Higher efficiency designs for SET amps?

[blair]

Hey guys,

Just curious if anyone has any suggestions for 92+db speaker designs for use with SET amps. I would prefer the design be pretty full range somewhere from 40-50hz - 20K if possible. I see tons of single driver sites, but I'm typically not a fan in any way of these types of designs. Audio Nirvana drivers claim to be pretty nice, but I have never heard them thus some hesitation. This is not saying I am eliminating single driver designs either. Please make recommendations based on your tastes and experiences.

BTW, please be reasonable with your suggestions price wise. I'm pretty sure my three way project with the 8848P/Peerless HDS/RS225s will beat any of these design up all over the place minus the sensitivity category.

The reason for needing these speakers is that I really enjoy building SET and SEP amps, and need comething to demo them with to people interested in hearing them.

Thanks for any suggestions!

Blair

[billfitzmaurice]

High efficiency pretty much boils down to horns and line arrays. Horns are a complicated build and are big. Line arrays are easy enough to build but lots of drivers means they can get expensive. Horns and line arrays will do 100dB/watt and more; in the world of high efficiency afficionados 92dB doesn't even qualify.

[Pete Schumacher ®]

Hey guys,

Just curious if anyone has any suggestions for 92+db speaker designs for use with SET amps. I would prefer the design be pretty full range somewhere from 40-50hz - 20K if possible. I see tons of single driver sites, but I'm typically not a fan in any way of these types of designs. Audio Nirvana drivers claim to be pretty nice, but I have never heard them thus some hesitation. This is not saying I am eliminating single driver designs either. Please make recommendations based on your tastes and experiences.

BTW, please be reasonable with your suggestions price wise. I'm pretty sure my three way project with the 8848P/Peerless HDS/RS225s will beat any of these design up all over the place minus the sensitivity category.

The reason for needing these speakers is that I really enjoy building SET and SEP amps, and need comething to demo them with to people interested in hearing them.

Thanks for any suggestions!

Blair

Start with a Pro woofer from AESpeakers or Eminence. Augerpro has some very good data on his page concerning high sensitivity woofers up to 15".

You could pair the AESpeakers TD12M (http://aespeakers.com/shop/catalog/product_info.php?cPath=23&products_id=60) with a higher sensitivity dome tweeter and build a two way with a reference sensitivity of around 93dB when you factor in a bit of BSC. The SBAcoustics SB29RDC comes to mind as a topper.

Otherwise an MTM using a pair of SB17NRX35 and SBAcoustics SB29RDC tweeter might do the trick for a little less dough.

[terryo]

Blair,
I don't know what you've heard, but if you have the space, a Lowther/ToneTubby 2-way open baffle like those that Jon VerHalen had at the last VSAC might be a real great platform to demo your amplifiers with. They were nice looking and had just about the best sound at the show.
Here's some links to the VSAC show:

http://www.enjoythemusic.com/vsac_2008/

http://www.6moons.com/industryfeatures/vsac20082/vsac.html

http://www.audiocircle.com/circles/index.php?topic=54959.msg491672;topicseen

Best Regards,
TerryO

[blair]

Thanks Bill,

Line arrays are out of the question. I'm not a fan, and yes before a million people jump on the bandwagon, I have heard plenty of them.

Anyway, 92-95db is plenty for most of the SETs and SEPs I build. They are typically KT88s or 6550s and pushing 8-15 watts. I do not build little 1.5w amps for the most part. I have a pair of 90db three ways a pair of SE kt88 monos drove just fine until I sold them. More than enough for me. I was just looking for something with slightly more efficiency than those.

Blair

[Pete Schumacher ®]

Thanks Bill,

Line arrays are out of the question. I'm not a fan, and yes before a million people jump on the bandwagon, I have heard plenty of them.

Anyway, 92-95db is plenty for most of the SETs and SEPs I build. They are typically KT88s or 6550s and pushing 8-15 watts. I do not build little 1.5w amps for the most part. I have a pair of 90db three ways a pair of SE kt88 monos drove just fine until I sold them. More than enough for me. I was just looking for something with slightly more efficiency than those.

