Small room studio

[spottydog1001]

We moved a few months ago and found a nice quiet place with a brick outbuilding,
Had a new floor put in then put LOTS of fluffy Nauf in the ceiling and behind a new stud wall for sound proofing purposes, then plastered, new skirting and painted.
I made 3 floor to ceiling corner traps with 100mm RW3 and already had a few pro made standard size ones, and ordered some Iso Bond panels for above the listening spot. It's a lot of treatment but the room is small and I knew it would sound like working in a box after the plasterboard.
It's all wired and and working, sounds pretty good and the REW figures aren't bad at all but there is a spike at 150hz I'd like to improve if anyone can suggest anything?
Thanks.
https://drive.google.com/file/d/1GibKbe ... sp=sharing

[Drew Stephenson]

If it's a specific frequency you're trying to target it may be worth getting in touch with someone like GiK acoustics, they do some tuned traps for that purpose.

[Music Wolf]

What are the dimensions of your room?

[Wonks]

I think you've linked to a data file, so I can't see anything. Is it an upwards (boost) or downwards (dip) spike? If upwards, you could try a simple reverse EQ cut on your speaker bus, or for something a bit more complex, the Sonarworks room EQ package?

I'm just thinking that in a small room, you might not have the space for a trap big enough to tame a 150Hz spike, or have the money for an active bass trap, so try software to level out what's left.

[Music Wolf]

[spottydog1001]

Thanks for the graph screenshot wolf.
Measurements of the room after the plaster boarding is:
L 17 ft, W 8ft, H 6Ft 6 inches.
I agree with the 150hz probably needing more treatment than I can muster in the room wonks, if there was a quick adjustment I'd be up for it. REF4 seems to level it out pretty well.

[Drew Stephenson]

Dips are harder to correct with software than peaks, because you're fundamentally just pushing more power into a null that will still be a null because of the physics of the room.
You run the risk of using up all the headroom in your amp trying to fill in something for minimal return. I'd be looking for a physical solution first.

[spottydog1001]

Hi Drew, any suggestions to improve the dips?

[Wonks]

As Drew said, it's almost impossible to counter dips in software as the room nodes just cancel a louder signal.

I don't know if it's ever been done before, or how good a suggestion this is, but it seems that you might be able to pull down the peaks by a few dB to create a fairly flat plateau, leaving the dips untouched, but then having an overall frequency response that you could call flat to say +/- 3dB. Your monitor amps would have to work a bit harder, but you should still have sufficient headroom with decent monitors.

Otherwise tuned bass traps, as has been mentioned above, or, if you're got £3k or so going spare, an active bass trap. E.g. https://www.soundonsound.com/reviews/ps ... -avaa-c214

[Sam Spoons]

If there is a dip at 150Hz at the listening position caused by room modes surely there will be a corresponding peak at 150Hz elsewhere in the room? The job then would be to reduce this peak with a tuned trap.

I assume you measured at the listening position and given the depth of the dip I'd guess that it is close to the centre of the room? The wavelength of 150Hz is about 7' 6", do you know if 150Hz is the exact frequency (it's hard to interpolate from the logorithmic scale on the graph)? Have you measured the FR of the room in different positions? It may be that sitting in a different place and/or moving the monitors could improve things.

[spottydog1001]

Exact figures for the bumps are 62.6 and 158.5.

The way the room is set up at the moment facing the long wall is the most convenient for me, everything fits and is easy to hand. It's a room purely for myself for song writing but I'd like the best mixes possible when I send the work off - more for pride than anything else.

I made 3 floor to ceiling corner traps with 100mm RW3 and already had a few pro made standard size ones, and ordered some Iso Bond panels for above the listening spot. It's a lot of treatment but the room is small and I knew it would sound like working in a box after the plasterboard. There's a bunch of guitars to go in also.

[img]https://drive.google.com/file/d/1dP8jUS ... sp=sharing[/img]

[Hugh Robjohns]

It's very easy to get fooled by measurement plots.

What does the room actually sound like if you play a bass step tone sequence?

Does it sound as grossly uneven as that plot suggests?

Big nulls can only be solved by better bass trapping. It exists because the sound from the speaker is being reflected, and that reflection is cancelling the direct sound. Kill the reflection and there's nothing to cancel, so no deep dip.

