Soffit mount transmission line speakers (PMC)

[Xen Ochren]

I too have been looking into this for TB2's.

The australian sales rep informed me that soffit mounting was unadvisable as the speakers will overheat. There needs to be adequate ventilation behind them.

that being said i am using the passives...

so i think I will go with in wall mounting, but with plenty of ventilation, mainly for the reflection advantages of in wall mounting.

[Soundman2020]

The australian sales rep informed me that soffit mounting was unadvisable as the speakers will overheat. There needs to be adequate ventilation behind them.

If overheating is the only issue then there is no problem! A correctly designed soffit for active speakers (such as the designs on this forum) always includes ventilation. Surprising that the rep didn't know that.


- Stuart -

[gullfo]

even without an active monitor you want venting because the speakers in use will generate heat...

[Xen Ochren]

got this from the UK rep

"HI Evan, I would not recommend soffit mounting the TB2 speakers. This is mainly due to the fact that the TB2 has a rear vent.
 
Soffitt mounting is a tricky one with any speaker, if not carefully designed can cause more problems than benefits


Avoid in wall mounting like the plague! Unless you get an acoustician involved."

[Xen Ochren]

Just spoke to him on the phone (ill find out what the international call costs in a few weeks)

he stressed that it was ok to soffit mount the TB2's, just his issue was that he has seen it done incorrectly many times.

which really just leaves me with the problem of the bass boost.

the TB2's are already fairly bassy, so it may become too much.

when talking with him about eqing or filters, he said the active model have a roll off which could be used, but i have the passives which have none. He was saying that adding eq will add phasing and other issues,

so it seems to me it is just a trade off of issues? benefits of soffit mounting versus problems of the bass boost?

wish i had the actives...

[hansaffe]

you´re not alone


i got the same problem with my IB1s

[hansaffe]

maybe you want to have a look on my thread here how i managed to soffit mount my passive IB1

http://www.johnlsayers.com/phpBB2/viewt ... =1&t=16399

but without ventilation...

just have a look... maybe you find something useful

cheers

Andi

[DeeDee]

even without an active monitor you want venting because the speakers in use will generate heat...

Even if the monitor in question is a closed box, or front ported? I've never noticed my bass speaker cab get warm on the outside (and its absorbing 500+ watts)

Cheers,

[Soundman2020]

Even if the monitor in question is a closed box, or front ported? I've never noticed my bass speaker cab get warm on the outside (and its absorbing 500+ watts)

Right, but is it mounted in a very small sealed soffit, with huge amounts of thermal insulation all around? Right now, your speaker is likely sitting out in the open, exposed to air on all sides (or most sides) so it can easily dissipate those 500 watts into the air. But enclosing it inside a box that isn't much bigger than it is, then surrounding it with many inches of insulation, is a different story. Try tucking a couple of really thick blankets around it, really tight and really thick, run it for a while at high levels, then put your hand inside the blankets to feel how warm the speaker cabinet itself got.

Don't forget that speakers are very, very inefficient at converting electrical power into sound power: Somewhere around 1% efficient, for a very efficient speaker. So if you are pumping 500 watts of electrical power into that box, likely only about 1 watt of actual sound power is coming out of it, best case, and probably much less than that. The other 499 watts are wasted in many ways, and most of that ends up as heat.

- Stuart -

[DeeDee]

You make a good point.

I have a multimeter with a thermocouple. I'll put the thermocouple on the back of the magnet, stick a 1khz sine wave into the speaker and watch the temperature with the speaker naked, in its usual cab and in a cab buried in blankets. Watch this space...