Blair

I don't think Bill noticed the trailing "-er" in your thread title . . . ;)

[blair]

Yep Pete,

Upon reading, I suppose it is kind of a rigged question. Besides, I just like building SET/SEP amps. I have a pair of 150w tube amps, and am workng on a pair of SKA 300Ds right now. It is like a sub-station in ly house:eek:

Thank you for your suggestions!

Blair

[xavier]

I've heard one of the Audio Nirvanas installed in a PE cabinet. I believe it was an 8".....maybe a 10". Really remarkable sound considering it's coming from one driver. I heard it back to back with a Jordan driver. The AN sounded warmer and more realistic to me, although I heard a slight abrasive quality in the treble. Might be fine for backround listening, but I know I'd never be able to live with it as a stand alone driver. My roomie has a really nice 10-12W tube amp that I'd like to make speakers for. My first choice is to get an AN driver and make a passive two way with it supported by an active bass driver. (Plate amp along with a Dayton subwoofer in the same cabinet)

[blair]

Thanks,

That is what I have heard about the AN drivers as well in regards to the high frequescy response. I suppose I could roll it off a bit early and supplement with a tweeter to eliminate the high end harshness without losing too much sensitivity. The price is pretty attractive for full range drivers. That is what is drawing me towards it.

Blair

[craigspieker]

I know you said you didn't need ultra high efficiency, but wouldn't it be nice to be able to build some flea watt amps and get away with it. I'm working on a design with a front horn compression driver to run from 800hz on up, mated to a 15" PA driver. But you could also use an ordinary woofer and just run the woofer off a solid state amp while the SET drives the high freq. I would bet the SET sound from 800hz up would be pretty much the same as full range. just a thought, good luck

[blair]

It is a nice thought, and I appreciate all feedback. I'm limited to space issues which is problematic with most super high efficiency designs. These have to flank my current open baffles which are 18" wide roughly.

Blair

[benchtester]

Zaph had nice things to say about the B&C 6MD38-8. A 96dB midrange.

http://www.zaphaudio.com/6.5test/

[Pete Schumacher ®]

It is a nice thought, and I appreciate all feedback. I'm limited to space issues which is problematic with most super high efficiency designs. These have to flank my current open baffles which are 18" wide roughly.

Blair

You can't have high efficiency, bass extension, and small size.

If you want high efficiency and small size, you need to sacrifice low end extension.

[MSaturn]

90dB should be enough even for ridiculously low amount of power. There is no "magic" to having less wattage; a 10w tube amp is going to outperform a 1w amp any day. I've never understood the point of purposefully spending tons of money to get little to no power - which inherently introduces a bunch of distortion due to rapid overload. Look at THD vs. power charts for some 1-2w amps sometime. They're ridiculous.

Note that when you're spending $1000 for 10w of tube power, you're essentially buying the world's most expensive and least efficient space heater, that happens to put out a sub-standard amplifed audio signal as a bonus.

Now a 10-20w tube amp with a 90db+ speaker is going to have that "special tube sound" and not be a bunch of hokum. I've designed a system using that B+C driver zaph tested (the 8") and an XT25 which runs a solid 90dB to 100Hz. It's meant to be used with a sub, though, and I'd be powering it with 50w of good old bipolar transistor power.

[AJ]

90dB should be enough even for ridiculously low amount of power. There is no "magic" to having less wattage; a 10w tube amp is going to outperform a 1w amp any day. I've never understood the point of purposefully spending tons of money to get little to no power - which inherently introduces a bunch of distortion due to rapid overload. Look at THD vs. power charts for some 1-2w amps sometime. They're ridiculous.

Note that when you're spending $1000 for 10w of tube power, you're essentially buying the world's most expensive and least efficient space heater, that happens to put out a sub-standard amplifed audio signal as a bonus.

He's talking about his own amps. It's much cheaper building the amps yourself, and tubes are easy to work with. Whether you like the sound or not depends on what you like.

