BVR vs Pensil - pros and cons ?

[rjbond3rd]

This:

Understanding the Replikon horn

[planet10]

Originally Posted by Bigun

What am I missing here ?

Have you read the Spawn intro on the FH site? That will point you to other (explicit) BVRs? Many small horns, for that matter, a daline, are BVRs.

dave

[planet10]

I see Robert beat me to one of those links...

dave

[GM]

Originally Posted by Bigun

For the horn-loaded reflex I'm not so sure I understand how it works as there's little published literature that I've seen. I'm wondering if the horn loading provides a similar benefit in widening the resonance of the reflex, providing a broader range of driver loading without the ripple that has to be damped on an MLTL ?

There’s a good size library of published literature in speaker, TL, horn design theory dating back to at least the 1920s, though never seen any for MLTLs per se since apparently Olson didn’t see his late ‘40s vented tower/column speaker as sufficiently different enough from a pure reflex to justify patenting it. Then there’s his and others technical books on acoustical loading as well as musical instrument design and the plethora of professional technical papers from dozens of authors over the ensuing decades.

Regardless, you seem to understand BVR/BLH loading at its ‘fundamental’ .

GM

[Bigun]

Originally Posted by rjbond3rd

This:

Understanding the Replikon horn

thanks ! - this was a very useful thread. Just gets me more interested in the BVR approach and the possibility of designing one to the outer dimensions of the totem arro based on an EL-70 or CHR-70 driver. I will give this further thought!

[planet10]

Originally Posted by Bigun

thanks ! - this was a very useful thread.

Note that that like (and others) have been in the Spawn section of frugal-horn.com (home of Scott's BR) for 4 years...

dave

[Bigun]

I guess it's a case of better late than never.

There are so many different names and so many different speaker designs that for most part I have not been able to 'see the wood for the trees'. I found the same with amplifier design, fancy names for all the different circuits - cascodes, cascades, White followers, capacitance multipliers etc. and it was quite awhile before I could see the whole picture and the connections between them all.

I'm seeing that you can't categorize speakers along clear lines either, it's all a spectrum. Take the FH3, is it a horn, or is it a BVTL (big vent transmission line) or is it both and something else besides !

Actually now that I think of it, perhaps the FH3 is easier to scale since it's mostly a TL and all I need to do is keep the CSA and length the same... hmmm, a little knowledge is a dangerous thing

And now that I think about what I'd like in terms of form factor (totem arro) it's not clear that it will behave as a reflex enclosure when so long and thin, it's bit between a TL and a BR. Can one add a big vent to a Pensil ?

[GM]

Originally Posted by Bigun

Actually now that I think of it, perhaps the FH3 is easier to scale since it's mostly a TL and all I need to do is keep the CSA and length the same... hmmm, a little knowledge is a dangerous thing

Oh really?! Indeed!

GM

[Bigun]

well, perhaps not easy.....

[GM]

Scaling is actually easy once you understand the physics of the situation, but unless you have the math skills to work it out long hand or have a fairly unique way of looking at such things, it's not intuitive.

Trust me, I know, as scaling horn pictures using a Pantograph in my teenie-bopper years and loading them with a variety of used tabletop radio, TV, etc., drivers is how I got started and as you can imagine, I got some rather strange sounding speakers that had just about convinced me to give up on such 'flights of fantasy' as my mom called them when one day I lucked up big time! I happened to find an oval driver that sounded good enough in one of my largest scaled horn cabs [Altec 211, I learned several years later] once stuck in a corner that it became the rage within my 'circle of influence', with a number of copies made, 'hooking' me on this hobby.

Of course I had no clue how to reverse engineer it, much less scale it, that was still ~ a decade away before I'd accumulated enough knowledge since I couldn't do the math in the textbooks loaned from the Ga. Tech library.

Now that I know approximately what its driver specs was and that it still lives on as a staple of car audio, I've considered building another one to see how bad it really was referenced to 'FR' driver HIFI as we know it today. Since all we had available were various AM radios to drive them, I'm guessing the ~flat source BW was limited to ~ a phone's ~250-2500 Hz BW, so anything but 'full-range'.

GM