I'd love to hear more about the AE TD15M (or H if more appropriate for a driver I don't intend to cross any higher than 700hz). I think I mentioned them being on my list in the first post. At one point before I started this thread, I was *this close* to moving forward with one of the AE drivers.
I think main issue that's had me rethinking that position is the prospect of a long wait time to receive the drivers. I've read more than enough posts from folks who preferred them to JBL 2235 and 2226 to be convinced that must be very fine sounding. I will say I haven't managed to find an account of someone preferring the AEs to Altec 416 in their own system, for whatever that's worth.
Could you share any more of your experience with them?
The older I get, the less enthused I am about the prospect of trying to match 50 year old drivers. I've been almost strictly vintage Altec pro stuff for several years, having owned 9844s, which I restomoded to vertical orientation with external horns, eventually driven by GPA's alnico 802s, 604e, 604g, a Model 19 ground up resto, Boleros - with that killer 10" 406-8Y driver. I don't remember what else. Even with GPA refurbs of great condition, domestic-use only components, I've found it exceedingly difficult to find two same model drivers with inaudibly small variations in response. I get it's due largely to age and the sheer density of their detail retrieval. That's a long way of saying the thought of having drivers that are matched out of the box is tempting.
I should say the new manufacture GPA alnico 802s and ferrite 902s were balls on matched and stayed that way. Never should have sold them!
I think main issue that's had me rethinking that position is the prospect of a long wait time to receive the drivers. I've read more than enough posts from folks who preferred them to JBL 2235 and 2226 to be convinced that must be very fine sounding. I will say I haven't managed to find an account of someone preferring the AEs to Altec 416 in their own system, for whatever that's worth.
Could you share any more of your experience with them?
The older I get, the less enthused I am about the prospect of trying to match 50 year old drivers. I've been almost strictly vintage Altec pro stuff for several years, having owned 9844s, which I restomoded to vertical orientation with external horns, eventually driven by GPA's alnico 802s, 604e, 604g, a Model 19 ground up resto, Boleros - with that killer 10" 406-8Y driver. I don't remember what else. Even with GPA refurbs of great condition, domestic-use only components, I've found it exceedingly difficult to find two same model drivers with inaudibly small variations in response. I get it's due largely to age and the sheer density of their detail retrieval. That's a long way of saying the thought of having drivers that are matched out of the box is tempting.
I should say the new manufacture GPA alnico 802s and ferrite 902s were balls on matched and stayed that way. Never should have sold them!
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I had a pair of TD15M woofers, actually the pair Gary Dahl had purchased on Lynn’s behalf back when they were considering it for the Beyond the Ariel project. On that thread, at this point begins some conversation about that driver, with some input by Jon at AE. Further down the thread there is some discussion regarding a resonance between 700-800Hz. It’s eventually determined to have been due to some mechanical cone/surround interaction. I held onto those drivers for a while until I scooped up a used pair of 15pr400s which I preferred for being more lightweight and without the resonance issue.
After that a used pair of GPA 416-8B at a great price caught my eye. I bought them, measured them and found the pair to be better matched than the 15PR400s. So out they went. If it hadn’t been for storage issues (we still rent), I would have held on to all three pairs rather than just the 416-8B drivers.
So there you go, not much of use subjectively but the thread link above gets nice and contentious if you like that sort of thing.
After that a used pair of GPA 416-8B at a great price caught my eye. I bought them, measured them and found the pair to be better matched than the 15PR400s. So out they went. If it hadn’t been for storage issues (we still rent), I would have held on to all three pairs rather than just the 416-8B drivers.
So there you go, not much of use subjectively but the thread link above gets nice and contentious if you like that sort of thing.
I haven't been able to find plots for the 1603. Forgive my ignorance... I'm not positive I understand have you are getting at with the attached plits. I haven't googled thoroughly enough to find polars for the TADs. Are they significantly different from the JBL/Altecs compared here?
I wonder if these polars might to some degree explain my preference for lower crossover points? Even with my thrown together networks, I really prefer the tone and density of the overall presentation using the 515ish LF section of my 604g in 620 cabs crossed at 800 to the Gauss 4" driver to the Alrec 604 with phase corrected Markwart crossovers. Aside from being more exciting to hear, and enjoyable for long listening periods, they convery more of the information in reference recordings I long ago thought I knew to the smallest nuance.
The attached document was eye opening. Imagine my surprise when I discovered some months in to furtzing around with dual 414s - the first Altec design I modified - that the very slight edginess I had long attributed to the compression drivers on various horns in that setup was actually coming from the 414s themselves, not the cds. I think that's when I went back to the stock 800hz crossover point.
I think I've ruled out TAD for the time being. Focusing
on the 2216nd, the 416 and current production drivers.
Oh yeah - that reminds me.... given that I'm currently running the LF of the 604-8g in Altec 620 ~9 cu ft enclosures (albeit originals that would be improved upon by newly built identical cabs), and will be moving to smaller, newly (and very well) built ~6.8 cu ft Iconic/612 replicas, I'm wondering if even the 416 would give me the LF performance improvement I'd like to achieve.
