The obvious drawback is that the FLH and BLH efficiencies are fighting each other. For every bit of FLH efficiency, you need even more gain from the BLH.
I could imagine a very, very short FLH might be able to be shoe-horned into a total solution, to provide a tiny bit of efficiency at a strategic place in the FR, but that's just a guess.
This is the sort of problem well-suited to a supercomputer -- churn through a trillion possibilities to see if a solution exists, or see what solutions are possible given a set of inputs. Supercomputing opens up a whole new set of possibilities.
Maybe someday you'll stick a driver into a microwave, and a supercomputer will calculate the appropriate compound horn, CNC it from artificial Baltic Birch ply, and beam it to your hovercar. Who know?!
I will confess that even as a total newb, I have puzzled over a BR/FLH combo for the FE207E, but I can't get enough gain from the BR to keep up with the FLH, unless the FLH is only there for BSC, and that's no fun. :0
I could imagine a very, very short FLH might be able to be shoe-horned into a total solution, to provide a tiny bit of efficiency at a strategic place in the FR, but that's just a guess.
This is the sort of problem well-suited to a supercomputer -- churn through a trillion possibilities to see if a solution exists, or see what solutions are possible given a set of inputs. Supercomputing opens up a whole new set of possibilities.
Maybe someday you'll stick a driver into a microwave, and a supercomputer will calculate the appropriate compound horn, CNC it from artificial Baltic Birch ply, and beam it to your hovercar. Who know?!
I will confess that even as a total newb, I have puzzled over a BR/FLH combo for the FE207E, but I can't get enough gain from the BR to keep up with the FLH, unless the FLH is only there for BSC, and that's no fun. :0
I think you might be looking at compound horns (& BLHs in a way) from the wrong angle here. This isn't universal by any means, but FWIW...
Ideally, drivers for a BLH should have a low[ish] mass corner (i.e. the opposite of what is often used in them) -that way you can run the horn up & compensate for their LF roll-off, right? Simplistic, and it's ignoring other issues in the FR, such as the peaking many units exhibit in the upper mid-band. For sake of example, SPLs on the FE206E start to increase over ~1.2KHz, to a plateau roughly 7db over nominal. That's in a sense where a compound horn can come in. You use the bass horn on the back to boost the LF above the nominal (preferably to ~the same maximum efficiency / sensitivity of the driver), up to the driver's mass-corner, or whatever upper-corner-frequency you happen to have selected. You then bring in the short front horn from that point to lift everything above that again, up to the point where the plateau begins & then roll it off. So everything avereages itself out. See the (very) crude attached -blue = bass horn, red = midrange horn.
That's one method anyway (there are plenty of others of course & I'm being deliberately crude here). The 207 theoretically wouldn't benefit much from it, as it is already possesses a reasonably flat response, ergo it doesn't really need much help above it's mass-corner for the FR to remain balanced.
Ideally, drivers for a BLH should have a low[ish] mass corner (i.e. the opposite of what is often used in them) -that way you can run the horn up & compensate for their LF roll-off, right? Simplistic, and it's ignoring other issues in the FR, such as the peaking many units exhibit in the upper mid-band. For sake of example, SPLs on the FE206E start to increase over ~1.2KHz, to a plateau roughly 7db over nominal. That's in a sense where a compound horn can come in. You use the bass horn on the back to boost the LF above the nominal (preferably to ~the same maximum efficiency / sensitivity of the driver), up to the driver's mass-corner, or whatever upper-corner-frequency you happen to have selected. You then bring in the short front horn from that point to lift everything above that again, up to the point where the plateau begins & then roll it off. So everything avereages itself out. See the (very) crude attached -blue = bass horn, red = midrange horn.
That's one method anyway (there are plenty of others of course & I'm being deliberately crude here). The 207 theoretically wouldn't benefit much from it, as it is already possesses a reasonably flat response, ergo it doesn't really need much help above it's mass-corner for the FR to remain balanced.