I think Paul N. O'neal had a high sensitivity design based on the Eminence 15" Kappa Pro LF driver. Like Pete said, i would start with something like that.

[philiparcario]

Hey guys,

Just curious if anyone has any suggestions for 92+db speaker designs for use with SET amps. I would prefer the design be pretty full range somewhere from 40-50hz - 20K if possible. I see tons of single driver sites, but I'm typically not a fan in any way of these types of designs. Audio Nirvana drivers claim to be pretty nice, but I have never heard them thus some hesitation. This is not saying I am eliminating single driver designs either. Please make recommendations based on your tastes and experiences.

BTW, please be reasonable with your suggestions price wise. I'm pretty sure my three way project with the 8848P/Peerless HDS/RS225s will beat any of these design up all over the place minus the sensitivity category.

The reason for needing these speakers is that I really enjoy building SET and SEP amps, and need comething to demo them with to people interested in hearing them.

Thanks for any suggestions!

Blair

this is okay with a super tweeter

http://www.madisound.com/catalog/product_info.php?products_id=271 woofers are
70 each

http://www.madisound.com/catalog/product_info.php?products_id=1399

cabinets are 150 each



the full kit is 850

http://www.madisound.com/catalog/product_info.php?products_id=1325

but 2 woofers and 2 boxes are 450.

you can use lower priced top end tweeters. in fact you can run the kit without a tweeter and still play from 55 to 12000hz without rolloff.

[GordonW]

You can't have high efficiency, bass extension, and small size.

If you want high efficiency and small size, you need to sacrifice low end extension.

As the old commercial said: "That's not only a good idea... it's THE LAW!"

As for a suggestion- given that the cabinet is going to be pretty big to get high efficiency, one of the larger Econowave projects (as described over at AudioKarma, in this thread: http://www.audiokarma.org/forums/showthread.php?t=150939 ) might just do the trick. The Pyle/JBL E-wave horn, Selenium D220Ti horn driver, and something like a Eminence Delta LF 15" in around 6 cubic feet tuned to about 30 Hz, will give solid response from 35-20000 Hz, at around 97 dB sensitivity. If you're willing to use 8 cubic feet, it's flat downt to darn near 30 Hz!

Just use the E-wave highpass (greater than 95dB version, naturally)... but the low pass will need to be modified- I'd start with around a 3mh choke and a 6.2uf cap, with a Zobel of around 15uf and 7 ohms. That should tame down the rising response of the woofer, once it's tuned in, to a quite smooth response...

I just got through building a similar speaker- dual 15" TOA woofers per cabinet, with the E-wave horn and highpass. I will say, that even on a crappy Fisher solid-state amp (not more than 30 watts), that out in my carport, this speaker could EASILY be heard a block away! :D And it was quite detailed- it doesn't sound anything like a PA speaker, despite its looks!

Regards,
Gordon.

[MSaturn]

All I know is, in a hobby full of compromises, watts are way cheaper than horns ..

[philiparcario]

All I know is, in a hobby full of compromises, watts are way cheaper than horns ..

I am with you all the way. I gave up on fostex lowhter etc a long time ago. I felt box size/ horn size became silly so why bother..

also gave up on small deep subs with tons of eq carter type true subs. They don't sound right to my ear and since it is my house my money I want it to sound like bass that I like. Dayton rss390 hf ,nht 1259's, scanspeak 23w's and nht verve sub work fine on that end.

[squib]

If you can fit a very tall (~60"), but narrow cabinet in your space, you might consider Scott Lindgren's Calhoun (http://homepage.mac.com/tlinespeakers/FH/download/calhoun-1v0.pdf)design. It uses two of the CSS WR125's plus a TB tweeter. There are many variations of the basic design at the frugal horn website. I know BVR's are hardly everybody's cup of tea, but they do yield pretty high efficiency.

Main DIYaudio thread (http://www.diyaudio.com/forums/showthread.php?s=&threadid=96937&perpage=25&pagenumber=1)

Frugal-horn (http://www.frugal-horn.com/spawn.html)

[GordonW]

All I know is, in a hobby full of compromises, watts are way cheaper than horns ..

