Bass issues (particularly amps) in home studio. Help!?

[jhill]

Hello all you slutty people. First-time participant, long-time voyeur. Thank you for all of your expertise/experience/criticisms/ideas/bad engineering jokes/etc...

So here's the deal. My band practices at a friends home studio. He has two small children and his wife is starting to get annoyed with non-sleeping/crying children. As is usually the issue, the bass amp is the main culprit.

He put a good deal of thought into his live room. If i had to guess I would say it is 25' x18'x8'. The walls and ceiling are two 1" QuietRock with an air gap..couldn't tell you more details at this point. Each doorway has two doors with mass loaded vinyl. I would guess that about 40% is covered with auralex foam, and the floor is carpet. It does sound pretty good, though it is dryer than I prefer...

I have started to notice some bass issues recently. There is definitely a peak area about mid room, which happens to be where I, the drummer, is set up. I'm thinking if i'm in a peak spot, then our bass player is probably in a null area. As I think this is part of the problem, I suspect that there is other issues at play, such as a complete lack of bass trapping.

I've done a bit of DIY (2" & 4" rockwool panels, QRD diffusers), and he wants me to help keep the peace in his house. I would like to keep the cost down as much as possible, so i'm doing some brainstorming. These are the ideas I have so far.

1. Corner wedge absorbers. They would use 2'x4' 2" (rockwool maybe?) on the front. I'm thinking either 4 or 6" deep. I would be doing 2 or 4 of these.
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I would likely build the cabinet out of plywood, completely sealed. What I like about this idea is that it would be space efficient, and they could double as small tables in the corners. Also to preserve higher frequencies, I could place 1/8" or 1/16" birch plywood on the front. It could be stained which would look really nice, but i have no idea where that would stop reflecting and start absorbing...

2. 2'x4' panels, either 4 or 6" deep. These would be mounted across the corners. This would be the easier build. Once again I would build 2 or 4 of these.

The main goal of this is to reduce bass from amps (apparently the kick isn't too much as far as I know). If I did the corner wedge traps, would placing amps right in front of them help? From my limited knowledge of acoustics, i'm thinking that placing the amps in front of these traps would eat up the bass radiating backwards. This would reduce corner build up, and lower the risk of phase issues from those waves traveling back out and messing with the perceived levels out front of the amps. Just a theory and I could be totally missing the point...

If anyone has input I would really appreciate it. Thanks! Have a good one!

[takman]

are you thinking that absorbing/trapping bass with room treatments is going to limit the noise problem outside the room? At least thats the impression im getting...although it seems that you also want to make the room sound better...

bass trapping is going to make the room sound better, and wont really have an impact on keeping sound from leaving the room and waking up sleeping babies...for that you need sound isolation...

[jhill]

Sorry, in trying to include as much information as possible, the post ended up somewhat convoluted...

Here's the main issue. Bass player can't hear himself during our practices. We actually practice relatively quietly, so I don't think volume is the issue. I'm thinking it has to do with phase and early reflection points...

Where I have been positioned during practice, the bass seems overpowering, but I (the drummer) am nearly in the middle of the room. Everyone else is around the perimeter, and they don't think it is particularly loud.

He plays an active bass that has quite a bit of tone, so it should be cutting through more. I've tried moving him around, tipping his amp up at him, rolling off the low end, moderate compression, and pretty gnarly hard knee compression. Nothing seems to make a big difference.

SO MY QUESTION IS...would placing the bass amp directly in front of a 6" corner bass trap help to clean up the sound in that spot enough that he can hear himself at a lower volume? Would one bass trap used strategically help in this specific situation? or are we looking at a more global issue of bass buildup in the room, requiring quite a bit more work.

I'm thinking in terms of intelligibility. You put a bass amp in a corner and it sounds louder, but sounds muddied. By minimizing the relections behind the amp, there should be less reflecting back out, which should improve intelligibility. With greater intelligibility, he should be able to keep his volume lower...

Is this feasible, or should I start thinking about making a bunch of 4" panels?

Sorry for the unclear post. I hope this is better. Thanks!

[takman]

placing the amp with the speaker firing towards or away from it? Either way, i dont think its going to work....

I think you should find a better position for yourself, then treat the room...being in the center for the drummer doesnt seem like a good place to me....

Theres not going to be anyway around this...you will have treat the room to a certain degree....since bass is the problem, start with bass traps....

lets see what the experts have to say anyways...

