Die Hard 4.0 with the Lab5 is the best! My sofa vibrates...and not only a little bit :-)
Karsten
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Most peculiar Lab5 Vibrations
36 replies
not wanting to go too off topic but the bridge scene in Mission Impossible 3 is awesome (volume 70) 😮
much better with lab 5s than beolab 2..
In response to Kawo's post about Audissey, my business partner Manny LaCarrubba undertook a study of various room correction systems as part of a project we are currently working on. Audissey was one of the systems - it is a full bandwidth system and Manny's conclusion is that it works OK, and has a nice user interface, but that he prefers the outcomes obtained by some of the other systems under test better.
In this case, the problem is clearly a low-frequency problem and ABC should handle it quite well. The fact that it doesn't appear to be handling it well suggests to me that the entire floor is being excited, resulting in a large vibrating membrane (the floor) whose response cannot be adequately controlled by altering the response of the exciters (the BL5s). Hence my suggestion of floor supports directly under each speaker, to restrict floor motion at the speakers, effectively making them nodes. This should help.
In general, I do not support the idea of overlaying two room correction systems – I can imagine serious interactions and unanticipated consequences. Given Kawo's excellent system, I'm not at all sure that Audissey would yield much if any improvement, while it might actually degrade the performance of the BL 5s.
I hope this helps.
Best regards,
Dave,
would setting a cross-over with Audyssey or another system above that handled by the BL5s for the rest of the frequency range be advisable?
Peterjacobs did you find a solution?
Ok all, thanks for all your responses and debates especially Dave Moulton.
I went off to our local DIY store and got 4 650 mm square concrete pavers.Two sandwiched together to make a concrete plinth about 5 inches high. Placed the Lab 5s on these. Re calibrated and then used a couple of B&O demo CDs to test any change. I also played the DTS DVD Terminator 3. Not much change at all. Interestingly I did noticed by standing right next to the lab 5s that (when they were on the concrete plinths and without being on them too) that when the calibration sequence started for the bass frequencies I could lliterally feel the floor boards deflecting.
Now Dave Moulton asked a very focussed question. The size of the joists supporting the floor. Well, (don't do this at home) I had to go off to our local pest control, get some "spider dispersal bombs" let them off under the house. Then wait an hour before crawling underneath. The gap is just over 24". The floor joists are solid hardwood, 6" x 8". The floor itself is solid hardwood boards 3/4" thick.
So, I took the lab5s off the plinths, then placed the US "Big Fat Dots" speaker vibration damping pads (note these can be used for speakers up to 90 kilos). Re calibrated, then played the same tracks and DVD.
Result - A HUGE DIFFERENCE, POSITIVE of course. I anticipated that it would be better, as when I started the calibration I stood next to the speakers and did not notice MUCH deflection of the floor boars all though there was a hint of it. I re calibrated again and this time sort of leaned on the larger aluminium disc of the lab 5s. Now no deflection of the floors.
End result, the 5s are back to their best. !!!!!!!
I actually took a day off work today to enjoy them, just to celebrate.
Herbies Audio Lab. They are on the web. $ US 70 + $US 25 postage to Australia. for 10 discs. $ placed in a square and one in the centre.
Hope this helps anyone else with the same problem.
Peter
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