Given the frequency, I'd be looking at the side walls as possible culprits, but moving the speakers might well help, too.

[Sam Spoons]

I'm guessing you are exactly halfway along the long wall then? And in your mix position almost exactly halfway across the width? If so then that is probably the worst position you could be.

Have you measured the FR at different places? Maybe moving the desk and monitors a couple of feet towards on end of the room would improve things (I think it would compromise stereo imaging but probably not much given the distance the speakers are from the 'side' walls). Or, is there any way you can set the room up so your speakers are firing along the room?

[spottydog1001]

Hugh, I have played a bit of bass in there, it doesn't sound madly out but not perfect either, I'll test again tomorrow, I'd imagine the bass issue is thew back wall but could be wrong.

Sam, I'm pretty sure the way I've set up is going to be permanent but I will retest with the desk pointing down the long wall just to see. If it's wildly better I'd have to rethink.

Thanks chaps.

[Sam Spoons]

It's always worth experimenting if you can. Convenience sometimes trumps (lower case 't') acoustics but only to a point. You could almost certainly improve the sound significantly by putting the desk against a short wall and adding a four foot deep, wall sized, bass trap at the opposite end but usually a door or something gets in the way or the size of the room means you can't afford the space.

[spottydog1001]

Sam, had a look today re moving the desk facing the short wall and it's not really feasible.
Both objections hold true - door on the back wall right by a corner and not enough space to be comfortable in.
The £2000 bass traps are too expensive so I'm just going to live with what I have. It sounds pretty good in the room so I'll do a couple of mixes and see how they translate and take it from there.

[Sam Spoons]

Have you tried measuring the FR at different places in the room? If you can move your listening position away from the mid point you should find the deep null is significantly reduced.

[Martin Walker]

Have you tried measuring the FR at different places in the room? If you can move your listening position away from the mid point you should find the deep null is significantly reduced.

Yep, I just noticed that no-one has yet mentioned the oft-recommended '38% rule', whereby you can often get a 'flatter' sweet spot playback response in a room by placing your listening position 38% from the front wall, to minimise the effects of room modes.

It's certainly a good starting point, and has worked well for me!

Martin

[Sam Spoons]

Yes, in the case of the OPs room and mix position he is facing a long wall and, I'm guessing, positioned in the middle of the long dimension (17 feet). With the nominal front and back walls being only 8 feet apart that would place him 3' from the back wall and 5' from the front. But the main issue I suspect, is the long dimension and moving the rig sideways to a point closer to 6' 6" from one end of the room should mitigate any modes between the end walls. As I said above this may compromise stereo imaging but it's worth a try.

[spottydog1001]

I moved the desk to the 6ft 6 from the left wall listening position as suggested and took a measurement.
I cant see a great deal of difference but this is the first time I've measured a room with REW so I don't really know what I'm looking at:)

[img]https://drive.google.com/file/d/1Lt7qo7 ... sp=sharing[/img]

[Watchmaker]

I hear a lot about needing depth for bass trapping. My research has turned up one avenue I'll be exploring once my shop gets warmer than -8C.

That avenue is to build a combination trap - essentially a perforated panel in front of a free hanging limp mass in front of a 2" piece of Owen Corning 703* all housed in a rigid box. I have a fairly high degree of carpentry and experience building broadband absorbers so the build will be easy for me.

I have no personal experience with this yet, but my calculations lead me to believe I can build a trap tuned to 68 Hz with .98 coefficient in a box about 4" deep in a 3' x 6' frame. I'm not decided on what insulation to use I'm still coming to grips with the physics of flow resistivity in this and I haven't determined how many Sabins it'll contribute...However, faced with similar constraints to yours, I have nothing to lose by trying!

Check out:

http://www.acousticmodelling.com/helmholtz.php
https://www.acousticsciences.com/artblo ... ass-traps/

[Sam Spoons]

Hugh built some limp mass bass traps for his studio and discussed the build here https://www.soundonsound.com/techniques ... sound-good

[Music Wolf]

Hugh built some limp mass bass traps for his studio and discussed the build here https://www.soundonsound.com/techniques ... sound-good

I've just (as in last night) empoyed this technique in my own studio make-over.

https://www.soundonsound.com/forum/view ... 37#p952837

Initial results are promising.