Hi Lynn,
I won't be at that show, but I just wanted to chime in on the Woofer choice.
May I humbly recommend you check out the Fostex FW405N too?
Their T-S parameters may not look the best according to conventional wisdom, but having lived with them for over 18 months now, I can honestly say that they do sound much "sweeter", more "natural" and "un-wooferlike" than many (most) other 15-inchers I have ever heard. I personally believe it has something to do with the combination of a very low Rms, low Fs/Qt (allowing an overdamped bass-reflex box tuned low and with excellent group delay), and a very stiff and well-behaved cone (the single broad peak at ~1800 Hz is easily taken care of by a parallel LRC).
Just my 2 cents.
Cheers,
Marco
It was hardly an exhaustive comparison, simply between the JBL 2226J (16 ohms) and the old/new Altec/GPA 416 Alnico (16 ohms). Both were 3rd-order lowpassed at 700 Hz, the bass cabinet tuning is similar, and annoyingly, the bolt circle diameter and cabinet opening are different.
Result: they sound completely different, like two different speakers by different designers. By measurement, nearly identical, except the 416 Alnico, against expectation, is about 2 dB more efficient than the JBL, and the Qts is lower. Easy to compensate for in the crossover, since the Radian 745Neo is an astounding 115 dB efficient (and flat), and it's just a matter of how much attenuation is needed for the HF system.
I really liked the 416 Alnico. In the bass and lower midrange, it was similar to the sound of the Oswald's Mill loudspeaker that uses the same bass driver, with vivid tone colors and realistic, in-the-room grand piano, with a real sense of presence and weight. The tone colors with the JBL were pale and subdued, and the subtle microdynamics you'd expect from a high-efficiency loudspeaker were not there. I'm very used to the sound of the 92 dB/meter Ariels, and the JBL was duller and less dynamic, more like a mainstream high-end speaker. No idea why; the engineering in the 2226J is superb, and like all JBL's, they look fantastic. Some might say the JBL was "accurate", but in my experience, live music has intense tone colors and very strong sense of presence, and so-called "accurate" systems fall down pretty badly at reproducing acoustically sourced music.
I have not auditioned (in a system I'm familiar with) the French exotics. Many moons ago, at the 2004 ETF in Europe, the French field-coils were controversial ... some people loved them, others didn't like them at all (kind of like Manger). So I have no idea at what they sound like.
Altecs, particularly the Alnico-magnet versions, have quite a following in Europe, both the French and the Germans like them ... a lot. Having made them a part of a system that I designed, with my set of esthetic and technical decisions, let me know the character of the driver better than a random listening session at a show.
If I was really over the edge, I'd consider the Wolf von Langa field-coils, but the latest models don't look like there's much Altec left in them (cones, surrounds, etc.). It would be interesting to hear if anyone at the RMAF is using these drivers. The Wolf von Langa and TAD professional drivers occupy the stratosphere of high-end 15" drivers, but as always, I like to listen for myself. The simple JBL versus Altec/GPA comparison has shown me the sonic differences are much larger than I expected, and unfortunately, the measured specs may not be a guide to how they sound.
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Before I went to Dallas in the spring of 2012, I ordered a pair of AE TD-15M's. After I returned, I tried to cancel my order, but AE didn't accept the cancellation. Since I didn't need them any more (having settled on the GPA's), I told AE to send the pair to my friend in Washington State, Gary Dahl.
One year after I ordered them, Gary received the pair of TD-15M's ... minus the polished aluminum phase plugs. Those arrived a month later.
Even if the TD-15M's are the best drivers in the world, that's too long to wait, no matter how good they are. Although GPA has had their QC gremlins, Bill's easy to work with, and I've never heard of anyone waiting a year for a production-model GPA loudspeaker.
I've special-ordered Alnico-magnet drivers from GPA three times ... a pair of 288's, a pair of 414's, and the pair of 416's that are still in Dallas, and they all arrived in timely fashion.
I'm used to working with vendors on special projects: I carry the extra costs, and get the first working versions. That's what happened with the AH425 Azurahorn, the three GPA models mentioned above, and various transformers for other projects. I even had a small role in urging JJ to put the 7119 vacuum tube in production. I don't mind if a vendor sits on a proposal of mine for months, or even years; my offbeat suggestions don't necessarily add to their profit, and all of these businesses run on very small margins.