The E-wave horn I mentioned covers the "top half" (1K and up). A high-efficiency 15 covers the "bottom half".

Flare is $13
( http://www.parts-express.com/pe/showdetl.cfm?Partnumber=292-2572&FTR=ph612&CFID=12103578&CFTOKEN=81813276 )

Driver is $41
( http://www.parts-express.com/pe/showdetl.cfm?Partnumber=264-270 )

Woofer is $100
( http://www.parts-express.com/pe/showdetl.cfm?Partnumber=290-417%20%20%20%20%20%20%20%20&FTR=delta%2015%20lfa&CFID=12103578&CFTOKEN=81813276 )

Crossovers can be done for less than $50 each, IIRC...

How much tube amp can you buy for $400? :cool:

Regards,
Gordon.

[philiparcario]

The E-wave horn I mentioned covers the "top half" (1K and up). A high-efficiency 15 covers the "bottom half".

Flare is $13
( http://www.parts-express.com/pe/showdetl.cfm?Partnumber=292-2572&FTR=ph612&CFID=12103578&CFTOKEN=81813276 )

Driver is $41
( http://www.parts-express.com/pe/showdetl.cfm?Partnumber=264-270 )

Woofer is $100
( http://www.parts-express.com/pe/showdetl.cfm?Partnumber=290-417%20%20%20%20%20%20%20%20&FTR=delta%2015%20lfa&CFID=12103578&CFTOKEN=81813276 )

Crossovers can be done for less than $50 each, IIRC...

How much tube amp can you buy for $400? :cool:

Regards,
Gordon.

Not a lot of tube amp for 400 if you like tube amps. but you can buy a pair of new balanced mono block tube preamps for 100 and a really used nice balanced pro amp for 300. giving you 200 watts per channel, with tube monoblock pre input.

[Jeff B.]

You can't have high efficiency, bass extension, and small size.

If you want high efficiency and small size, you need to sacrifice low end extension.


Right. There's always a compromise, and it's interesting how simple variances in these three areas can results in some vastly different types of speakers. When I was asked to design a "high end" high efficiency speaker we had to address how we would balance these three things. First, we wanted bass at least into the mid 30's, second we wanted sensitivity of 93 dB or higher, and the higher the better, and third, the enclosure couldn't be excessively large because we had to ship this thing and people had to be able to live with it in their room. If it is too large then no one will buy it. Marketing works with the same balance as well.

Finding the right woofer was tough, but the one that made it possible for us to meet all of our goals, and do so in spades, was the Lambda TD12H, which I have written about before. This is an absolutely fabulous woofer in many respects, and capable of excellent midrange as well as good bass. Although, I wouldn't ask a 12" driver to carry too much midange. We originally used a JBL that has bit of a cult following, but the Lambda is a better driver - hands down.

The speaker shown below is the current version of the speaker you heard in Richmond, Indiana in 2008. It has a -3dB point of 36Hz and -6dB near 30Hz. It is a solid 94dB/2.83V sensitivity, and it does it in a very reasonbly sized enclosure of about 1.5 cu ft, as you can see from the pics.

http://i109.photobucket.com/albums/n70/jeffbagby/OB-tineo.jpg
http://i109.photobucket.com/albums/n70/jeffbagby/OB-tineo-2.jpg

My point is that it doesn't have to be a real big speaker to meet these goals. You heard it - you know how the bass sounds, and Dan N. liked it enough he used the woofer in his own speaker too. If you have to have higher sensitivity then the speaker will become much larger or the bass will be less extended, or both. It is all about balancing these three sides of the Iron Law.

After the woofer, there are any number of midranges and tweeters that can work in this arrangement ( and it doesn't need to be open baffle like mine). I even have a pair of B&C mids that I would sell cheap too...

http://i109.photobucket.com/albums/n70/jeffbagby/100_2300.jpg

[blair]

Snicker:D

I had a little inside bet with myself about how long this would stay on topic before the glass/sand comments came out.

