Room treatment

[realysm42]

I searched for the other thread to no avail, so mods please add this to it if you know the one I'm talking about :D

I've recently moved to a new flat and the listening room (aka living room) has some a good point:

It allows my sytem to breathe more as I've actually got some space to put my hi-fi and give some reasonable space between the speakers (pictures to follow).

The issue:

I'm now faced with a particular frequency that sounds disproportionately louder than the rest (it's a mid bass one as it comes from the bookshelves, not the sub) and the whole place is a bit 'shouty'.

I've taken the plunge and bought two broadband acoustic panels (http://www.studiospares.com/acoustic-panels/braodway-broadband-x1-beige/invt/464260/)and three bass traps (http://www.studiospares.com/bass-traps/universal-acoustics-jupiter-bass-trap-600mm-grey/invt/466010/). I know this is highly subjective but how do you guys have your treatments fitted and did you have a mess about to try and work out the optimum performance? How did you experiment with the positioning, given that it can be pretty destructive mounting and moving things until the optimum positions are found? Any advice/comments are more than welcome.

I'm going to use these (http://www.3mselect.co.uk/p-544-command-picture-mirror-hanging-strips-medium-1kg-for-hanging-pictures.aspx) to mount the bass traps (they're more that strong enough).

(I'm guessing I can't really go wrong (within reason) as pretty much all of the walls are just painted concrete, lots of lovely reflective/hard surfaces :doh:).

I spoke to the guy on the website and he said it's best to buy a small amount and just build it up as you don't want to over do it.

Speaking of the devil it's just been delivered so I'll report back later with my (initial) findings :eyebrows:

[MartinT]

My TubeTraps naturally go in the corners of the room and the only adjustment they need is to spin them for the best absorption/diffraction. I have mine set for maximum absorption. The PicturePanels help dampen the wall facing me and the one behind me, and a new ArtPanel covers the large glass area of the TV. Finally, my SubTrap (without a subwoofer) is set to the left of me as that is where I heard the worst of the upper-bass boom when the room was empty.

[Sonority]

If correctly made then you cannot 'overdo' bass traps.
It is reasonably easy to 'overdo' full range traps - but just as easy to correct.

I suspect the bass traps are actually full range and thicker than the broadband?

Bass tends to build in the corners of a room (there are 12 corners to a box remember) but you will probably find your rear corners to be the best place to start for bass traps. This could end up being your front corners - only experimentation will show that.

IMO broadband in a room should start at the first reflection points.

Your speakers are not 'producing' the pronounced bass you are hearing - it will be a function of the room measurements and a doubling of a certain frequency - ie, a mode.

Have fun with the treatment - it's well worth the effort.

[Clive]

As already mentioned first reflection points are your first port of call. A mirror is your best friend for helping you locate the correct positioning, I had shouty issues such as described in the OP. I have a very live room with only partial carpeting, also OB speakers. I have panels at first reflection points in front of the speakers and some behind too (due to the OBs), plus one central panel on the wall behind the speakers. I also have foam scattered on the uncarpeted areas of floor in front of the speakers (which I pick up when I want the room to look less untidy).

[realysm42]

Thenks for all the tips gents, I'll take them into consideration whilst experimenting.

Clive, like the sig! :eyebrows:

[Clive]

Clive, like the sig! :eyebrows:
I saw yours, mine was so nearly same but without the blue which I rather liked so I copied your blue, I hope you don't mind!:cool:

[realysm42]

Of course not mate; it makes it a lot quicker and easier to read. It actually saves having to ask people/remember what they've got as a point of reference.

[MartinT]

It actually saves having to ask people/remember what they've got as a point of reference.

That's why we like equipment lists in sigs ;)

[realysm42]

Yeah makes sense!

Okay so I got the broadband ones up; one right behind the listening position and the other catching the first opint of reflection of the left speaker (the right one's not by a wall). They make a nice difference, everything seems a little less forced/loud, slightly more natural, I think I'm happy yo leave them at the amoung I have as I know it can be over done.