I've been guesstimating the 416 would be an improvement over the 604 from ~120-600hz in the 612. Even in the 620 cab, my subjective impression of the 604g low end is that 'it's all there' or mostly there, but certainly isn't as rich and muscular as the midband. It's quick and articulate...but, again, subjectively, doesn't provide an adequately firn foundation for the rest of the audible band. Nothing approaching the 416 in cabs of similar volume to the 620.
In fact, I've only run 416s in Model 19 cabs. Actually, strike that...I ran Vals briefly , but in a bad room. I need to run winISD to see what kind of penalty I'd pay were I to run the Altec 416 in the smaller 612 cab.
This quandry is what got me looking into JBL et al in the first place....drivers that would not be as compromised as the 416 in tiny enclosures like the 612.
I've got a buddy with 416a in ported Val/Heathkit enclosures with horns removed. Need to give them a listen again and calculate the volume.
BTW, do you have any personal experience/observations re: the 2216nd?
Thanks again for your input!
Thanks for the tip on the AE drivers and sharing your experience - it's really helpful. Any subjective thoughts of your recollection of the AE drivers vs. the 416? You're the first person I've come across to have owned both.
I hear you.... I sold my GPA 802s just weeks before the GREAT GPA PRICE HIKE, which took place a couple years before the 'post-COVID 1.0: the world's lost it's mind' price hike' of the whole market for these devices.
Never thought I'd see market forces push Altec devices past those of the high end modern pro audio world (let alone the hifi world), but it looks like we're headed there if not there already.
I should have known we were headed for trouble when the price of reclaimed barnwood in Nashville exceeded structural timber back in '14.
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@Baaronji
Brinkman has mentioned Gary Dahl.
It's worth isolating ( Ghosting ? ) all of Gary's posts within that same linked thread to help find the one where Gary briefly compares the GPA 416 to the AE TD15 model .
He ended up preferring and keeping the 416 and then running it in a 3 cu' (?) sealed box that sat on top of another 15" doing sub 80hz ? duties .
This was done for space reasons also ( I think ) > it's worth reviewing his articulated experience .
His approach seemed eminently logical when I read it .
🙂
Brinkman has mentioned Gary Dahl.
It's worth isolating ( Ghosting ? ) all of Gary's posts within that same linked thread to help find the one where Gary briefly compares the GPA 416 to the AE TD15 model .
He ended up preferring and keeping the 416 and then running it in a 3 cu' (?) sealed box that sat on top of another 15" doing sub 80hz ? duties .
This was done for space reasons also ( I think ) > it's worth reviewing his articulated experience .
His approach seemed eminently logical when I read it .
🙂
I did take a REW measurement the other night agmonst all the chaos surrounding my current pair of 16ohm 15m in a 231 liter box....there was a resonance at 500hz that seemed out of place...Ive got bigger issues at the moment. My specs aren't lining up and qts, Motor strength and efficiency are way off and below expectations...mistakes hsppen and what's important is how we handle them...hopefully John is an honest business man and will make sure I get the product I paid for....at this point I havent heard from them in 3 days...I've been pulling 15 hr days and would laugh at the idea of being too busy to return an email.
I say my prayers....this thread is here in great timing. The design in my thread is looking for the same as this thread title... if Acoustic Elegance refuses to return the faulty driver they sold mr, then who will be my savior? (Outside of a lawyer lol)
I say my prayers....this thread is here in great timing. The design in my thread is looking for the same as this thread title... if Acoustic Elegance refuses to return the faulty driver they sold mr, then who will be my savior? (Outside of a lawyer lol)
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The other 15” was another AE driver from the TD15 series, tuned low using using dual passive radiators.
Hey Camplo - really appreciate you chiming in. Our projects are really similar. I had resolved to read your entire thread - there's so much good info there - and made it about half way through, then clicked a link someone sent me yesterday and found myself at the very end of the thread - as all this has been unfolding over the past few days (felt like skipping to the last chapter of Crime and Punishment). I was crestfallen to read about it and I hope you're able to get it sorted out to *your* satisfaction. I'll be watching keenly to see how it turns out.
Not sure if you're willing to go there yet - and apologies if you've stated otherwise elsewhere - but do you have any replacement driver candidates in mind if the AE don't work out?
I don't remember seeing the JBL 2216ND suggested in your thread - at least as far as I had read into it. Anyway, having read so much of the saga of your development phase, I wish I could be of more assistance.
Looks like I'm more or less down to the Altec 416 (I'm partial to the later -8b model, though audible differences between the alnico 416s are more likely to be due to age and what kind of lives they led before you get ahold of them), JBL 2216nd, and a maybe a couple of the better modern pro drivers people have mentioned in this thread and in yours.
I'm reluctant to write the TAD 1603 off, even though I've every reason to believe the 2216nd would out perform it. To my thinking, the early TAD drivers are like the Magnum P.I. Ferrari 308 gts of speakers, what can I say?