Anyway, I appreciate all of your suggestions. Here is the deal. I am not looking to replace my reference system at all. I have two huge tube monoblocks, and am building a pair of 300w SS monoblocks right now. If I wanted to, I could tri-amp my system and have a total of around 300wpc of tube amps, but that is not the goal.

As a hobby, I enjoy to build small tube amplifiers. I also sell them occasionally, thus the need for a demo speaker for these. They are around 12w amplifiers typically, and yes they work on 90db speakers fine for me. Most people interested in hearing a demo though want to hear the amp on something like what they have. Typically a single driver speaker like Lowther, Fostex, Audio Nirvana, etc.... I was just curious about the AN drivers, and seeing if anyone had any reasonable suggestions that will not take up my entire house.

I also agree with Jeff B. that you do not always have to have a monster pair of speakers to get decent SPL levels. I have built several three way speakers rated at 90 or above with typical drivers. Not 94db (showoff!!)

I'm going to send you a PM Jeff against my will regarding those B & C midranges.

I'm open to continued suggestions assuming everyone understsands that this is not a tube vs. SS comparison. A well built amplifier is just that whether it is tube or SS. Period. Yep, they sound a little different, but sometimes I pick up a snicker and sometimes it is a milky way. I just change the speaker cables and listen to music.

Thanks everyone!!

Blair

[MSaturn]

A 2.5 way with SB15s yields efficiency of 89-90dB, with ungodly low distortion (and it's only $200 for four of them!) Also pretty decent bass in about a half a cubic foot enclosure - but it still has to be tall enough to get the listening axis to ear level, naturally.

You can use pretty much any tweeter you want, so long as it can cross at 2Khz LR4 or so.

Also, I'm not on either side for the tube vs. SS thing, because I've enjoyed both. HOWEVER, tubes cause remortgaging. From a practical perspective, I just can't recommend it past novelty.

[Max_Andrews]

If you want something to play with, you can build the PA130 MTM with the dayton ND20FA tweeter. Cost's about $120 for a pair for all parts, sounds good - better than most single driver systems I have heard (much better treble clarity thanks to dedicated tweeter). you can get pretty surprising bass with a larger cabinet. 1.25CF tuned to ~50hz vented gives you a slightly peaky yet full sounding EBS type tuning. Solid coverage down to 40hz. Oh and 93dB sensitivity, 4-ohm load, and this is including 3dB of BSC. It could also likely be done as a TL, but I'm no good at those :)

The design could be re-worked slightly as a 2.5-way, which would offer a better radiation pattern than the MTM.

Here's the crossover, the only thing that's not on here is that you want to add a 10ohm, 5W resistor in series with the 0.68uf capacitor.
http://homepages.nyu.edu/~msa286/pa130mtm3.gif

Here's the layout and dimensions, the only critical one is the width, you can vary the height and depth to get the cabinet volume you want. This would be nice as a small floorstander, perhaps MLTL if someone is up for that, but plain ole' ported works just fine.

http://imgur.com/onmFA.jpg

Here's the parts list (minus the 10ohm, 5W resistor). Total for everything is just under $120:
http://imgur.com/bbUwA.gif

[MSaturn]

Note that making that design a floorstander will dramatically change baffle step response and that 3dB of BSC will lose its efficacy.

[benchtester]

Snicker:D
As a hobby, I enjoy to build small tube amplifiers. ... They are around 12w amplifiers typically...

Just for my edification:
Are your amps okay with 4 ohm speakers? In general, are small tube amps okay with 4 ohms assuming fairly flat impedance?

[Max_Andrews]

Well it's still a really skinny floorstander, so there would still need to be some baffle step unless it's placed close to the walls. The response already droops a bit in the midbass range, so I'd think the main change by going floorstander would just fill out the midbass more, which is a good thing. I have all the parts for this, so this weekend i'll try to toss together a floorstanding box and give it an audition, and see if any crossover tweaks are needed as a result.

I'm thinking a final box size of 6.5" wide by 40" tall by 11.5" deep external, using well braced 1/2" material and a 1.25" thick baffle would do nicely.

