Room acoustics

[Clive]

I've recently changed my listening room around, it took me a while to get the bass right when I did this, I'd be interested in views on the effectiveness of putting some extra effort in.

The speakers are Bastanis Altas, these are open baffle; 2 x 12 inch widebands + 1 tweeter per channel and 2 solidstate subwoofers operating up to 80Hz / 100Hz.

My room is 18ft x 15ft with a 6ft 5in ceiling, it's in my cellar. Essentially it's a 15ft square room (bad news!) with a bay to extend one side to 18ft. The widebands stand infront of the bay, I find I need the subwoofers in the bay as due to standing waves, if they are further forward I hear no low bass in the listening position.

I believe I have 3 ways forward:

1) leave well alone now, the sound is good (but can always be better!)

2) move one subwoofer to a non-symmetrical position - (I will try this when my back recovers - the subs have 15in woofers with heavy cast frames, it's all I can do to lift the cabs made from 25mm birch ply.)

3) make some tube traps (Helmholtz Resonators), this should improve bass in the room corners, but would it change anything in other areas of the room?

[Darren]

Hi Clive, what frequencies are your subs cut off points? Have you considered time delay issues with your current placement?

[Clive]

Hi Clive, what frequencies are your subs cut off points? Have you considered time delay issues with your current placement?

Well thanks Darren for giving me even more to think about!

The subs go down to around 30Hz before rolling off and I have the upper cuttoff at around 80Hz. The placement of the subs isn't unusual, indeed like many I've found that subs sound better against a wall (or better in a corner) and that I prefer the rest of the music to come from speakers in free space.

If by doing the above I'm introducing time delay (probably yes) then I suspect that for me it's a lesser of two evils. At least that's what I'm telling myself so I won't worry about it! Actually the time delay issue reminds me....I connect my subs at line level, those who connect at speaker-level have the bass travelling through 2 ampliers in series, does this introduce a time delay? Maybe the electrons move at the speed of light so it doesn't matter or maybe capacitors etc slow the signal down?

My initial interest was in standing waves, I seem to have some strong standing waves but I appear to have worked around them. Possibly I have nothing to worry about, apart from time delay!

[Paul Barker]

So which full rangers do you use Clive?

[Clive]

Hi Paul,

It's so easy when I can post a link!

The speakers are Bastanis Atlas http://www.bastanis.com/diy/atlas_en.htm

For sure they ain't exactly budget. I suspect the 12 inch "widebands" (100Hz to 8/11kHz) are Emminence based but Robert treats them with oils and uses felt pads to control breakup. The Gemini tweeters are sourced from Eastern Europe somewhere, again their are some mods.

The 15in woofers are very substantial but I've not worked out who makes them.

[Darren]

It's so easy when I can post a link!

Yes it feels quite odd to be able to include links, but certainly helps to get the message over.

[ed]

Hi Clive

try some of the links from Ethan Winer's homepage :

http://www.ethanwiner.com/articles.html

I've had this discussion with PB on another forum...from experience I know that the same kit sounds completely different(I mean fundamentally) in differing environments, mainly from observation of my PA systems in different venues......but...In the early days of setting up my project studio I experimented with all sorts of reflection compensation and trapping....

IMO and experience, placement and treatment really do change the nature of the equipment.....experiment with the cheaper stuff, there are no hard and fast rules without the room analysis equipment, its fun and its mind blowing.....

regards

Ed

[Clive]

Thanks Ed, that's a useful link.

Clive