Attachments
where does the "no-box" approach with typical 150Hz-up use of 206 and 15 or 18" open baffle helper woofer put the builder/listener versus good BLH? - did the 2-way OB lose "oneness"? are good BLH completely seamless in most situations? (I thought I heard "lag" in BK20) how about modulation effects? OB might not like being placed near back walls - are the baffle/helper brigade forced to use more powerful amps? (or biamp if SET are desired for most of the vocal range)
I guess any more discussion is purely academic, as wood's already cut.
--and cut for what was stated in the first post "most want to have, the Sachiko;" so the whole thread may well be academic...
So the builder wins!!!
He gets what he wants!!!
And everyone else gets to talk & pipe dream & what if...
Anyway, just for discussion's sake, RCA-:Fans have had good reviews on other forums. I know of one person who had Decware HDTs he had listened to quite some time, built the Karlson slot cabs & preferred them.
And @ the last listening party, several of us liked the HDTs better than the double mouth BVR "horns."
And Ron's Dallas BLH didn't come up, but would be a likely candidate if one wanted to stick with a BLH...
I'll stick w/ front loaded horns.
I just think they sound better, besides being more efficient, and allowing better sounding amps.
(see if that re-opens a can of worms)
--and cut for what was stated in the first post "most want to have, the Sachiko;" so the whole thread may well be academic...
So the builder wins!!!
He gets what he wants!!!
And everyone else gets to talk & pipe dream & what if...
Anyway, just for discussion's sake, RCA-:Fans have had good reviews on other forums. I know of one person who had Decware HDTs he had listened to quite some time, built the Karlson slot cabs & preferred them.
And @ the last listening party, several of us liked the HDTs better than the double mouth BVR "horns."
And Ron's Dallas BLH didn't come up, but would be a likely candidate if one wanted to stick with a BLH...
I'll stick w/ front loaded horns.
I just think they sound better, besides being more efficient, and allowing better sounding amps.
(see if that re-opens a can of worms)
No, but on that basis, I better scrap all my designs (I'm sure Horst will be delighted). That said, I gather you didn't hear particularly good examples of them...
The NFX is an interesting take on the trad BR / transflex theme with that massive vent system. I don't know the exact dimensions of course, but I make it as being tuned to roughly 70Hz, peaking somewhat, with an F10 around 50Hz.
The NFX is an interesting take on the trad BR / transflex theme with that massive vent system. I don't know the exact dimensions of course, but I make it as being tuned to roughly 70Hz, peaking somewhat, with an F10 around 50Hz.
n_martin said:
backload horn tried as compound horn:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=126132
http://www.audiovoice-acoustics.com/forum/showthread.php?t=225
200-15000hz might be stretching it...
I discussed this ("fulrange" driver instead of compression driver in front load horn) with Bert Doppenberg @ RMAF, he said the best he's heard/done is using a 250Hz horn w/ 6" driver.
The horn is an acoustic low-pas filter though, and it needs a tweeter.
lynx:
As mentioned before, Martin Seddon Azurahorn http://www.azurahorn.com/
Or Oris/Swing -- Bert Doppenberg http://www.bd-design.nl/ (lotsa links, designs, forum)
both make horns in that range, but you may want a tweeter crossed lower than that.
or http://www.goodsoundclub.com (lotsa horn info if you dig).
or if you want something custom built that will really work, email Jeffery Jackson, but his web site is presently down.
Hi guys,
Scott thank you for the chart -- that does help a great deal. This design stuff is proving really difficult to crack. I'm not suited to the design stuff (nor the building, nor the varnishing) but I keep trying anyway. Sad, really.
My impulse was to use the FLH to control directivity (to keep reflections off the walls). I noticed that these little Klipsch Heresies in my room seem to have less reflections off the side walls (is that possible? It seems to be the case anyway). Thank you for the explanation and the overlay, Scott!
Hi Robert, I laughed out loud when I read Scott's words as well, because I also thought he meant we didn't hear good FLH's. But I believe he means we did not hear good examples of his (Scott's) designs. (In my mind, we did hear a good example in the form of Phil's Harvey's.)
OT but my wife is still positively traumatized at seeing the Altec A7's in Monte Verdi's living room:
http://groups.google.com/group/sfaudio/web/sfas-gathering-2-7-09
Serenechaos/Robert, your 5-way horns will make Monte Verdi's Altecs seem very compact.
