Waveguide effect on speaker efficiency

[DJNUBZ]

Just a quick question. Is there an increase in a dome tweeter's efficiency when it is loaded in a wave guide? If so how much of an increase is there?

[DJNUBZ]

Can someone tell me about this or give me a link to the answer?

[DougL]

Zaph did a test of a wave guide dome tweeter.

As long as the wave guide holds pattern control, the frequencies below where the tweeter starts to beam show a modest rise in output, simply because the waveguide prevents 2Pi radiation. The extent depends on the geometry of the waveguide.

HTH

Doug

[Andrew Eckhardt]

The inclusion of a compression chamber is where horns start to show a major increase in power efficiency. With a waveguide on a direct radiator the apparent (and arguably true, so long as you're sitting in the hot spot) efficiency increases because the sound pressure is gathered in a smaller area. I don't think overall acoustic output power increases.

[Flaesh]

conical, without comp. chamber

[gedlee]

Originally Posted by DJNUBZ

Just a quick question. Is there an increase in a dome tweeter's efficiency when it is loaded in a wave guide? If so how much of an increase is there?

It's not a simple answer because it varies with frequency, horn style ... most of the parameters. Basically a lower frequencies, but above what is usually called the "cutoff" (although the term is misleading) there is an increase in efficiency. But this increase fall off to zero as the frequency goes up ending up at almost no change in efficiency.

But be carefull that you understand and mean "efficiency" because it's not sensitivity or SPL - those act entirely differently because of the changes in directivity.

[DJNUBZ]

I understand and I should have asked if waveguides have any affect on sensitivity. I am trying to find a tweeter that is 96db/watt/meters which is hard to do. I was hoping that a waveguide might help me find a tweeter which may be 93db/watt/meters and increase it's sensitivity. I understand the many other benefits of waveguides but I am not so sure it will help me here.

Gedlee I was wondering if you have tried any SET amps with your speakers and how well it worked. I have a Decware Zen amp and I currently have a pair of parker audio 98's I am looking to find a pair of speakers that mates well with my amp but performs more to the level of sound quality I am looking for.

[gedlee]

Originally Posted by DJNUBZ

Gedlee I was wondering if you have tried any SET amps with your speakers and how well it worked.

Me? You don't know me very well I guess. I'd use an IPod if thats all I had, and I permanately use a simple Pioneer Receiver. I don't buy the amp thing. But you are quite correct that 96 dB is very hard to do without a waveguide and with a SET you are going to need a very high senitivity. A lot of others use SETs and seem to like them.

But here is the problem. Yes, the waveguide will increase sensitivity of a tweeter, but onlt at the low end. This means that if it 93 dB at the 10 kHz, you can't get above that. You'll get a lot of gain at the low end, and this helps a lot with power handling and excursion, but you can't really extend the sensitivity beyond its high frequency level.

[head_unit]

Yeah, it's tough to get 96 dB without some kind of "horn" type device. Orca might sell some ribbons that sensitive, but pricey.

Probably you need to explain more what you are trying to do (i.e. what is the rest of the system? What frequency range are you looking for?) to get more helpful hints.

[br85]

Short answer: No. The apparent increase to sensitivity is only over a small range of frequencies, and if you want to use that for anything, it is to try and combat low end roll-off in order to chase a lower crossover frequency.

I.e. you might get +5db axial sensitivity at 1.5khz, +3db at 3khz, and +1db @ 4khz, but anything higher than that will receive no "gain" whatsoever in a given waveguide.