On an unrelated note, I'm embarrassed to admit I'm starting to agree with Romy the Cat. He's right that the 200~400Hz part of the spectrum is the part that really matters, and it's a portion that many vendors get wrong.
There's a lot more there than Baffle Step Compensation (BSC); even for bass drivers that are piston-band flat and loafing along in a low-distortion part of the spectrum, there's still plenty of additive coloration, as well as the inverse of coloration, missing tone color and dynamics. The drivers do sound different, even though FFT's and distortion measurements tell us little why this might be so.
He's also right that a serious designer needs to have a personal esthetic, not just engineering chops, otherwise you can get lost in the weeds and chase trivial problems.
There's a lot more there than Baffle Step Compensation (BSC); even for bass drivers that are piston-band flat and loafing along in a low-distortion part of the spectrum, there's still plenty of additive coloration, as well as the inverse of coloration, missing tone color and dynamics. The drivers do sound different, even though FFT's and distortion measurements tell us little why this might be so.
He's also right that a serious designer needs to have a personal esthetic, not just engineering chops, otherwise you can get lost in the weeds and chase trivial problems.
Glad to hear they're back in production; the rumor I heard was that frames, for some strange reason, were hard to get from the overseas vendor. My other (minor) beef with the AE's is the mandatory ceramic magnet; neodymium, Alnico, and field coils are not an option, and I suspect I'm now at the point where I can hear the differences in magnets (in drivers that are otherwise similar). I'm not in the field-coil camp just yet; the drivers I've heard with Alnico sound good to me, and the field-coils don't seem to have any special sauce that distinguishes them from Alnico.
The other thing to look into is a short horn ... although even the smallest bass horn adds additional delay compared to a direct-radiator array, which requires the AH425 to move backward by a corresponding amount (no, I don't want to use digital delay).
Still, a possibility under consideration is a compact bass horn, with an added "helper" direct-radiator on the side of the cabinet, which would augment radiation below the cutoff of the bass horn. The bass horn would cover 700 Hz to 200 Hz or so (depending on size), and the helper driver would come in below 200 Hz.
Since the bass horn effectively becomes a direct-radiator below cutoff, a second direct radiator could offset the loss of efficiency in the 50 Hz to 200 Hz region. Since it's unlikely that the added efficiency would exactly match the loss of horn-gain, the helper driver might need its own amplifier ... hmm, getting complicated, and room-tuning might get messy.
A pair of 15" drivers or a quad of 12" drivers might be simpler.
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Very messy, this will never sound right and will take forever to realize it after lot's of sawdust and chin scratching. It's best to use all horns at least down to 100-120 cycles and be done with it.
Romy had me wind a slug coil for his favorite compression drivers, in place of the Alnico slug. He was able to vary the gap gauss up to 1.9 tor as I remember. He never could find a median that satisfied him, because it did not give him a blend of the factors he liked at either end of the gauss range he was experimenting with.
As for your worry about external bass drivers, you may only need a phase control in a plate amp driving the extra woofer to arrive at exactly the time interval you are listening for. Another useful function in my system is in controlling the lateral spread of the sound reproduction stage. I had not realized it is the relative bass phase, and in very fine increments, that controls the lateral spread for the entire frequency range. I do have an additional driver running from 300 Hz open baffle down to where ever, so it may be the phase difference in the common frequencies between the TL tower under phase control and this driver that actually provides this effect. In any event, once I am in the correct range, which turns out to be 45 degree lag with the series crossover, just a few degrees of knob turn makes a large difference.
As for your worry about external bass drivers, you may only need a phase control in a plate amp driving the extra woofer to arrive at exactly the time interval you are listening for. Another useful function in my system is in controlling the lateral spread of the sound reproduction stage. I had not realized it is the relative bass phase, and in very fine increments, that controls the lateral spread for the entire frequency range. I do have an additional driver running from 300 Hz open baffle down to where ever, so it may be the phase difference in the common frequencies between the TL tower under phase control and this driver that actually provides this effect. In any event, once I am in the correct range, which turns out to be 45 degree lag with the series crossover, just a few degrees of knob turn makes a large difference.
