A 94dB+ DIY Speaker

[robertm]

Can I get some recommendations on a minimum 94 dB efficiency speaker design to be driven by a 10W tube amp? Drivers and crossovers under $300, I'll build the cabinets, but don't want them to be too challenging. Thanks.

[mzisserson]

Re: A 94dB+ DIY Speaker

Although the first thought is to go large. I always pictured 4 of these in an WWTWW arrangement with good high eff. tweeter like the fostex FT48. You will lose some eff in the final design, but you should have more than enough if you wire to in series/parallel for a final eff of 4 ohms. Tall skinny bookshelf, or a tall skinny tower.

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=264-828

Drivers get you to $200, $225... The rest if up to you.

[Æ]

Re: A 94dB+ DIY Speaker

Not difficult to get 94dB efficiency, but $300 isn't likely to fill the bill.
You're going to have to build it big and probably full range.
Maybe try something from here:

http://www.commonsenseaudio.com/nirvana.html

[Jeff B.]

Re: A 94dB+ DIY Speaker

Although the first thought is to go large. I always pictured 4 of these in an WWTWW arrangement with good high eff. tweeter like the fostex FT48. You will lose some eff in the final design, but you should have more than enough if you wire to in series/parallel for a final eff of 4 ohms. Tall skinny bookshelf, or a tall skinny tower.

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=264-828

Drivers get you to $200, $225... The rest if up to you.

I don't see how this driver could be a good option for the design in question. With 4 in series/parallel you only get to 93dB without any insertion losses. A typical crossover will likely bring it closer to 91dB, with any baffle step compensation, significantly lower than that.....and you're still at 4 ohms, and you don't know if this tube amp can drive a 4 ohm load OK. And this doesn't even address the lack of bass extension. There would seem to be much better options out there; this one doesn't even get in the ballpark.

[Pete Schumacher]

Re: A 94dB+ DIY Speaker

Can I get some recommendations on a minimum 94 dB efficiency speaker design to be driven by a 10W tube amp? Drivers and crossovers under $300, I'll build the cabinets, but don't want them to be too challenging. Thanks.

High sensitivity comes at the cost of larger cabinetry, unless you don't care about bass extension. If you want 94dB, 8 Ohm and 40Hz, you're going to be in the large cabinet category, and therefore, more challenging to build.

If you don't mind filling in the stuff below 120Hz with a sub, you could opt for a set of small line arrays using some buyout drivers.

[spasticteapot]

Re: A 94dB+ DIY Speaker

Have a look at a pair of these - with the right woofer, you should be able to hit 93dB efficiency.

http://www.audiokarma.org/forums/showthread.php?t=150939

I'm not so sure about the "default crossover design", so I'd consider designing your own (or asking someone here to help you.) However, with a pair of inexpensive pro-style 10" or 12" woofers (or preferably two of them), you should be able to hit your efficiency target. One of the nifty things about waveguides is that they place the "acoustic center" of the driver much further back, making it easier to keep it in phase with a great big woofer.

Another of the advantages of waveguides is that you can corner load them without nasty room reflections. By placing your loudspeakers in the corners of your room, you can greatly increase bass efficiency and eliminate power-hogging baffle step response compensation. Were you to build some traditional "corner horns", you might be able to attain efficiency of 96dB or greater.

A lot of folks like the inexpensive ($60) Eminence Alpha 15 driver, which I'm told can make the 1khz crossover point without much difficulty. However, since you're not running this open-baffle, I'd consider looking at the slightly more expensive ($90) Emincence Delta, which has a more heavy-duty magnet structure and is even more efficient!

[mzisserson]

Re: A 94dB+ DIY Speaker

I don't see how this driver could be a good option for the design in question. With 4 in series/parallel you only get to 93dB without any insertion losses. A typical crossover will likely bring it closer to 91dB, with any baffle step compensation, significantly lower than that.....and you're still at 4 ohms, and you don't know if this tube amp can drive a 4 ohm load OK. And this doesn't even address the lack of bass extension. There would seem to be much better options out there; this one doesn't even get in the ballpark.

I am embarrassed, you are correct. I calculated at 2.83V, which you end up a little over 96dB. :o

I have modeled these in an MTM (never built and tested however) and F3's in the mid 40's is easily achievable. Good bass extension if you ask me. Also starting at 90dB with an 8 ohm load was great for the application I was desling with.

You would be hard pressed to find a tube amp without a 4 ohm tap.

[spasticteapot]

Re: A 94dB+ DIY Speaker

If you're set against using any form of horn or waveguide, a 3-way of efficient drivers would do the job. Many people have had great success with the Eminence Alpha 6A midrange driver (including, if I recall, a few folks on this forum), which, combined with one of the great big woofers above and a nice tweeter (say, Vifa DX25?), would make a dandy 3-way.

