[Chopper87]

Hi guys/Gals.  I am thoroughly enjoying my Lowther PM2MKII/Tone Tubby 12" Alnico Open Baffle setup quite a bit.  I am curious if there is really much benefit in dampening the back of the OB with something like felt?  Will doing this offer a noticable sonic upgrade or is it not worth the effort?  Thanks for the advice.

Lance

[HiFiNutNut]

If you are referring to adding damping to the back of your existing OB speakers that you are already happy with, I would expect that the damping would alter the response. Whether it is to the better or worse can only be found out through experiments.

If for a brand new design, I can see the merit of adding damping to the back of a OB, at least in theory. My next speakers will be U-frame dampped OB. I will only find out if I like it better when I built the thing. I can see all the advantages and disadvantages in theory, and in general, advantages over disadvantages.

Regards,
Bill

[D OB G]

I had Quad ESLs many years ago (the originals) and very good they were too.

They had a layer of felt a mere few mm behind the dust cover.

I wondered what would hapen if I removed it, which entailed leaving the kV charged membrane exposed!!  I was single at the time!!!

The sound really improved, especially the dynamics, with a slight loss in bass.

But that really was an exceptional case, because I don't believe they truly worked as open baffles at higher frequencies.
More like a cardioid pattern maybe.

Anyway, I suppose it's all about experimentation.

David

[Brad]

Very good question.

My homemade baffles for the Hawthorne Duets were not damped on the back.
The (much nicer) pair I had Hawthorne make is damped on the back.

I found the sound to be cleaner,  but it still has the OB room filling ambience.

Probably one of those cases that could work either way, depending on your system and room (and baffles)

[hurdy_gurdyman]

Are we talking about putting felt behind the drivers to damp the drivers output or putting felt on the baffle itself to damp reflections?

Dave

[TerryO]

Back in the old days there were a lot of open back speakers, and it wasn't uncommon for the manufacturer to hang a felt curtain inside suspended from the top. It worked in those days and unless the sound waves have mutated, it should still work. An old woolen Army Blanket or thin carpet pad (or even a beach towel) should allow you to experiment.
If OTOH you want to damp the back of the baffle itself, use rubber cement to glue the felt (or whatever) down, it's reversable and can be peeled off later if necessary.

The question is: What's holding you back?

Best Regards,
TerryO