Wading through the theory...
Thanks scott for steering me to the MJK theory sheets...
Martin goes through a discussion of "compromised horn/transmission line" geometries - geometries that just aren't big enough!, and says (among other things)
And I see from the 6moons review that for the second Firsthorn we're basically talking about a "choker plate" on the end of the horn. That was pretty much what I was thinking about at the start; now I just know that it's really a double-bass reflex expanding line mass-loaded transmission line
not a horn anymore.
Just got Martin's sheets - time to play. And this has given me the motivation to start digging into horns. Which could be a problem, I think they're cool, the wife likes teeny-tiny speakers. Black ones.
Still don't believe that bass from a fe108es, but I'm prepared to be astonished.
Thanks scott for steering me to the MJK theory sheets...
Martin goes through a discussion of "compromised horn/transmission line" geometries - geometries that just aren't big enough!, and says (among other things)
And I see from the 6moons review that for the second Firsthorn we're basically talking about a "choker plate" on the end of the horn. That was pretty much what I was thinking about at the start; now I just know that it's really a double-bass reflex expanding line mass-loaded transmission line
not a horn anymore.Just got Martin's sheets - time to play. And this has given me the motivation to start digging into horns. Which could be a problem, I think they're cool, the wife likes teeny-tiny speakers. Black ones.
Still don't believe that bass from a fe108es, but I'm prepared to be astonished.
You are correct, sir.
My oversight.
Actually -- the TOP closely resembles the 6th order bandpass series
Both have one exit port only.
The cannon resembles the 6th order bandpass.
Both have two exit ports
Getting back on topic (mass loaded horn)...
I believe what they are doing is building a BLH.
They cover the horn mouth with a panel.
They add a port that tunes it to 20hz.
Take a look at the 6Moons review of their "First Horn" (2nd review).
To that extent it is similar to TD's TOP.
It is an expanding TQWP with an undersized mouth.
In this case it is WAY undersized -- hence 20hz tuning.
No "black hole" here.
This could definitely be modelled in MJK...
My question is "does SQ suffer?"
Read the 6Moons review...
(edit: I just noticed Cheesehead said essentially the same thing -- sorry Cheesehead)
My oversight.
Actually -- the TOP closely resembles the 6th order bandpass series
Both have one exit port only.
The cannon resembles the 6th order bandpass.
Both have two exit ports
Getting back on topic (mass loaded horn)...
I believe what they are doing is building a BLH.
They cover the horn mouth with a panel.
They add a port that tunes it to 20hz.
Take a look at the 6Moons review of their "First Horn" (2nd review).
To that extent it is similar to TD's TOP.
It is an expanding TQWP with an undersized mouth.
In this case it is WAY undersized -- hence 20hz tuning.
No "black hole" here.
This could definitely be modelled in MJK...
My question is "does SQ suffer?"
Read the 6Moons review...
(edit: I just noticed Cheesehead said essentially the same thing -- sorry Cheesehead)
Greets!
Duh....... Fostex syle horns are just a bunch of resonant tubes driving each other Vs a real horn's continuous expansion, so there's efficiency losses with the trade-off that it somewhat limits higher frequencies from exiting the mouth. One can argue that overall, this is a worthwhile trade-off, but then the horn needs to be bigger to get the efficiency back. Not many 'free lunches' in audio.
GM
Duh....... Fostex syle horns are just a bunch of resonant tubes driving each other Vs a real horn's continuous expansion, so there's efficiency losses with the trade-off that it somewhat limits higher frequencies from exiting the mouth. One can argue that overall, this is a worthwhile trade-off, but then the horn needs to be bigger to get the efficiency back. Not many 'free lunches' in audio.
GM
GM said:
Hi GM,
Yes I remember you stating that before wrt Nagaoka blh and its clones. That's why I mentioned they are 'different in operation'. Anyways, my question is about the 'True Horn' with smooth bends GemmeAudio uses in the CNC'd baffles. Is there any real advantage/sonic gains to it vs. the common sharp bends in horns?
