I kinda think that ship sailed. I haven't heard from those customers from last year either. I think this whole thing put a bad taste in their mouths.
What I might suggest is to run some baseline tests on current TD12S drivers and that way you will have something to check against. Gives a way to test for regression if any components, vendors or processes change. Might be good to publish your baseline measurement data as well.
I think that would go a long ways towards re-establishing confidence in AE. At least I know it would for me.
To me the issue isn't if the speaker would be repaired, but if a production lot was made that was faulty and this was not caught at the factory. From what I am hearing this was the case and that is inexcusable. All manufacturers have the rare bad parts that need to be replaced, but no good manufacturer runs a batch that are all bad and ships them without knowing this.
I test every speaker that I make. It isn't that hard.
I test every speaker that I make. It isn't that hard.
Geez ...
This argument is grinding on and painful to watch because I have respect for both parties involved. Let's settle this. I have two AE TD12S. One is 2+ years old and the other is about 1 year old. Both are new and still in their packing boxes. Does any unbiased 3rd party out there want to test them and report back to this thread??
This argument is grinding on and painful to watch because I have respect for both parties involved. Let's settle this. I have two AE TD12S. One is 2+ years old and the other is about 1 year old. Both are new and still in their packing boxes. Does any unbiased 3rd party out there want to test them and report back to this thread??
I would also like to point out the zoomed resolution of the impedance curve you posted. No matter what impedance curve you look at there will be small blips. Other drivers used in the 3Pi speaker have much more significant bumps in the impedance curve than the ones you measured. For comparison I would like to show the normal scale impedance curve you measured and sent to me.
It's not a surprise to me to see a few little wiggles like these, the AE cones are intentionally designed fairly lightweight, which allows for the HF extension. You see the same thing on lowthers, guitar speakers, the nice BD BD15 (though that has some suspect measures of it's own, no way it's as flat as the BD site claims) and others.
I've never worked with lambdas, though I would love to play with some. Carl, you're in Bakersfield, I'm down in Tustin- if you want to bring 'em by I can do some impedance testing and we can do some (basic) RTA based testing- it'd be enough to confirm yea or nea on the size of these anomalies. We could even pop 'em in my cabs, which have removeable baffles, and give a listen.
It won't be klippel or LMS quality but 5-10dB anomalies will be easy to spot.
That sounds good to me. Please send me your shipping address via email or message and we will work out the details.
Last edited:
well after seven years you'd think the thought and tidbits would be over and the speaker would have been built alreadyMaybe that's why it's so freakishly dismembered? It's not like Congress is building the speaker right?
The speaker already exists in Washington State. Gary Dahl built it three years ago, and has updated it with a Radian 745NeoBe and Great Plains Audio 416 Alnico (8-ohm version) in a 2.5 cubic foot closed-box with UltraTouch filling. The 20~60 Hz range is supported by a TD15H with passive radiators on the left and right sides of the subwoofer box (which sits directly beneath the 416 box). He's pleased with the results, and since he's a classical musician that I've known for more than ten years, I take his assessment seriously. The feedback I'm getting from Gary Pimm is also positive, and these are the two guys that I trust the most when it comes to loudspeakers. I prefer to work in collaboration rather than work alone ... that was one of the most important things I learned back when I was Tektronix.
Bass-horn fans say that a short bass horn sounds better than a single or pair of 15" direct-radiator drivers. Speaking for myself, I don't know. The bass horns I've heard were kind of a mixed lot, some with rough responses with lots of peaks and dips. I'm curious what a short horn with a 515-type driver could do, if it was assisted with 15" direct-radiator sub-bass woofer like the Fane XB15. If the front opening of the bass horn is more than 30" by 30", though, that doesn't work for me. Not going to be building a new house to make room for a pair of refrigerator-sized speakers; it has to work in the space I have.
As for your system or the system of the banned-from-most-forums Cat, they might be good, they might be bad, I have no way of knowing. Since audiophiles have such radically different tastes, and my tastes are different than the majority of audiophiles, there's no way of telling what XYZ system might sound like. All I can do is stumble forward and work with the folks I collaborate with.
Last edited:
A 30 by 30 horn could get you to 120-150 Hz. If you do your research (you surely will) and with the help of people here you could build a midbass horn that will rock your soul with the Altec 515. If you don't need live SPL's then a single 15 direct radiator may keep up but I recommend a line of them or maybe a pair of corner tapped horns. Imagine an Altec A7 flare a bit deeper and free from diffraction and resonance. It will sound real. The bass below is fairly easy and can be sized for your room and SPL requirements.
150 Hz to 700 Hz sounds like a perfectly reasonably goal; a bit more than two octaves, and the GPA 515 Alnico is in current production, not an eBay potluck item. I'm guessing we're talking about a conical or Tractrix expansion, with the lower edge of the mouth on the floor, right?
The 20~150 Hz range is almost trivial, just a pair of overhung, long-excursion 15" drivers, presumably on opposite sides of the subwoofer box in vibration-cancelling pairs, and with their own high-power Class AB transistor amplifier and room EQ.
Gary Dahl posted his measurements of the current-production 515 Alnico's a few pages back; they differ from GPA's numbers. (Note these are 16-ohm drivers, so the efficiency for the 8-ohm version would be 3 dB higher, if the drive is kept constant at 2.83 Vrms.)