[hoxuanduc]

Re: A 94dB+ DIY Speaker

Can I get some recommendations on a minimum 94 dB efficiency speaker design to be driven by a 10W tube amp? Drivers and crossovers under $300, I'll build the cabinets, but don't want them to be too challenging. Thanks.

I think the 2 Pi Tower would fit your needs. 95db efficient and less than $200 a pair plus shipping & box. I'm not affiliated with Pi speakers, just a happy customer. You can email Wayne for plan and schematic and buy the parts at PE. I just ordered the whole kit from him.

http://www.pispeakers.com/Prices.html

Happy New Year!!!

Duc

[DS-21]

Re: A 94dB+ DIY Speaker

Look on the various Econowave threads here and elsewhere.

And you might want to consider a higher-performance amplifier with your high-efficiency speakers.

[rudyjakubin]

Re: A 94dB+ DIY Speaker

Can I get some recommendations on a minimum 94 dB efficiency speaker design to be driven by a 10W tube amp? Drivers and crossovers under $300, I'll build the cabinets, but don't want them to be too challenging. Thanks.

I'm listening to a 102 db 16 ohm set right now. It's a 12" 2-way inspired by the really nice fellers at AudioKarma.
My review is here;

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=290-826

There's cheaper 12's and even ten's that'll work.
I'm a tubey doobey guy myself (100watts0...
I had my pair play through a Logitech amp powered by a wallwart and it sounded fantastic and movies were a blast.

[spasticteapot]

Re: A 94dB+ DIY Speaker

Those Pi Acoustics speakers look kinda sketchy. From what I'm reading, you don't even get a proper tweeter unless you pay for an upgrade - you get a piezo. Furthermore, neither of those tweeters are suitable for use with a 10" woofer - power response is going to be a bit weird, if nothing else. I'm also not entirely keen on his heavy use of front-loaded horns.

However, you could probably build something similar using the drivers I've linked to - to be honest, a 12" would probably work better with the Econo-Waveguide design I linked to than a 15" driver, and if corner-loaded should provide more than adequate bass in a simple ported enclosure.

However, if you want something along those lines that's not sucky, consider any of Bill Fitzmaurice's PA designs. They're a bugger to build (sorry, Bill, but it's true) and if you don't do it right the results will suffer, but if you're willing to put in the elbow grease, I'm told they provide very impressive results with truly monumental efficiency.

I'm listening to a 102 db 16 ohm set right now. It's a 12" 2-way inspired by the really nice fellers at AudioKarma.
My review is here;

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=290-826

I would very strongly recommend NOT using a guitar speaker for anything but a guitar. They berserk above a few Khz, and are intentionally designed for high harmonic distortion. In short, bad choice.

[hoxuanduc]

Re: A 94dB+ DIY Speaker

Those Pi Acoustics speakers look kinda sketchy. From what I'm reading, you don't even get a proper tweeter unless you pay for an upgrade - you get a piezo. Furthermore, neither of those tweeters are suitable for use with a 10" woofer - power response is going to be a bit weird, if nothing else. I'm also not entirely keen on his heavy use of front-loaded horns.

However, you could probably build something similar using the drivers I've linked to - to be honest, a 12" would probably work better with the Econo-Waveguide design I linked to than a 15" driver, and if corner-loaded should provide more than adequate bass in a simple ported enclosure.

However, if you want something along those lines that's not sucky, consider any of Bill Fitzmaurice's PA designs. They're a bugger to build (sorry, Bill, but it's true) and if you don't do it right the results will suffer, but if you're willing to put in the elbow grease, I'm told they provide very impressive results with truly monumental efficiency.

I would very strongly recommend NOT using a guitar speaker for anything but a guitar. They berserk above a few Khz, and are intentionally designed for high harmonic distortion. In short, bad choice.

Years ago, that was true. Now the Pi 1 and 2 come standard with the Vifa DX25. I prefer the Pi 2 to the Natalie P and some others that I also built. Pi speakers' model 3 and 4 are very similar to the E-Wave design, but they're above the budget stated in the OP.

Thanks,

Duc

[Æ]

Re: A 94dB+ DIY Speaker

Check out the "Whamodynes" at the Bottlehead Forum, they use them with low power tube amps.

http://www.bottlehead.com/valve/whamodyne%20files/page2.html

[billfitzmaurice]

Re: A 94dB+ DIY Speaker

Can I get some recommendations on a minimum 94 dB efficiency speaker design to be driven by a 10W tube amp? Drivers and crossovers under $300, I'll build the cabinets, but don't want them to be too challenging. Thanks.

For above 100 Hz it's not all that difficult, you can get there with quite a few MTMs, especially as driving 4 ohm loads with tubes is no problem. Below 100 Hz it's a different story. If you've got a woofer capable of getting to even 40 Hz with that much sensitivity it's going to take a good sized box. Other options are either horn loading or lots of smaller woofers, but no matter what the route the system size isn't going to be small.