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Hi,
is there a standard answer to this that I've missed ? I've moved these 3-way/12"-woof cabs out from the wall as much as the room permits. They're on makeshift eight-inch high stands, tipped back in the stand about ten degrees from perpendicular to floor.
I know furniture and wall hangings can help, I would pull them out another two inches if that would do anything, I would change stands, I would even do some internal bracing if that would do anything...
Surely I'm missing something, since I can't turn them up very much without feeling like being in a resonant tunnel...
(Oh, yeah, they're Stephens Trusonic spkrs, too loud at most levels on a whole 8 watts rms out of a solidstate amp. They're on the long wall of an 18x12 room, maybe 18" out from back wall. Firing as much as I can manage at a soft upholstered loveseat. Oriental rug just in front of spkrs. Downstairs neighbor is at the beach for the summer, now would be the time for being crank-able...)
Thanks for any thoughts.
Follow Ups:
Assuming the floor itself isn't resonating, and the boom is due to phase reinforcement from the room dimensions, you could identify the problem frequencies with a test disc and SPL meter (or an RTA if available), and apply parametric EQ to cut power to the frequencies that boom. Or use a system like Audyssey that does both.
There will probably also be response dips from phase cancellation at certain frequencies, but those are harder to fix. Just throwing more power at them will mostly strain your amp and speakers, since it's still a subtractive phenomenon.
Hi
Room resonances and wall diaphragmatic modes generally cause notches in the low frequency frequency response and not as often peaks.
Their presence can make the range between the notches sound exaggerated but there is something else that can cause what your describing.
The low frequency response of a woofer is strongly governed by the damping exerted on the cone and as this is very predominately the source impedance so there is something else to look at..
If you are using a tube amplifier especially one without negative feed back, there will be less damping and that can cause a peaked LF response which will sound boomy.
Alternately, if the magnet has partially demagnetized, that will also raise the Qb of the system driven by any amplifier.
If you can take the speakers outside and listen, you can find out if it is a room effect or the speaker and amplifier that has produced "that sound".
Best,
Tom Danley
Danley Sound Labs
Thanks Tom D, interesting. I've tried these with an SE Ultralinear tube amp @ 8 watts, a solidstate 10 watt, and a big Yamaha that will do 100 watts in AB, switchable to 20 in class A.
The class A on the Yamaha --which has pretty high damping--- is the best, but still the room predominates, and it's pretty obvious.
You may have something with the partially demagnetized thing, these are old speaker systems. But again, one gets the feeling that taking these into differently built/ appointed room is what is required. That may be the consequence, these have sweet-sounding, nicely vintagey timbre, but-- if you can't turn them up, they're better off playing background music in some bookshop somewhere.
Do they have bookshops still ?
Thanks, B7
I believe Paul W. Klipsch once said that the speaker accounts for about 10% and the room about 90% of the sound of an audio system. (The numbers might be 80% room, 20% speaker, but you get the idea).
Before building any stands or sandboxes (either of which might help), I'd just move the speakers and your listening chair around to every place you can in the room. Disregard where you think the speakers have to go and just experiment! The goal is to discover whether the boominess can be cured by any placements of speakers or listening chair. If the speakers never sound good in any positions you can find, it may be time to look for different speakers. In my own experiments, moving speakers just a few inches can change the sound to a remarkable degree.
Good luck!
George
Yes, thanks, George, this is good advice.
I'll try a few more positions as you suggest. And I'll trying varying the height and angle at each new position.
The limiting factors, since this is reality based, is that they can't be beneath the windows, they'll get rained on, and they can't place the electronics beneath the windows, they'll get dusted, fogged, rained on, etc. They can't be in front of doorways --of which there are four in the room--- or again, force the electronics to be there either. And speaker cables can only be so long, after all. These are for real and can't be ruled out under the higher aim of Audiophile Denial.
Nonetheless, there are probably an easy dozen other ways to try the room & spkrs, so : enough excuses.
there's some good advice on acoustisoft.com.
basically, not only moving the speakers, but also moving your listening spot to get away from walls. you may need to go 'near field' i.e., chair a third of the way into the room and only a couple of meters from the speakers.
moving the woofers a different distance from the floor could help too
Can you give more information about the speakers? Googling gives a LOT of different possibilities. Pictures would be nice!
Definitely try to move the speakers about and try to get uneven distances to the various walls. I second the sand box possibility.
I totally transformed an old set of boomy speakers by applying internal bracing, internal coating, and stuffing…but I don't know what yours have inside.
As below, Trusonic JR200M is the model, a pretty standard looking 12"-woofer 3 way from the seventies.