Hi Badman, if you go back through the umpteen thousand posts you'll see two main themes which would rule this out:
- Low Qms (4.5)
- Ferrite Magnet
Hi,
Is there anybody in here who take haralanov approach?
GoodSoundClub - Romy the Cat's Audio Site - Canadian Speaker Proposal
GoodSoundClub - Romy the Cat's Audio Site - If you were to start from scratch, what horn system would you build?
Caninus
Is there anybody in here who take haralanov approach?
GoodSoundClub - Romy the Cat's Audio Site - Canadian Speaker Proposal
GoodSoundClub - Romy the Cat's Audio Site - If you were to start from scratch, what horn system would you build?
Caninus
Canindus,
i wonder why nobody asked or questioned Haralanov. It seemed everyone was familiar with his vocabulary and explanations, like :
If you'd ask me, i'd understand absolutely nothing about what he said.....
Then you have basically a Avantgarde Trio approach; to get down to 100 cicles, you need at least a 35" horn. Something to observe , after i compared my 38" lower midrange horn / Fane Studio 8m channel, to Beyma 12p80nd/90l cab, beside their own inherent tonal characteristics, was integration. If you have a big room, it might be ok. But at 4 meters listening distance, i observed how bad integrated my bass line array with lower midrange horn was. I don't know how i could manage it better, its certainly not a crossover issue, but in my view, the physical distance, because of the size, they cannot be brought closer together. Just one driver covering bass and midrange is a better compromise in this regard. Comb filtering is no issue for such a range.
I had Altec 19 in the past, it had VERY good lower midrange, i liked it a lot. Very vivid tonal colors, certainly nothing to miss..... My reference however is Beyma 12p80nd, which beats my lower midrange horn hands down. Much more vivid, natural and even dynamic, and perfect integration with TPL. Had in the past Beyma 15" LX60, which is a copy of Jbl 2226. Sad i don't have it anymore. That in a very solid bass reflex box was one of the finest and best sounding woofers i had so far, but only up to 300hz, which is its limit.
Angelo
You surely don't need a 35" round horn to get down to 100 HZ. Just use a good 12 or 10 inch driver that will get to 700-800 in a straight front horn and make it rectangular. This keeps the size and driver spacing within reason. An 80 Hz flare 1/4 space horn isn't really that big. Round horns are a fad and really aren't always the best solution.
Given the differences you heard and the emphasis on the tonal colors have you considered looking at the Tone Tubby Alnico again?
I think true, more like up to 700Hz, but perhaps only because the spectrum above this is relatively easy to get right with a good compression driver and suitable horn. The low / mid is just a lot harder. If there were more of a problem with the mid / highs then we would say this was the key to it all.
My feeling is that low mid / bass horns actually do the job with minimum fuss, if you are prepared for the lack of clout we expect with hifi bass, (which to my ears is more like pa). My L shape 50Hz ¼ WL horns with Vitavox K15/40 drivers disappear in the soundstage mix and I have no sense of the drivers at all. (TD15M, GoTo, even Lowther on a longer horn did the same thing). In contrast, the 15” AE drivers in Onken enclosures are heavy hitters – but showy. My tastes in music and presentation have become a lot more discerning.
But I don’t think there is much avoiding the fact that a CD on a 400hz horn fits best with a direct radiator enclosure. If it comes down to ‘the sound’ of a particular driver, I guess the task is still to find out what makes this happen - before it goes out of production, and creates another lode of Unobtanium.
It is surprising how low an Avantgard type mid horn will go. I have made several 160 Hz JMLC horns with 4” throats for folks with Fane 8M drivers, and recently modelled it out of interest. The ‘reactance annulling’ peak at 70Hz is impressive. But the value of a 160 horn to me is to bring down the cross over point to the bass horn. I have made long 160 horns for Yamaha 6681B, for 288, for GOTO drivers and for LM555W. The long horn can hang over the back of the bass horn and approach better alignment. There is lots of overlap for 1st order cross overs (OK if you don’t crank it). I have done some dwgs for an all ply version of the bass horn I will try and put up on the website. In some ways, like SE triode amps, horns make it possible for the amateur to get great results (without all the Hegelian drama on Romythecat).
