRhett!

The moral? Don't forget how much the space you play in affects your tone- it could be the main reason you don't like your sound.

Rog · Post by **Rog** » Sat Jul 19, 2014 9:41 am

Aa addendum to your experiences is this:

Whatever gear you have, you bought it because at the time, you liked what you saw/heard. If it now doesn't appeal to you - what's changed? I'm pretty damn sure the characteristics of gear doesn't change too dramatically by itself...

bender · Post by **bender** » Sat Jul 19, 2014 9:48 am

Rog wrote:Aa addendum to your experiences is this:

Whatever gear you have, you bought it because at the time, you liked what you saw/heard. If it now doesn't appeal to you - what's changed? I'm pretty damn sure the characteristics of gear doesn't change too dramatically by itself...

Absolutely. In both cases I tried the amps in a relatively dead sound studio and liked them, but low or lower-mid nodes in the rooms I've had them in subsequently have been pretty unforgiving. Recording with them has been fine, because I can mic them pretty close and get the true amp sound. Just practising or noodling and I hear things that I don't like- it just took me a while to realise that it was 100% the room, not the gear.

crowbgood1 · Post by **crowbgood1** » Sat Jul 19, 2014 5:17 pm

But I thought tone was in your fingers?

I had this friend and he had this high roof warehouse with all his gear. Everything you played through sounded so good!!! Would have been a great place for a music shop

willow13 · Post by **willow13** » Sat Jul 19, 2014 5:24 pm

crowbgood1 wrote:But I thought tone was in your fingers?

I don't know man with the chill in the air this morning my fingers were stiff and hurt when touching the strings but my tone was the same as usual

hamo · Post by **hamo** » Sat Jul 19, 2014 8:04 pm

willow13 wrote:
crowbgood1 wrote:But I thought tone was in your fingers?

I don't know man with the chill in the air this morning my fingers were stiff and hurt when touching the strings but my tone was the same as usual

I had to take my hat off to the busker playing steel string acoustic outside the railway station the other day in freezing conditions. Metaphorically take my hat off of course - too cold to really lift the beanie!

crowbgood1 · Post by **crowbgood1** » Sun Jul 20, 2014 12:34 am

I remember reading an artical somewhere "treat your room for under $150" or something like that. They used 4" by 4" screwed onto plywood base's, so they would stand up, wrapped them in a couple layers of carpet and stood one up in each corner.

I'll be interested to see what you use Ben to tame your low end problems.

I can see the domestic negotiations already.... "Man! we need to sort out the studio's bass issues, it's costing us thousands"!

druz15 · Post by **druz15** » Sun Jul 20, 2014 1:54 am

The number of people who bring shit back to the store the next day because "it sounded good in the shop but when I got it home, nah"
well that's not my fault, your home/amp/wiring is to blame

bender · Post by **bender** » Sun Jul 20, 2014 7:36 am

crowbgood1 wrote:I remember reading an artical somewhere "treat your room for under $150" or something like that. They used 4" by 4" screwed onto plywood base's, so they would stand up, wrapped them in a couple layers of carpet and stood one up in each corner.

I'll be interested to see what you use Ben to tame your low end problems.

I can see the domestic negotiations already.... "Man! we need to sort out the studio's bass issues, it's costing us thousands"!

First step is to try to make do with what i have. I've got a 1200 square piece of sound treatment left over that I'm going to cut in half and wedge across the two front corners. If that has any effect, I'll build frames for them and mount them properly and will buy another sheet so they can cover the full height of the room. I suspect that I also might need to do the corners between the ceiling and walls, but that'll be a bitch to sort out.

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bender · Post by **bender** » Sun Jul 20, 2014 7:49 am

druz15 wrote:The number of people who bring shit back to the store the next day because "it sounded good in the shop but when I got it home, nah"
well that's not my fault, your home/amp/wiring is to blame

Yep. Acoustics can be subtle too. All the tests I've done in my space show that it's pretty dead... until you get down below 100Hz. It sounds really neutral until you play something bass heavy (like my Ampeg) and loud. At first, everything just sounds loud, but on closer inspection...

Just to confuse matters, I've done a fair bit of guitar recording with the mic waaaaay back from the cab and it sounded great.

Gonzbull · Post by **Gonzbull** » Tue Aug 19, 2014 6:46 pm

I totally feel your pain. Treatment is so important. You can never go wrong with bass trapping.
Also diffusion can work wonders alongside absorption. I have my studio dead at the front and slightly live at the back.
Raising amps of the floor and away from back walls helps too. I always move amps around to find where they sound best and record them there.

Anvil Amps Alan · Post by **Anvil Amps Alan** » Wed Aug 20, 2014 7:02 am

Boundary effect.
Speaker placed directly against a wall (Facing out) = +3dBa (twice as loud)
Placed backed into a corner = +6dBa
This applies to low frequencies especially.
Reflections and absorption cause peaks and dips at different frequencies and will also change with every room.

Post by **Slowy** » Wed Aug 20, 2014 8:42 am

Just a thought Ben, forgive me if it's an idiotic question. I remember you keep your amps on the floor. Do you leave them there when you're recording them? Getting them off the floor onto a chair can make quite a difference.

bender · Post by **bender** » Wed Aug 20, 2014 9:08 am

slowfingers wrote:Just a thought Ben, forgive me if it's an idiotic question. I remember you keep your amps on the floor. Do you leave them there when you're recording them? Getting them off the floor onto a chair can make quite a difference.

I don't actually keep them on the floor. They're always elevated about 6inches and about the same away from the wall. I've tried raising them higher but it doesn't make any difference to this particular issue.

The issue I'm talking about is actually quite a subtle one and is independent of amp position. What it is is a build up of low frequency energy in the corners of the room. It's barely noticeable, but it adds a bit of murk that has the effect of making it seem louder than it actually is. Recording isn't a problem at all, because I mic relatively close. What made it stand out for me was that turning the amp down past a certain point makes it disappear, which gives the impression of a large volume drop at a certain point on the dial (which doesn't actually exist at all). The issue is nothing like as bad when using a 10" speaker. Every amp I've played that has a 12" speaker has seemed to have a subtle wooliness to it.

All I was really getting at in the initial post is that I need to fix my room (a bass trap in each corner starting with the console end of the room is the plan) before I make any critical amp decisions.

bender · Post by **bender** » Wed Aug 20, 2014 9:11 am

Anvil Amps Alan wrote:Boundary effect.
Speaker placed directly against a wall (Facing out) = +3dBa (twice as loud)
Placed backed into a corner = +6dBa
This applies to low frequencies especially.
Reflections and absorption cause peaks and dips at different frequencies and will also change with every room.

Yep. The area where the amps are placed is treated and is actually fine. I just have a natural LF buildup in the corners of the room. You can move a mic around the room and hear it surge as the mic approaches the corners.

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