I can't forget what audio is like, but I try.
just play some more of your burning down the house through your compression drivers at 100 watts maybe you'll remember
LM555. The 7V 1.5A FC supply is easy to do. I'm using a 110Ahr batteries but anything works. Make a straight 160Hz horn for it. Forget the whole WE thing, it's just a driver. Maybe a little expensive but look what hi-end speakers cost.
btw I can make 425 horns for 1" drivers now - just did a mould extension.
that will work but how well, i recently compared the tad 4001, selinium 405, gauss 4000 and community m200 in a 180 flare tractrix round horn to an altec 299 in both large keele ev hr6040 and hr9040 constant directivity - great white whale horns - 220 hz flares - with appropriate networks and none of them made it down into the low midrange like a 8-10 inch horn loaded driver- 600 hz is the break point i think for most medium or large format compression drivers and that's middle midrange not low midrange- all three horns sounded better when low passed and used with a good treble driver and horn - just my experience ymmv
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Thanks Pooh, Scott,
@ Pooh: Nearly the same for me : plenty Poon Tang Bang too but still no High efficienty speakers... It's odd the goals are changing with aging ! :
Me: "baby I'm still > 15.... K Hz !"
Wife (at very low voice) : " so, may you clean the dishes..."
Me to doggy (at very very low voice) : "hey 40 K Hz doggy: clean the dishes or I play some Madona !"
Doggy to wifey : "whouf whouf, I believe you should buy a big Tannoy for him and some new reccordings"
SOrry, My french !
@ Pooh: Nearly the same for me
: plenty Poon Tang Bang too but still no High efficienty speakers... It's odd the goals are changing with aging ! :Me: "baby I'm still > 15.... K Hz !"
Wife (at very low voice) : " so, may you clean the dishes..."
Me to doggy (at very very low voice) : "hey 40 K Hz doggy: clean the dishes or I play some Madona !"
Doggy to wifey : "whouf whouf, I believe you should buy a big Tannoy for him and some new reccordings"
SOrry, My french !
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LOL, you cracked me up! Thanks Thanks Pooh, Scott,
@ Pooh: Nearly the same for me
Me: "baby I'm still > 15.... K Hz !"
Wife (at very low voice) : " so, may you clean the dishes..."
Me to doggy (at very very low voice) : "hey 40 K Hz doggy: clean the dishes or I play some Madona !"
Doggy to wifey : "whouf whouf, I believe you should buy a big Tannoy for him and some new reccordings"
SOrry, My french !
POOH is right. The usual problem with excessive center-to-center spacing is lobing in the vertical plane ... you move around the room and hear odd swishing noises as your ears pass through acoustic nulls.
Once you get above 7~8 kHz, though, this problem goes away. It's really difficult to hear nulls, even when you use a deliberate test stimulus like pink or white noise. Go an octave lower, and it's very audible, can interfere with perception of stereo depth, and change the vocal timbre of singers. But 7 kHz or above, audibility is essentially non-existent. You can hear peaks if they're aggressive enough, but not dips in response.
POOH also makes a good point about horn bandwidth. Don't expect too much. The traditional rule-of-thumb is a bit more than three octaves, or a decade (1:10) of bandwidth. Dr. Geddes takes full advantage of his OS profile, and gets a bandwidth of 1:20 ... but his crossovers are very sophisticated and rely on advanced measurement techniques.
I am not sure why folded bass horns (like the Klipsch LaScala or similar) don't sound more objectionable than they do. By measurement, they have really ugly peaks and dips, but maybe it doesn't matter in the clutter of room modes that fall in a similar frequency range.
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Not wanting to speak on his behalf but I don't think his crossovers are the reason for this, their benefit lies in integration.
It could be that conicals are lower gain devices and hence higher bandwidth. Their acoustic loading doesn't enter as heavily into it. The band extremes tend to be more influenced by specific aspects of the horn rather than the horn as a whole.
It's called optimizing the "system".
Although I would say that no crossover can alleviate the problems of direct radiators. Constant directivity requires waveguides and good waveguides require complex (or at least unusual) crossovers.
I'm just finishing up the last speakers that I will ever make, an unusual set of NS15s and they are coming out exceptional. This are for myself so I have taken special care. Maybe I'll post the results somewhere.
... So do I !
What could it be below the compression driver with a front horned driver and with a less heavy cone ? (better damping control for more WOW effect à la front loaded cone driver like the one meter front horns ??) (= does a direct 15" is equal to a 8" or 10" front horned driver when it is about live and a compression above?)
Is it true than the flesh, meat of mid can be worked by emphasing the 800/900 Hz range ? While drums needs something fast, well damped below : (50 to 500 Hz? ) ?
Or is it not about delay but also rooms (about making a speaker that works everywhere !)
Sorry I don't believe as far as high efficienty is involved and live not amped music is listened with good reccording that a 15" direct radiator is made for mid bass range (maybe because the compression driver above = for me, there is a dynamic mismatch - dynamic understood here as accelaration factor and not the difference between the weakest and highest spl sound here.)
