• Response chart, excursion plot and impedance chart of a specific driver mounted on an infinite baffle
  
• Response charts of said driver in specific back loaded horns, reflex cabinets and transmission lines
  
• Driver excursion plots of same driver in specific back loaded horns, reflex cabinets and transmission lines
  
• Impedance plots of same driver in specific back loaded horns, reflex cabinets and transmission lines

What started the thread was the simple premise..." Why won't a single driver speaker do metal?" I completely disagree with the premise and my only intention was to simply give one type of design that demonstrates this is simply not so. As I stated before......In my EXPERIENCE I have not heard a sealed (without a sub) or a TL (without a sub) pull it off. So to a point I agree. But that's only to a point.....I know for a fact that a BLH can do it. The only hard numbers I can offer (at this time) is the testimony from Larry .........If some of you doubt that he or I know what "audible distortion" is or that we don't know what "bass" should sound like (he is a musician, and should "have a clue"), or that 106 dB @ 15 feet is not "loud enough" to qualify as "doing it", well, I can't help it.

I am sorry that I can't give a detailed comparison of the designs in question but that was not the original premise anyway. It was the inability of a single driver to play a certain type of music. And that is just wrong.......

I linked to the J-Low article because it does have a little bit about what we were going on about. I think in the article Nelson says something to the effect that they built the J-Low because no other enclosure would have the efficiency gains he wanted. And they did in fact build a couple non-BLH boxes. Page 2 of the article says pretty much exactly what I have been saying.........the excursion in the bass severely limited SPL. And so they built a BLH. It is right there and a real example.

Anyway.............I never said the other designs don't "sound good" within their limits. But again the only single driver speakers that I have heard that go loud enough (for me at least) have all been BLHs. That's my story and I'm sticking with it! I won't present any more "examples".....I think the Pass article says enough about it. If that does not help the prospective "single driver builder" then I'm sorry....it's all I got!

This has been a rather nice discussion.....and it ain't a rule we agree on everything!

Ed

I might add....a person could make the numbers go any way they want by simply building a non-optimum enclosure. In order for the results to be accurate the 3 examples would have to all be the optimum enclosure and the drivers would have to be the same size and since the parameters for the optimum driver for each design are so wildly different a fellow could get any result he wanted. And besides all that, I thought Mr Klipsch settled the efficiency of a horn vs. everything else 50 years ago!

A backloaded horn doesn't increase efficiency through most of the passband. It only increases output at low frequencies, to augment where the driver is getting weak. So it doesn't help efficiency.

The reason I've suggested comparing the horn and the transmission line is that I believe that they are more alike than different. When used at bass frequencies, a horn has to be pretty large. When it is made small, it is really a tuned pipe.

Cornerhorns are small tuned pipes that use the corner as the mouth. The physical construction of a small backhorn is very similar to that of a transmission line. They act pretty much the same. Put a transmission line in the corner, and it acts very much like a backhorn placed in the corner. Alternately, take a backhorn out of the corner, and it becomes a tuned pipe.

I think it is productive to look at these things, even if just done in models. That will show you what I say is true. You know how I know? Because I've done it.

• Basshorn or Transmission Line

I do own the BB FTA-2000s and enjoy them immensely. I enjoy different single driver implementations..so I look forward to hearing your models. I find some of the Cain models to be nice sounding and beautiful to look at..but IMHO a bit overpriced.

I'm just glad there are fellows like you and Mr.Brines that make world class sounding speakers and real world prices.

Have a great weekend or what's left of it!

"Here's the thing, Ed. It isn't fair for you to pounce on Bob's statement, "Single-driver full-range speakers have a limited dynamic range." That was a statement of fact, and you shouldn't use it to launch a campaign. It isn't a statement about horns or transmission lines, it is a statement about single drivers. "

Sorry, didn't mean to start anything. But I might ask the question...limited dynamic range by what standard? Compared to a K-horn? Or compared to similar sized drivers? I have not really noticed "limited dynamic range" to be a problem (when horn loading them). I would assume that my 4 Klipsch La Scalas had adequate dynamic range. Thing is, that at sane levels, they didn't sound any more "dynamic" than the little single driver that replaced them. And that is exactly why they were replaced! Again, I thought the premise was...."Why a single driver can't play metal". I stand by my position. They can. In some cases and loadings.

" It only increases output at low frequencies, to augment where the driver is getting weak. So it doesn't help efficiency"

That IS an increase in efficiency.....it is just at the bottom where it is needed.

"When used at bass frequencies, a horn has to be pretty large. "

Yes they do, I agree which is why in my favorite example it is actually meant to be used in corners for that very reason.

"The physical construction of a small back horn is very similar to that of a transmission line. "

Not really, Maybe some........in my example there is a compression chamber, a throat, and the path is an exponential flare and when in corners the mouth is just about right for the intended cutoff. It is not similar to any TL I have seen. It may "behave" that way when not in the corners but I am not even sure that is right.

"Put a transmission line in the corner, and it acts very much like a back horn placed in the corner. Alternately, take a backhorn out of the corner, and it becomes a tuned pipe. "

Now, this I have to think about! The TLs I have had experience with simply went "boomy" when placed in corners and the BLH had the cut off raised. So I'm not sure if they are "flip flopping" in the way they behave.....we both know any speaker in a corner will gain a little efficiency. A TL that was not designed for a corner will have a big bump in the LF response that it simply does not need. Boom.

"That will show you what I say is true. You know how I know? Because I've done it."

I believe you, based on your examples.

It should be noted that in my comments I was referring to a TRUE BLH.....one that either has a proper mouth or uses the corners to "fake it".
It also has a "real" compression chamber....a "real" throat....and a genuine exponential flare on a length that is correct for the cutoff. I have not been talking of a hybrid. But rather a "true" horn. In my example that would in fact be a "Back Loaded Corner Horn"

I think we agree there is a place where the designs overlap.....but that is not what I have been talking about. I have meant all along a "true" BLH....one with a mouth the right size and if it is vented to the front and not designed to use the corners it will be big like the J-Low.....or you could use the corners and then the walls form the "big" mouth.

Boy, this is a touchy subject! The fact that Jeff "outed me" may lead some to think I have some sort of agenda.....nothing could be farther from the truth. I wish that had not happened....it clouds things and may lead guys to a wrong conclusion about why I'm posting my OPINIONS. I was simply trying to encourage guys who might have been thinking about building a single driver speaker to continue on and not be discouraged by the OPINION they can't play "Metal". That is all.

Ed

The thing is, average SPL is not increased whether using a backhorn, transmission line or reflex cabinet. They all boost bass output only. So all of these types of loudspeakers have basically the same maximum SPL limit.

I'd like to kerf-bend one up, all smooth curves and flow.  Only thing, where in my little cottage would I put 'em;?  I'd have to listen through the doorway from the next room!

Nelson and Dana are hero designers to me; they really know how to make extreme projects elegant and constructable.  Boy, would I like to build a pair of these, suitably poinzified.

P.

Dave

Hand her the whip.  Stick out your tongue, 'BLEAH!'

Don't forget to take off your pants first.

Do not report back, by all means.

P.