The 20~150 Hz range is almost trivial, just a pair of overhung, long-excursion 15" drivers, presumably on opposite sides of the subwoofer box in vibration-cancelling pairs, and with their own high-power Class AB transistor amplifier and room EQ.
Gary Dahl posted his measurements of the current-production 515 Alnico's a few pages back; they differ from GPA's numbers. (Note these are 16-ohm drivers, so the efficiency for the 8-ohm version would be 3 dB higher, if the drive is kept constant at 2.83 Vrms.)
Last edited:
A hypex flare like used in the mid treble horns you have will load the low mid and upper bass better then the tractrix or conical. I really like keeping a horn close to the floor to add the floor reflection, if it is raised more then a few inches you start to loose the coupling but 6 inches or so if fine. Mine are raised about 5" because I filled them with sand and couldn't move them without the help of a friend. So I added casters. They would be on the floor if they weren't so heavy.
The FS on his 515 drivers really seem wrong. What works best for a midbass horn driver is a higher FS, like around 50-60 Hz for a 15. The pair of 515 (like new reconed by my guru reconer) I have here are low too but in the 35 Hz range not 18 Hz. Those probably would not be so great if that's the real resonance of them.
The FS on his 515 drivers really seem wrong. What works best for a midbass horn driver is a higher FS, like around 50-60 Hz for a 15. The pair of 515 (like new reconed by my guru reconer) I have here are low too but in the 35 Hz range not 18 Hz. Those probably would not be so great if that's the real resonance of them.
Last edited:
Hypex sounds good, then. I agree 100% about the floor reflection; beyond a critical distance, floor reinforcement just doesn't seem to happen, and in this frequency range, the presence of the floor image has a strong effect on the subjective impression of physicality and tactility of the sound (piano and cello have a sense of weight and solidity).
What is the effect of rear-chamber volume on horn tuning? I would assume that the compliance of the suspension and the air-volume behind the driver are effectively in series, with the compliance from the box dominating over driver suspension. If the driver suspension is softer than expected, wouldn't a reduction of rear-chamber volume raise the Fs of the driver to the desired value?
What is the effect of rear-chamber volume on horn tuning? I would assume that the compliance of the suspension and the air-volume behind the driver are effectively in series, with the compliance from the box dominating over driver suspension. If the driver suspension is softer than expected, wouldn't a reduction of rear-chamber volume raise the Fs of the driver to the desired value?
Last edited:
The back chamber is there to equalize the air pressure between the front and the back of the cone so it's more linear through its cycle. When it's right the FS is raised and you get a SNAP in the sound that you miss if it's mistuned - the SNAP isn't actually a snap but a point where the fundamentals all seem to happen just right. Like there is no woofer, just sound. If you start out with a low FS driver then you'll probably have a problem with the back chamber in a short horn. Higher FS drivers tune within a box that can actually fit behind the driver.
This should get you some answers: http://isites.harvard.edu/fs/docs/icb.topic897940.files/horns.pdf
http://kolbrek.hoyttalerdesign.no/index.php/horns/horn-theory
http://kolbrek.hoyttalerdesign.no/index.php/horns/horn-theory
Last edited:
I think that's what he's asking. Horns work best when the resonace of the system is close to the flare rate. When system resonance is below flare rate you push it up higher by making the compression chamber smaller. This is why you don't want to start with a driver (system) Fs too far below flare rate because the air impedance load of the horn pushes the effective Fs down, and can make the back chamber required to get system resonance back up near flare rate impossibe
DDS USA made horns
Hi Lynn,
This looks ideal for home use, only 22 inches square, light and easy to position at floor level and has great polar response above 60Hz.
http://www.ddshorns.com/BassMid DVB 15H.pdf
I assume it is lower gain ( only 3.5dB) compared to the larger designs you guys have been talking about, but it would be easy and low cost to build.
If it proved effective maybe one of the 100's of USA contributors to your thread could build a mould to produce custom versions with a matched rear chamber to suit your drivers, I am sure the Polish horn guys at Autotek could do something for the European buyers on a group buy type deal?
Hope it helps
Cheers
Derek.
Hi Lynn,
This looks ideal for home use, only 22 inches square, light and easy to position at floor level and has great polar response above 60Hz.
http://www.ddshorns.com/BassMid DVB 15H.pdf
I assume it is lower gain ( only 3.5dB) compared to the larger designs you guys have been talking about, but it would be easy and low cost to build.
If it proved effective maybe one of the 100's of USA contributors to your thread could build a mould to produce custom versions with a matched rear chamber to suit your drivers, I am sure the Polish horn guys at Autotek could do something for the European buyers on a group buy type deal?
Hope it helps
Cheers
Derek.
Shallow & compact Vs deep and huge!
Hi Gisle,
The J Horn is a cool piece of kit, but huuuuge!
I wouldn't want it in my lounge...Now if win the lottery and build my custom home cinema with false walls all around to hide huge and open baffle monsters then sure, I could easily use 10 or 12 of these!
Cheers
D.
Hi Gisle,
The J Horn is a cool piece of kit, but huuuuge!
I wouldn't want it in my lounge...Now if win the lottery and build my custom home cinema with false walls all around to hide huge and open baffle monsters then sure, I could easily use 10 or 12 of these!
Cheers
D.