[dlneubec]

You might consider by BaSSlines design, which was inspired by Jeff Bagby and Jim Salks design posted above. It uses the AE Lamba TD12H, the B&C 6md38 mid and the Peerless HDS tweeter in a shallow waveguide. They are 16" wide at the base, 7" wide at the top and 42" high, a pretty small package. The lexan baffle makes them appear even smaller than the dimensions indicate. More info is available at the links below:

http://i32.photobucket.com/albums/d44/dlneubec/BaSSlines/DSCF0250.jpg

http://techtalk.parts-express.com/album.php?albumid=97

http://techtalk.parts-express.com/showthread.php?p=1518334#poststop

[Jeff B.]

Snicker:D

I had a little inside bet with myself about how long this would stay on topic before the glass/sand comments came out.

Anyway, I appreciate all of your suggestions. Here is the deal. I am not looking to replace my reference system at all. I have two huge tube monoblocks, and am building a pair of 300w SS monoblocks right now. If I wanted to, I could tri-amp my system and have a total of around 300wpc of tube amps, but that is not the goal.

As a hobby, I enjoy to build small tube amplifiers. I also sell them occasionally, thus the need for a demo speaker for these. They are around 12w amplifiers typically, and yes they work on 90db speakers fine for me. Most people interested in hearing a demo though want to hear the amp on something like what they have. Typically a single driver speaker like Lowther, Fostex, Audio Nirvana, etc.... I was just curious about the AN drivers, and seeing if anyone had any reasonable suggestions that will not take up my entire house.

I also agree with Jeff B. that you do not always have to have a monster pair of speakers to get decent SPL levels. I have built several three way speakers rated at 90 or above with typical drivers. Not 94db (showoff!!)

I'm going to send you a PM Jeff against my will regarding those B & C midranges.

I'm open to continued suggestions assuming everyone understsands that this is not a tube vs. SS comparison. A well built amplifier is just that whether it is tube or SS. Period. Yep, they sound a little different, but sometimes I pick up a snicker and sometimes it is a milky way. I just change the speaker cables and listen to music.

Thanks everyone!!

Blair

Regarding the B&C mids - here is the post on them in the classifieds which gives you more complete info on them:

http://techtalk.parts-express.com/showthread.php?t=211467

The price is very negotiable - would even consider trading stuff if someone is interested. It's just that I probably won't get around to ever using them, so I thought I would see if someone else might find them appealing.

Jeff

[blair]

Just for my edification:
Are your amps okay with 4 ohm speakers? In general, are small tube amps okay with 4 ohms assuming fairly flat impedance?

Yes, I have used them with 4 ohm speakers with no issues.

Blair

[blair]

You might consider by BaSSlines design, which was inspired by Jeff Bagby and Jim Salks design posted above. It uses the AE Lamba TD12H, the B&C 6md38 mid and the Peerless HDS tweeter in a shallow waveguide. They are 16" wide at the base, 7" wide at the top and 42" high, a pretty small package. The lexan baffle makes them appear even smaller than the dimensions indicate. More info is available at the links below:

http://i32.photobucket.com/albums/d44/dlneubec/BaSSlines/DSCF0250.jpg

http://techtalk.parts-express.com/album.php?albumid=97

http://techtalk.parts-express.com/showthread.php?p=1518334#poststop

Thanks Dan,

Actually my unfinished speakers are similar, but not that efficient.

The Ushere 8848P here is open baffle and the tweeter is the HDS like yours. I'm just slower than you at building my designs.

Blair

[WmAx]

Looks like everyone is trying for a high efficiency design these days. I guess this is the 'flavor of the year'? Heck, even I'm going to go for one (with about 97-98db/1 watt efficiency target range), though I do want it to operate with the same performance/fidelity as the finest home speaker systems. But I am having a bit of difficult time figuring out what drivers to use, or even pick out to buy to test - this is a new area to me.
-Chris

[MSaturn]

Man, those things look CRAZY. I love it.