Greets!
I guess I wasn't clear enough, a proper horn will have more gain and BW for a given bulk and a smoother response. Whether it's worth the extra effort will depend on the app and the individual it has to please. For LF/lower mids in a HIFI multi-way, probably not, but for prosound it will since they want all the gain BW they can squeeze out of a given bulk, while for a wide BW HIFI app it will for some.
GM
I guess I wasn't clear enough, a proper horn will have more gain and BW for a given bulk and a smoother response. Whether it's worth the extra effort will depend on the app and the individual it has to please. For LF/lower mids in a HIFI multi-way, probably not, but for prosound it will since they want all the gain BW they can squeeze out of a given bulk, while for a wide BW HIFI app it will for some.
GM
qi said:
Greets!
I believe that I am to the folks who are interested enough in what I have to say.
So I'm told on occasion, but my attitude is if you don't like it, don't read it. This is my hobby, so I'm primarily interested in 'bench racing' it or helping like-minded folks who are interested enough to learn the lingo.
Except for a few 'proofs-of-concept' cobbled together to help others, a pair of MLTLs for a friend around the same time (all documented on the old FR forum), and some stuff for me that I've since sold to help support the greedy medical community, nothing much in the past decade I've been on-line. Not that it matters at all, of course.
Speaking of building, what have you built/shared with us lately, or at all for that matter? I don't recall ever reading about one. I at least publish designs on a regular basis that others build/claim to enjoy. Indeed, you've even recommended some of them.
GM
GM said:
And thanks to you for the plans. The dimension is 42" internal (I just got up and measured, it's been about a year.) I finished them when my brother-in-law was visiting - although I'm used to them, he still just sits in awe of them when he visits.
My next goal is to get a measuring setup working so I'm not flying blind (deaf?).
I've built exactly three sets of speakers so far, two if I don't count the subs... but I'm one who has to read, model, read, plan, replan
Just haven't decided if I do my work electronically (with a crossover) or in a shop (building a complex enclosure)!
cheesehead said:
Greets!
You're welcome!
OK, you chose a length in-between the short and tall versions, so I'm curious what vent size/length you used. Or did you build the 31" version with the vent extending out the bottom?
I did the complex woodworking thing when I was young, but as the electronics advanced to the point where I could 'cut corners', so to speak, I did to save time since by then I had a family, etc.. For all out performance though, it takes both these days.
GM
GM said:
Hi GM,
You were very clear. I understand what you are saying wrt proper horn's expansion = higher gain and BW... Nagaoka was actually besides the point (different by having Right Angled bends and such), I only cited it coz it also had sharp bends. I think the way I posted my orignal query wasn't really clear. Coming from another country my (english) syntax takes on another meaning most often than not
. Sorry about that.My question was really in reference to the the zine review that Dave Panet10 posted some pages back:
*taken from review*
http://www.6moons.com/audioreviews/gemmeaudio/108_2.html
GemmeAudio touts its enclosure for having NO sharp bends. So I was thinking if sharp bends really affect performance even if the horn is properly designed with folds having proper expansion etc.
Anyways, just a while ago I remember reading a post of yours in the BiB thread, busting the myth that sharp bends/points are a bad idea:
http://www.diyaudio.com/forums/showthread.php?postid=894001#post894001
http://www.diyaudio.com/forums/showthread.php?postid=893467#post893467
I guess that somewhat sheds some light on my orignal question. A smooth CNC'd horn path really looks neat though. Thank you.
regards,
fred
Guys... GM is one of the few people I know here who has both the practical experience in building speaker enclosures (big @ss ones at that) and have solid know-how to back up the results. He is also one of the few people here who you can really learn from from a practical point of view. And his insta-enclosure by the numbers is really cool IMO once you get past the geewhiz arcane “speakerdesignspeak” (hehe) and build it. There are a few people here I could count who shares specific enclosure designs freely and offers sincere advice. He is one of the good guys.
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