I put the bass traps in a few different places and that f*cking bass frequency didn't flinch. Infact the bass sounded no different atall. I could have the listening room from hell I'm not sure, it looks like this:

http://i135.photobucket.com/albums/q153/realysm42/Untitled-16.jpg

What do you reckon chaps?

[MartinT]

Martin - play some music that excites that bass resonance and walk around the room listening. Find a spot in the room where the effect is particularly pronounced - it may not be where you expect. When you find it, put a bass trap there. Repeat a couple of times. Now listen again from your listening seat. Any better?

[StanleyB]

If all else fails, get an equalizer..

[Si74]

If at all possible, I'd move the speakers to the left hand wall with the sofa facing them.
As it stands you will face a huge problem balance wise with that great space
on your right.
I'd very much doubt the bass traps behind your couch? are doing much, try moving one to each of the first reflection points.. but in that room:(

[bobbasrah]

Not sure that moving bass traps to the FRPs will do a lot for bass attenuation.... Bass build up will certainly be in corners, and the settee will create a further bass resonant void as it is so close to the wall. You will notice it when you lean back on the settee.

A drape/carpet/lightweight panel will do well at FRP, leaving the broadband panels for use elsewhere like back corners or arranged directly behind listening position above the settee.
Would a movable panel (think office divider) or bookcase be possible on the right FRP to bring back partial symmetry?

Awkward room shape otherwise. The kitchen area will be a problem with respect to modes, and reflections from the RHS speaker will create a muddle.

Martin's (MartinT) suggestion is good in terms of moderating the modes.

I have a similar concrete box but without the dog leg kitchen, only my LHS is a partition door so can be left open - No FRP, but symmetry.

[realysm42]

Thanks all for your suggestions; I'll bare all of it in mind and have another go tonight.

If it's a fight that frequency wants, it's got one.

Stan, an eq would be cool, but I can't afford to buy another set of xlrs of the same calibre I've got and won't settle for anything less!

***Edit*** Bob, I've experienced what you've described already; I sat on the floor to show my gf the issue and could barely hear it, when I sat back on the chair, there it was again...

[Sonority]

I hate to say it but to make a big dent in low frequency with traps takes a fair few more traps than you have to play with at present.

My*personal* vote, if you want to get rid of a serious mode would be a) identify said mode and b) then go with a tuned trap akin to what Martin has - then start with the general bass issues that we all suffer with.
Please don't take that the wrong way - but low bass is a big monster to get rid of and you simply will not do it with a few bass traps :(

[Clive]

A few tube traps plus a DSP unit (eg Behringer) in front of the subwoofer may work. I don't know how low the main speakers go. If the subwoofer is doing most of the bass and it's connected at line level then DSP is a good option. It works really well for me in what is almost a square room

[realysm42]

I hate to say it but to make a big dent in low frequency with traps takes a fair few more traps than you have to play with at present.

My*personal* vote, if you want to get rid of a serious mode would be a) identify said mode and b) then go with a tuned trap akin to what Martin has - then start with the general bass issues that we all suffer with.
Please don't take that the wrong way - but low bass is a big monster to get rid of and you simply will not do it with a few bass traps :(

I don't take it the wrong way at all, it's helpful information, so thanks!

I had a walk round whils playing a song that excites said frequency, I've placed the traps where it was worst, oddly enough it's in the area I sit in so up they've gone.

It's made a small difference tbh and goes hand in hand with what you've said here. I had a look at J River's EQ for a laugh and started with the lower frequencies; by the end of it, I'd put everything down to minimum across the whole spectrum ( 60HZ to 16KHZ, so in the end everything in said range was down 12db and still it persisted) and all I was left with was that bloody frequency?!

My sub isn't even switched on right now, I've no need for it and the (11 litre) loudspeakers I've got produce far too much, loud bass! They're meant to cut off at 39hz (in room).

