redfuneral - Current reply excepted, you've heard from some very involved and competent folks so far and they really do know their stuff. I also know this might not be what you'd requested, but this situation sure sounds like it could be better (and maybe more inexpensively) addressed by acquiring an appropriate fan or even a quiet air conditioner...
Heat/Efficency of Speakers
What % of power sent to the speakers is turned to waste heat? That's the short version of my question.
I'm looking to minimize waste heat accross my stereo as my listening room is unforgiving come summer; no cooling and a computer system which cannot be relocated. I understand amplifier efficency & the classes as well as speaker efficency measured as W/db however the interplay eludes me.
Taking two hypothetical amplifiers: a Class A amplifier outputting 10W w/ 100W from the wall & a Class D outputting 200 w/ 220W draw I understand the D will be the cooler operator however this is where the discussion tends to end, D only wasting 20W vs the A amplifier's 90W. Considering appropriate speaker matches to each amp(as well as a standard HE speaker at say 95db/w), how do I determine the wattage converted sound and the watts spent as heat?
I'm asking because I was previously running a 10W tube amplifier in this room(4xel84 tubes) with 96db speakers. This was bearable in two hour doses this last summer. My friend assures me any Class D amplifier and many AB amps would have no such heating problems and says it's class not wattage that is my issue. Before I move to a different amplifier technology(and swap speakers, these voiced for SE tube partnering) I want to understand this issue fully. I'm unconcerned with power usage and only care about the heat.
I'm looking to minimize waste heat accross my stereo as my listening room is unforgiving come summer; no cooling and a computer system which cannot be relocated. I understand amplifier efficency & the classes as well as speaker efficency measured as W/db however the interplay eludes me.
Taking two hypothetical amplifiers: a Class A amplifier outputting 10W w/ 100W from the wall & a Class D outputting 200 w/ 220W draw I understand the D will be the cooler operator however this is where the discussion tends to end, D only wasting 20W vs the A amplifier's 90W. Considering appropriate speaker matches to each amp(as well as a standard HE speaker at say 95db/w), how do I determine the wattage converted sound and the watts spent as heat?
I'm asking because I was previously running a 10W tube amplifier in this room(4xel84 tubes) with 96db speakers. This was bearable in two hour doses this last summer. My friend assures me any Class D amplifier and many AB amps would have no such heating problems and says it's class not wattage that is my issue. Before I move to a different amplifier technology(and swap speakers, these voiced for SE tube partnering) I want to understand this issue fully. I'm unconcerned with power usage and only care about the heat.
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- 29 posts total
redfuneral, I don't know where you are, but I understand your dilemma...somewhat. I'm in Phoenix, and for some reason the room I chose in the house for my office doesn't seem to get as much AC airflow as some of the other rooms. From June through September, my office can be uncomfortably warm. I bought a Peachtree integrated, based on Class D amplification, specifically for summer use so that I could enjoy music without adding to my heat problem. I'm very happy with it and now use it year-round (I also have an Audio Research tube integrated but don't use it). I'm no engineer so I can't give you the technicals, all I can do is echo what others have said - it runs cool, sounds great, and takes up very little space. Your friend steered you in the right direction with the Class D recommendation. |
shadorne You might want to check your reading comprehension while I am checking my math!But that's not what you wrote: Speakers typically churn out between 99% and 90% of energy as heat.I don't know of any speaker that's 90 percent efficient. That's why I wrote: most speakers are much less efficient than that. A speaker with 92 dB sensitivity is only about 1 percent efficient. |
Not a scientific response from me by any means but frankly I would not worry about how much thermal energy your speakers put out. Grab a sensitive measuring device and measure the air a few feet away from the speakers and right next to the speakers; I'd bet there is no meaningful variance in temperature (i.e. higher) right next to the speaker. You have to measure close in I would guess so you don't confuse the effect in that immediate area from your amp. If you are worried about speaker-produced heat, you should also be questioning how much heat your components and rack throw out as most isolation racks & platforms work on the principle of harnessing kinetic energy (vibration) and channeling it away as thermal... The biggest concern is heat energy from tube and solid state gear, or hybrid (solid state with tube input and/or output stages, power supplies, etc...). In general class A and tubes of any kind are the worst with Class AB and ICE or Class D being the best in terms of producing little heat. The person who mentioned 'idling' characteristics is spot on... Playing devil's advocate for a minute; if you have sound you like from gear and speakers that you like, instead of ditching the gear, taking a loss on the used market sale then buying-in again all from the beginning (speakers, amps, etc...), why not put a smaller some into a separate "split" heat-pump unit (so heat as well as A/C) for that room only. A split is a unit with a very quiet unit mounted in-wall with no duct work and the compressor/heat exchanger mounted outside on a concrete pad....just a suggestion. |
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