Severe bass null

[Ermz]

Hey,

There's been a long running problem that I've had in my space. Basically I've tried out 3 sets of monitors here, 3 sets of audio interfaces, and even feeding the monitors directly from an mp3 and CD player. Every time there is virtually no bass.

Now since I first discovered this many years ago, I've bought a whole new PC, I've switched my monitoring position around, I've bought monitor stands, and now I have the room acoustically treated with 19 panels filled with 75mm and 150mm thick rockwool.

The room dimensions are:

Length: 3.65m
Width: 3.42m
Height: 2.41m

I understand that these are extremely far from ideal, with the vertical and horizontal lengths almost making it a square. But could there be a bass null SO SEVERE that it seems to absolutely cancel almost all bass? My impression was that smaller rooms had more of a tendency to boom out rather than be a bass void.

Anyhow the mixing position is roughly 38% of the room's length and of course in the middle, width-ways. In front of me is a large glass window covering almost all of the front wall. To my rear there is a medium-sized wardrobe and a door leading to a bathroom. To the left is a wall separating my room from the hallway and to the right is a wall separating my room from the house next door. The walls are made of plaster.

I don't have any diagrams of the room layout, as I don't have any software to do them on. I can however provide some rough pictures if necessary.

If anyone could help out with some advice that would be helpful, thank you.

Cheers,
Ermin.

[Glenn Kuras]

I understand that these are extremely far from ideal, with the vertical and horizontal lengths almost making it a square. But could there be a bass null SO SEVERE that it seems to absolutely cancel almost all bass? My impression was that smaller rooms had more of a tendency to boom out rather than be a bass void.

You are going to have both nulls and peaks. The only way to really find out what is going on is to test the room and look at the graph. You can test the room with a program called Room EQ Wizard Home Page

Glenn

[Ermz]

Thanks Glenn.

Is there any particular calibration microphone/preamp I need to use this?

[Glenn Kuras]

Ethan Winer did some testing of different mikes here
RealTraps - Measuring Microphones

Might be worth doing a read.

Glenn

[Weasel9992]

Anything uncolored that has an omni pattern should do just fine.

Frank

[Ermz]

I'm thinking the standard RadioShack SPL meter should do the trick - it seems even enough in the lows.

My fear has always been that the lack of bass has been a room issue, and my tests so far have corroborated that fear. I suppose this is a last ditch effort to pray that some aspect of my gear is taking away low-end.

Given that I have 19 acoustic panels in here, and barely any room to move, there is absolutely nothing else I could do for the low-end in terms of treatment.

[Glenn Kuras]

Originally Posted by Ermz

I'm thinking the standard RadioShack SPL meter should do the trick - it seems even enough in the lows.

My fear has always been that the lack of bass has been a room issue, and my tests so far have corroborated that fear. I suppose this is a last ditch effort to pray that some aspect of my gear is taking away low-end.

Given that I have 19 acoustic panels in here, and barely any room to move, there is absolutely nothing else I could do for the low-end in terms of treatment.

Well you would be surprised on how your set up of he mix spot and how you have the panels placed can make a difference. Not to PUSH MY COMPANY, but one of the big advantages of buying the product pre made is you know it was constructed right and the company SHOULD give you personal service to work through the issues. But yes some rooms just suck.

Let us know how the tests come out.

[Ermz]

Oh believe me, if the shipping to Australia wasn't ridiculous, I would've ordered some GIK bass traps months ago.

We'll see how the testing goes. There is no doubt the panels in here have tightened things up a lot, but maybe the room is beyond redemption. Wait and see I guess.

[Glenn Kuras]

Originally Posted by Ermz

Oh believe me, if the shipping to Australia wasn't ridiculous, I would've ordered some GIK bass traps months ago.

We'll see how the testing goes. There is no doubt the panels in here have tightened things up a lot, but maybe the room is beyond redemption. Wait and see I guess.

No problem at all and totally understand. If you would like to post some pictures with more description of how they where built maybe we can help approve things.

Glenn

[johndykstra]

Is there no bass anywhere in your room? Meaning, if you stand in the corners or lay on the floor... still no bass?

[Ermz]

There is certainly a bit more, but nothing that I would consider a significant amount. Even in corners it pales in comparison to the amount of bass I hear in local pro audio stores auditioning rooms and my friends' rooms.

As far as pictures, I've got a few, but you have to keep in mind that this is a rental property, so I've done what I could with making them free standing. The sides are parallel, but the rear, due to functionality reasons, is not.







I've essentially tried to straddle every free corner without destroying the accessibility of the room.

The bass traps, of which there is 7, are 150mm thick (6 inch, give or take) and the broadbands, of which there are 12, are 75mm (3 inch, give or take).

The insulation material used was Bradford Soundscreen, which is apparently only 32kg/m3 (found that one out a bit too late).

The next run of panels I will be doing with my friend will likely be Tontine Acoustisorb 3, which is 48kg/m3.

[Glenn Kuras]

I think at this point it would be best to test the room and lets see some graphs. I will say you do need something on the back wall.

Glenn

[Weasel9992]

I was just commenting on this idea on another thread: sometimes some very unorthodox trap placement can make a big difference in hammering down those tough nulls. Shoot the space with all the traps in the usual places for sure, but don't be afraid to put 'em in odd places as well.

If you can't treat the ceiling or the back wall, that may pose a problem in dealing with that null, especially if one dimension is double the other.