Of course, maybe if you multiply the woofers if no horn, the result could be different ???
@ pos : how performs your M2 clone (finished ?) please ? Did you compensate the vented response of the flow ports with the direct 15" radiator by MiniDSP ? (or is it not hearable ?)
What could it be below the compression driver with a front horned driver and with a less heavy cone ? (better damping control for more WOW effect à la front loaded cone driver like the one meter front horns ??) (= does a direct 15" is equal to a 8" or 10" front horned driver when it is about live and a compression above?)
Is it true than the flesh, meat of mid can be worked by emphasing the 800/900 Hz range ? While drums needs something fast, well damped below : (50 to 500 Hz? ) ?
Or is it not about delay but also rooms (about making a speaker that works everywhere !)
Sorry I don't believe as far as high efficienty is involved and live not amped music is listened with good reccording that a 15" direct radiator is made for mid bass range (maybe because the compression driver above = for me, there is a dynamic mismatch - dynamic understood here as accelaration factor and not the difference between the weakest and highest spl sound here.)
Of course, maybe if you multiply the woofers if no horn, the result could be different ???
@ pos : how performs your M2 clone (finished ?) please ? Did you compensate the vented response of the flow ports with the direct 15" radiator by MiniDSP ? (or is it not hearable ?)
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That has certainly been my experience. I've spent hours on end measuring, tweaking, moving, aligning by millimeter and delaying tweeters that come in high, like ~7kHz. Yes, I could measure the difference, sometimes, but I could never really hear it. Disappointing, to say the least.
This is very interresting, thanks for this inputt.
I was puzzled by the good review of the last Zu Audio in their price range and the space between the little wave guide and the "big" cone driver ! XO is at 12 K Hz with a first order ! Far to be ideal on the paper, reviewers if sinceers seem to like the result !
I was puzzled by the good review of the last Zu Audio in their price range and the space between the little wave guide and the "big" cone driver ! XO is at 12 K Hz with a first order ! Far to be ideal on the paper, reviewers if sinceers seem to like the result !
I agree 100%. 700 Hz to 7 kHz is where it's at.
One of my summer jobs was working at NASA headquarters during the summer of 1969 (yes, during the Moon landing). As a lowly GS-4 Graphics Aide, it was my task to use a gigantic Burke & James 8x10 copy camera to make negatives of contractor artwork, develop it in the adjacent darkroom, and make positive Vu-graph transparencies for presentations to top brass on the other side of a 3-section rear-projection screen. They couldn't see me, but I could hear them through an array of ceiling mikes, and it was my task to tape-record the proceedings, as well as project Vu-Graph #12-621 on demand (a human-powered version of PowerPoint). I presented endless lists of budget charts, graphics of the Boeing 2707 supersonic transport, the first versions of the Space Shuttle, and various other deep-space programs they were considering at the time.
I had access to a very nice Altec sound system, which had an interesting variety of controls, including a pair of adjustable low and high-pass filters. These were routinely set to 300 Hz and 5 kHz, so the tapes of the conference would be easy to transcribe. My job was to ensure clear, accurate recordings as the bigwigs (which occasionally had Werner von Braun in attendance) hashed out things about various NASA contractors (poor performance, misleading reports, progress of this or that program, future plans, etc.)
When there wasn't a requirement to tape the folks on the other side of the screen, I'd keep the ceiling mikes on, so I could hear requests for Vu-Graphs or project a 16mm movie (there were a pair of 16mm sound projectors as well as three Vu-graph projectors). I discovered that setting the Altec highpass filter to 700 Hz made conversation hard to understand, but still somewhat intelligible. 500 Hz was good, and 300 Hz was completely natural. On the upper end, anything lower than 3 kHz ruined intelligibility ... way too muffled. 5 kHz was perfectly good and sounded like a clear telephone conversation. 7 Hz gave the bonus of better distinguishing the identity of the speaker, but sounded similar to 5 kHz otherwise. (These were steep, probably 18 dB/octave switch-selected filters.) I had re-discovered why the phone company uses a 300 Hz to 5 kHz bandwidth; anything less, and intelligibility drops off really fast. There really is a critical band for understanding speech.
5 kHz is not enough for music, and sounds like not-very-good AM radio. The seemingly small increase to 7 kHz is a big jump in musical quality, while going beyond that is the entry level to what we now consider "high fidelity".
For musical purposes, 60 Hz to 7 kHz gets most of the job done, and was pretty much the standard back in the days of optical soundtracks. It also describes a high-quality floor-standing radio of the Thirties, with a 12" field-coil woofer and a simple 2~3" paper-cone tweeter.
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Reading that, I felt that it's lower for me, down to about 400Hz. But I thought "How do I test that?". Then reading the rest of your post I realized that I have tested it, much the way you did, with high and low pass filters. My results were similar to yours. But I still don't have a weighting system to decide priorities.
I am also interested (since I spent 30 years as a projectionist) what you were using to project 8x10 transparencies. Simple overhead projector? Or something more sophisticated? NASA had pretty good video projection back in 1969, which I think was the G.E. Talaria. Maybe a Hughes.