Does this mean the EQ doesn't reach low enough to make a difference? I'm guessing yes.

That stumped me a bit, the EQ ranges from.

A tuned bass trap sounds like a good idea, how can I work out just where my enemy lives please?

[realysm42]

Just stuck Windows Media Player on, it's got an EQ that reaches down to 31HZ, sliding this down to nothing removes the issue entirely, confusingly enough, sliding the 62HZ down also affects the bass issue too, so I'm thinking the problem lives somewhere in that range, if that helps inform anyone's replies.

[Stratmangler]

This is useful to give you an idea of the frequencies of various notes.
Bottom E on a bass guitar is around 41Hz, so you can work your way up the scale from there.
http://www.seventhstring.com/resources/notefrequencies.html

[Sonority]

Just stuck Windows Media Player on, it's got an EQ that reaches down to 31HZ, sliding this down to nothing removes the issue entirely, confusingly enough, sliding the 62HZ down also affects the bass issue too, so I'm thinking the problem lives somewhere in that range, if that helps inform anyone's replies.

If a rooms major mode is at 30Hz, it is also going to have issues at 60hz & 120hz to lesser degrees, hence your 62hz also affecting your issue.
Fun isn't it :)
It's all about achieving a reasonable balance in your room, or as close as you can.
I have one left to do in my room - but that will take a back wall nearly 6' thick in rockwool, or a dedicated 31Hz trap (which is now available - oddly) and would just fit in with what space I have left.
I have yet to go there as it is, in all honesty, a small issue to me.
(GIK Acoustics Scopus tuned trap is what I'm considering)
The only way you are going to find your rooms major modes is physically measuring it.
That said - you are progressing - depends how far you want to push the envelope.
You will find - the more you do the better it gets, especially with the 'bass' issue.

[bobbasrah]

It is always going to be a compromise Martin, it is a living space with kitchen/dining attached after all, not a dedicated listening room. With the odd room shape, you would do well to consider how you can create a pseudo-symmetrical listening environment before dwelling on room-modes IMHO.

The points Stephen made are valid both on the limited number of panels you envisage and the issue of harmonics.
In these cases predominant attention is on the fundamental resonance (mode/bass trapping) before looking at the harmonics which broadband panels can and do moderate.
Remember that modes and harmonics are amplification of the room, notably in room corners and in your/my case behind the seating.
I stuck up broadband panels in all four corners, and behind and above the settee, which created a balanced environment.
Do the modes still exist? Yes but at low level. Are they intrusive? Not until I really crank it up.

[realysm42]

Thanks gents, really helpful information.

Stephen, where are you getting your 31hz bass trap from please?

Also, how does one go about measuring ones room please? I'm going to return the bass traps and take your advice on egtting a bespoke one.

[Sonority]

Thanks gents, really helpful information.

Stephen, where are you getting your 31hz bass trap from please?

Also, how does one go about measuring ones room please? I'm going to return the bass traps and take your advice on egtting a bespoke one.

''I have one left to do in my room - but that will take a back wall nearly 6' thick in rockwool, or a dedicated 31Hz trap (which is now available - oddly) and would just fit in with what space I have left.
I have yet to go there as it is, in all honesty, a small issue to me.
(GIK Acoustics Scopus tuned trap is what I'm considering)''

Please google Ethan Winer Music Player Forums and have a look at his acoustics forum. In the FAQ there you will find more stuff than you can possibly imagine. Measuring a room can be from reasonably easy to mega expensive (ring any hifi bells) but be aware that moving the measuring mike just 1" can give wildly differering results to someone who has no idea what he is looking at :-

http://i12.photobucket.com/albums/a221/sph2701/Hi%20Fi/sh-wfall.jpg

Whether you go down the road of buying a cheap mike and using the listed software or getting someone in to measure your room is a decision to be made, or do you just keep going as you are now..
Cheers.