Frank

[Ermz]

Is there anything in particular you think I need to do to the back wall?

I can in all honesty say that I've crammed in as many of these panels as is even remotely practical. It's actually kind of hard to move around in here as a result. The back wall in particular contains 3 of the 150mm bass traps and 5 broadbands. I can't imagine what else I could do with it.

[Glenn Kuras]

Originally Posted by Ermz

Is there anything in particular you think I need to do to the back wall?

I can in all honesty say that I've crammed in as many of these panels as is even remotely practical. It's actually kind of hard to move around in here as a result. The back wall in particular contains 3 of the 150mm bass traps and 5 broadbands. I can't imagine what else I could do with it.

I would try moving those side panels in the back side walls to the back wall. Most of the time we commend 6" panels back there, but you can try those to see if things change at all.

Glenn

[DanDan]

Hi Ernz, that's a tough one. Your room is effectively square as far as bass is concerned. I have dealt with a few of these situations and I think I can help a little here.

Quick fix
You are at the 38% spot. This is a well established rule of thumb but the exceptions make the rule. You are in an exception. The centre of almost any room has the least bass, a square multiplies this effect. There is no way out of that one. I suggest you move everything towards the front wall. Have your speakers almost touching the wall. Then reposition your mix seat to include yourself in an isoceles triangle with the speakers. If you have too much bass here, which I doubt, back the speakers out a little. You might be able to leave the bathroom door open, with a heavy curtain perhaps. If the reverb is not too audible at mix this little trick can make quite a difference.

Big fix
You have Bass Traps straddling some corners. In the picture they seem to be only half the room height. You need to double them. I would also fill the space behind them with Fibreglass. The attic stuff would be OK, leave it in the plastic wrapping. Again full height. Alternatively, if you are up to some more DIY, construct 34 inch wide SuperChunks (studiotips - tips on studio design, acoustics, and wiring) in all corners. These are very very powerful and take up a little less space than straddling. Ditto GIK TriTraps. You could then hang your existing panel traps in the ceiling/wall corners. Sorry to repeat but again trap ALL of them. There is no possibility that you could overdo this. If you have space at any of the floor/wall corners- more Bass Traps. If you go to all this effort you will definitely be rewarded with a significant improvement throughout the whole room. More and firmer Bass, that varies less from note to note. You will still need to optimise your mix and speaker positions. Software is great for finding those optimum positions.
Room Analysis Primer

Good Luck with it, DD

[Ermz]

Thank you Glenn and DanDan.

Given that this is a rental property I don't have many options in regards to straddling the ceiling/wall corners, so I think I'll try the mix position shift you suggested and work it from there.

Superchunks would be a possibility if I didn't have my electrical power outlets right in the corners of the room. The room itself could hardly be less ideal for audio work. Otherwise I would love to do Superchunks and would do so without hesitation.

I should also mention again that the 'wall' in front of me consists of one large window, so it's hardly a wall per-se. Should that not minimize the 'square' effect of the room, given than the drapes and glass wouldn't be reflecting lower frequencies back?

[Glenn Kuras]

Originally Posted by DanDan

Hi Ernz, that's a tough one. Your room is effectively square as far as bass is concerned. I have dealt with a few of these situations and I think I can help a little here.

Quick fix
You are at the 38% spot. This is a well established rule of thumb but the exceptions make the rule. You are in an exception. The centre of almost any room has the least bass, a square multiplies this effect. There is no way out of that one. I suggest you move everything towards the front wall. Have your speakers almost touching the wall. Then reposition your mix seat to include yourself in an isoceles triangle with the speakers. If you have too much bass here, which I doubt, back the speakers out a little. You might be able to leave the bathroom door open, with a heavy curtain perhaps. If the reverb is not too audible at mix this little trick can make quite a difference.

Big fix
You have Bass Traps straddling some corners. In the picture they seem to be only half the room height. You need to double them. I would also fill the space behind them with Fibreglass. The attic stuff would be OK, leave it in the plastic wrapping. Again full height. Alternatively, if you are up to some more DIY, construct 34 inch wide SuperChunks (studiotips - tips on studio design, acoustics, and wiring) in all corners. These are very very powerful and take up a little less space than straddling. Ditto GIK TriTraps. You could then hang your existing panel traps in the ceiling/wall corners. Sorry to repeat but again trap ALL of them. There is no possibility that you could overdo this. If you have space at any of the floor/wall corners- more Bass Traps. If you go to all this effort you will definitely be rewarded with a significant improvement throughout the whole room. More and firmer Bass, that varies less from note to note. You will still need to optimise your mix and speaker positions. Software is great for finding those optimum positions.
Room Analysis Primer

Good Luck with it, DD

Like always DanDan great advice. It looks like I may be traveling back and forth between the UK and here so maybe I could pop over for a pint some time. Rumor has it you guys have GREAT TASTING BEER?

[Glenn Kuras]

I should also mention again that the 'wall' in front of me consists of one large window, so it's hardly a wall per-se. Should that not minimize the 'square' effect of the room, given than the drapes and glass wouldn't be reflecting lower frequencies back?

some what, but don't count it out.

Glenn

[Weasel9992]

Sometimes it takes breaking some rules to get the room to sound right. Take the 38% point, for example...it's a starting place. Move around until you get the best response. Move panels around until you get the best response. It can take a while to get everything where it needs to be, but keep experimenting.

Frank