[jhill]

Yeah thats kinda what I was fearing, but I had to ask. Thanks for the reply.

Anyone else?

I should have titled this thread "Bass Intelligibility Issues"...

[takman]

hey bro....getting an answer from the knowledgable people here can be hit or miss at times..

if you dont get input form others here you can try these forums...

John Sayers' Recording Studio Design Forum • Index page

PRO RECORDING drums, guitar, bass, vocals, Pro Tools, Logic, Samplitude, Cubase, Ableton, Sonar, Reaper, Nuendo,

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good luck

[jhill]

Thanks takman for the websites. Good information!

I'm still really hoping one of you acoustic guru's happen upon this thread...

So once again to review (for anyone who's interested), we're having issues with bass volume & intelligibility in my band member's home studio. Bass player keeps turning up because he can't tell what he's playing, guitars player's wife gets upset that the kids can't sleep. The studio is a room inside a room, all walls & ceiling are 5/8" QuietRock/ 5/8" drywall/ 5/8" Quietrock Sandwiched (no air gap). The ceiling is attached to the floor joists. All vents are outside the room, and still lined with auralex. 2 doors on each doorway, each lined with mass-loaded vinyl. Room is about 25x20x7.5'. Carpet floors.

I have noticed some significant standing waves around 150-200Hz, though I didn't have a tone generator last time I was there. He has about 50% of the room covered with 2" auralex, and 8 total lenrd bass traps in the corners...(basically nothing)

QUESTION: Could moderate bass trapping (such as suggested below) decrease enough of the standing wave issues to help intelligibility, hopefully allowing him to play more quietly? How much bass trapping is usually needed for a room like this?

Here's a couple of my schemes...

Broadband Panel:
Rockboard 60 (705). Do floor to ceiling panels across 3 of the 4 corners (The door is in the 4th). They would be 1.5-2' wide, floor to ceiling (about 7.5ft) and 4" deep. They would be covered with fabric, and supported on the back via 1/8 masonite with wood framing. Could be made to be airtight.

Bass Trap:
Get some more QuietRock (the rest of the room is made of it). Use the same idea staddling the corners, only with the QuietRock installed into the corners, to make airtight triangle spaces. We could stuff some insulation behind them to prevent resonances. The question with this one is at what Hz the sound stops reflecting and starts to pass through...Any thoughts? I suppose it would QuietRock was used. Would this have a limited bandwidth like a Helmholtz? (my understanding is that a helmholtz always has an opening) Would stuffing it with insulation or mineral wool increase it's effective bandwidth?

Deflector/Bass Trap:
Make 1/4 Cylinder "deflectors" somewhat in the spirit shown on Ethan Winer's site. I know this isn't in the true random sense, but it would do something to preserve the high end. We would use thin 1/8th" masonite (bent 90 degrees over 2ft, radius is ~1.27ft) for the face, and make them airtight to the corners. Once again they would be stuffed with insulation (or line the back with rockwool) to prevent resonances. The question on this one is also at what Hz stops reflecting and starts passing into the cavity. Would using pegboard be a better option? Once again, would this operate in a limited bandwidth like a Helmholtz?

Lots of questions...I would greatly appreciate anyone willing to help. Thanks!

[RbShffr]

Originally Posted by jhill

QUESTION: Could moderate bass trapping (such as suggested below) decrease enough of the standing wave issues to help intelligibility, hopefully allowing him to play more quietly? How much bass trapping is usually needed for a room like this?

Basically, yes. I would probably stick to simple proven methods, but It would take quite a few panels in a decent sized room. 4"-6" 2'x4' panels of 703 or equivalent straddling corners with no hard back on them. Get some sort of membrane on the front of them (Frk, kraft paper, plastic wrap) Use vertical corners as well as wall to ceiling corners. I would start with 12 of these with the expectation that as much as 24 might be necessary. Check out the sticky on building bass traps in this forum for specifics.

First thing to try is getting the bass amp as well as the guitar amps and pa speakers physically off the floor (a bass re-enforcing boundary) on stands or chairs. Your problem could just as well be other instruments muddying up the room.

These things should help you hear everyone better and maybe turn down those amps, but to provide actual isolation from the rest of the house, beefing up the walls, ceilings, floors, and doors is the only way.

[jhill]

Cool. Thanks for the reply.

Stick to proven methods...got it! Brute force mass...