Scott thank you for the chart -- that does help a great deal. This design stuff is proving really difficult to crack. I'm not suited to the design stuff (nor the building, nor the varnishing) but I keep trying anyway. Sad, really.
My impulse was to use the FLH to control directivity (to keep reflections off the walls). I noticed that these little Klipsch Heresies in my room seem to have less reflections off the side walls (is that possible? It seems to be the case anyway). Thank you for the explanation and the overlay, Scott!
Hi Robert, I laughed out loud when I read Scott's words as well, because I also thought he meant we didn't hear good FLH's. But I believe he means we did not hear good examples of his (Scott's) designs. (In my mind, we did hear a good example in the form of Phil's Harvey's.)
OT but my wife is still positively traumatized at seeing the Altec A7's in Monte Verdi's living room:
http://groups.google.com/group/sfaudio/web/sfas-gathering-2-7-09
Serenechaos/Robert, your 5-way horns will make Monte Verdi's Altecs seem very compact.
rjbond3rd/Robert,
yeah, I thought Phil's Harvey's were very well built examples good examples too...
maybe he I]did[/I] mean we didn't hear any good FLHs...
We didn't...
All I had were some kludged together jbls, radians, gotos & home made jobs, nothing finalized, and "right."
But still good enough to hear the difference...
Yeah, FLHs do control directivity, as well as raise efficiency.
Ha! If a little pair of A7s traumatized your wife, you'll have to bring her over when I get the five-way up...
should look something like this:
http://www.theanalogdept.com/images/spp6_pics/VSAC08/GOTO_08_1.jpg
except with 304TL tube amp...
Then anything you build will look small!
yeah, I thought Phil's Harvey's were very well built examples good examples too...
maybe he I]did[/I] mean we didn't hear any good FLHs...
We didn't...
All I had were some kludged together jbls, radians, gotos & home made jobs, nothing finalized, and "right."
But still good enough to hear the difference...
Yeah, FLHs do control directivity, as well as raise efficiency.
Ha! If a little pair of A7s traumatized your wife, you'll have to bring her over when I get the five-way up...
should look something like this:
http://www.theanalogdept.com/images/spp6_pics/VSAC08/GOTO_08_1.jpg
except with 304TL tube amp...
Then anything you build will look small!
Scottmoose said:You might even find you won't feel the inclination after you've heard Sachiko judging from the reaction of a lot of Sachiko's builders.
I was planning on thanking you for the wonderful design, but it sounds like you're already patting yourself on the back! I don't think a speaker project is next in the cue to be honest - people close to me are going to have an intervention if I build any more right now...
rcdaniel said:
Well, the reasoning behind these thoughts is this; I love the way FLH look, and as a designer, with fairly sophisticated 3d software, I feel like I could fabricate them in new and interesting ways. In addition, the FLH seems to offer the greatest efficiency of any design. The idea of combining it with a TL bass is probably not well thought out, but since TLs do offer deep, fast bass it seemed logical, although there are a number of problems with the whole idea.
I think I will take a few hobby xanax and just find a good amp that I can build for the Sachiko - probably a kit.
This leads me to my next question:
Can anybody recommend a small tube amp for the Sachiko / know the speaker's sensitivity? Would a Decware Zen do the job? Or do I need 5-10 watts?
n_martin said:
Yeah, the FLH does offer the greatest efficiency of any design.
You'll pick up roughly 6dB over whatever the driver would be putting out.
Which can be a problem mixing design types, as the TL isn't as "fast" (although some will argue "fast" bass doesn't exist), or as efficient.
So the horn might be padded down (not so good), system bi-amped (better), or bass horn used, with matching efficiency, with same or seperate amps.
Decware Zen--
I use a Zen Select (on rotation), it's enough power most of the time (w/ 166 BLH or 206 TL).
Good for moderate to "normal" listening levels.
For rock or symphony playing through the house, or into the shop, I use a bigger amp.
Hope that "non-answer" was of some help...
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.