Interiors are an interesting proposition, since the drivers were sort of cemented in place by a kind of black hard-plaster material. As the baffles are composed of thick chipboard, I can very well visualize "liberating" variably-sized chunks of baffle as the attempt is made to pry the drivers out. Cabinet backs are sealed.
Visible in the port is wadded acoustic damping material, looking like fiberglas, and a lot of it.
compressing a piece of a cheap car wash sponge and placing it in the port (being careful not to push the original filling back).
The Trusonic speakers I saw in the 70's had thick fancy foam grills (like the ones on JBL L-100's), which may have further damped the ports.
I'll give that a try.
Although, I'm not trying for less bass or less low bass, I'm trying for less boom. But every tool is definitely worth trying.And yes, at one time these had those weird, extruded foam grilles; in lurid colors, too.
I always remind myself about that as regards dispersion and treble response-- those things must have shaved a lot off the presence end of things.But that was before my time, and thankfully they went away and the grille frames are still here.
Covered in simple, black, speaker cloth. Black --it's the new lurid.
Thanks.
Edits: 07/21/14
accessory for many speakers (to allow close to the front/speaker wall placement with reduced BASS BOOM).
I gather (from your comment about the VIVID foam grills) that your living/listening room does not have shag carpeting (the Royal Blue grills were @ one time all-the-rave with Green shag;-).
Too bad about the captive cab backs, and speaker gunk, as adding a little bit of fiberglass filling (or whatever is a suitable sub for such now) would probably help remedy the BOOM.
As an experiment only (if you don't have a cheap/foam type sponge on hand you could try placing a piece of duct tape (or similar strong tape) over a portion of the ports to see if the added resistance helps @ all.
using the "Trusonic" namesake they purchased when Stephens was sold.
Is the name Stephens printed anywhere on your speakers and/or the drivers?
Think you're right; these are seventies era 3-ways and have only the Trusonic name on the cabs, not Stephens. JR200M is the model, and it's Indiana not California.
They are efficient, domed-tweeter, paper-coned mids & woofs with fabric surrounds. In general shape, size, and overall aspect, like a Jbl clone.
multiply that distance by 1.5 and 2.25 and try those two distances for to the side wall and to the rear wall, from the woofer's centre
This is IIRC called 'unequal distance spacing'. This - ought - to minimise room-boom.
My floors are suspended 1970s timber floors. Pinus radiata over hard-wood joists and brick piers in concrete.
Depending on the room's width as you listen you may need to swap the ratios about. In my room the distance to the side wall is 1.5 times, and to the rear wall 1.5 times 1.5 = 2.25. If your room is large you might prefer 2.25 to the side walls.
Then you can try making the ratios 1:1.6:2.56 which is ~2.6 anyway
Warmest
Tim Bailey
Skeptical Measurer & Audio Scrounger
When I had a Trampoline floor I put my speakers on 4" deep sandboxes. Cured the boomy bass AND greatly improved mid range definition.
It's hard to say what the answer might be at this point in time. If you are absolutely sure that the speakers can go nowhere else in the room then I would suggest that you continue furnishing the room in the "normal" fashion, and as quickly as possible.It sounds as if the importance of speakers is subordinate to the importance of home furnishings in this case. You won't know how good or bad the speakers can sound until you finish crowding in all of the other furnishings. You might even get lucky and find out that the system sounds better with all sorts of junk thrown around it.
Edits: 07/20/14
Ah, sorry, should have said. We're furnished. Anything we would add would be for acoustics & damping down the boom factor ...
Really just wondered if there was anything other than the standard fixes.
I keep thinking maybe some kind of wide rigid plate/ pad/ blocks under the speakerstands, to damp the floorboards a bit .....?
Auralex makes "MoPads" and other types of isolation platforms for speakers, in a few different sizes and styles, so check them out as they are known to be effective and relatively cheap.
Edits: 07/20/14
My speakers, while not gigantic, are admittedly rather hefty boxes that might be a little large for the room. In addition to stuffing the bottom chamber to capacity with fiber-fill and elongating the port tube, I also have an Auralex Gramma under each speaker and it did help to provide more controlled, more focused bass than before.
The Grammas look kind of DIY...you could probably make something like that, but it might help.
You could also try raising your speakers up on a 12" platform. Changing the woofer height sometimes excites fewer (or different) annoying vertical room modes. It might lighten up and clean up the bass too.
Yes, thanks, that is an easy thing to test.
I can round up a few cinderblocks to test the idea, then consider different stands if successful.
which usually come from "wailing" walls, but I guess old wood floors that are not properly secured could do that too.
Observe, before you think. Think before you open your yap. Act on the basis of experience.
do you have an area rug that you can use? The more you can isolate the speaker cabinets from the floor, the better. Try it. Place something on the walls.
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