As far as the new production GPA alnico drivers go, I've owned a few, and they have been uniformly exceptional. Bill at GPA routinely fills orders for scores or more of these drivers for demanding pro clients around the world, and in my limited experience, their quality is reflective of that demand. Bill would never advertise something like this (although, speaking as a marketing type, he probably should), but I've had past orders delayed by a few days because Bill was scrambling to fill an order for 60 or 80 alnico 802s for a European client. Point being, they're not as niche as it might appear.
Candidly, the main reason I haven't jumped straight to the GPA alnico 416 is because I worked with them extensively before the price jump a few years back, and still experience sticker shock when I see 400% increases. For sure they were underpriced before and needed to be raised. I have no knowledge of any of the machinations behind the move, but it certainly 'felt' like what happens when skittish outside investors wanna get handsy with operations. Complete conjecture on my part.
Not sure if you're willing to go there yet - and apologies if you've stated otherwise elsewhere - but do you have any replacement driver candidates in mind if the AE don't work out?
I don't remember seeing the JBL 2216ND suggested in your thread - at least as far as I had read into it. Anyway, having read so much of the saga of your development phase, I wish I could be of more assistance.
Looks like I'm more or less down to the Altec 416 (I'm partial to the later -8b model, though audible differences between the alnico 416s are more likely to be due to age and what kind of lives they led before you get ahold of them), JBL 2216nd, and a maybe a couple of the better modern pro drivers people have mentioned in this thread and in yours.
I'm reluctant to write the TAD 1603 off, even though I've every reason to believe the 2216nd would out perform it. To my thinking, the early TAD drivers are like the Magnum P.I. Ferrari 308 gts of speakers, what can I say?
As far as the new production GPA alnico drivers go, I've owned a few, and they have been uniformly exceptional. Bill at GPA routinely fills orders for scores or more of these drivers for demanding pro clients around the world, and in my limited experience, their quality is reflective of that demand. Bill would never advertise something like this (although, speaking as a marketing type, he probably should), but I've had past orders delayed by a few days because Bill was scrambling to fill an order for 60 or 80 alnico 802s for a European client. Point being, they're not as niche as it might appear.
Candidly, the main reason I haven't jumped straight to the GPA alnico 416 is because I worked with them extensively before the price jump a few years back, and still experience sticker shock when I see 400% increases. For sure they were underpriced before and needed to be raised. I have no knowledge of any of the machinations behind the move, but it certainly 'felt' like what happens when skittish outside investors wanna get handsy with operations. Complete conjecture on my part.
No subjective impressions of either, sorry but I can add a couple more observations regarding the build of these woofers.
The TD15M are very pro-sound in terms of ruggedness and compliance of cone/spider/surround. They are very much like the 15” drivers I handled at Meyer Sound when I worked as a loudspeaker assembler and also when I was trained to make woofer cones and cut surrounds and spiders there. Just very overbuilt and with less give.
The FaitalPRO 15PR400 is much, much more like the 416 in the above regards. When I talk about compliance of the cone/spider/surround, I’m referring to the resistance to motion when you spread your fingers around the dustcap and gently press in on the cone. Both the 15PR400 and 416 feel less overbuilt and have the same nimbleness, which just feels more appropriate for domestic power requirements using woofers with these sensitivity levels. I just wish there were shorting rings on the FaitalPRO.
Another piece of advice is to not get too hung up on cone materials. A “paper” cone driver isn’t quite as simple as it sounds. There’s a lot of materials that fall under the descriptor “paper” and these can be combined in varying quantities, along with other admixtures before being processed through the hydro-pulper. A few steps later, after the cone is formed and passes QC, there’s still further treatment that can be done on a paper cone. I don’t precisely know what these treatments are (nor would I be at liberty to say) but it’s pretty obvious that paying attention to the cone perimeter (where it interfaces the surround) and further treatment of the cone itself are all areas that separate the men from the boys and it looks like it may have been a problem area for AE, hopefully that’s been resolved by now.
I agree. The $500 I spent on a used/like new pair of 416-8B drivers did not seem inexpensive at the time but feels like an absolute fire sale now.
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Regarding the price jump....That is likely the product of supply demand....They likely figured out how superior their product was (or remained into the new generation of woofers) and went for it...Non the less. Here we are
I just checked out the specs for that driver, in particular, looking for the Xmax spec. My design is essentially a tmm 2.5way with a high pass on the top woofer to control excursion....
I don't understand woofers well enough to know why one would want a short xmax....I can theorize but I rather have it explained by the ones who already been there done that. Any takers lol. In my mind....thd is whats at xmax...the farther away I put xmax....the cleaner the signal.
I haven't jumped back through to read what I've missed in this thread but I did catch before, that the 2216nd has a cult following regarding the technology used in this woofer and I know it has a decent xmax...I cannot find it via google but I had the engineering papers on the computer downstairs....I'm pretty sure it was dbl digits....at least 10mm...The mms seemed high to me but if it has a cult following it must be a driver good for something....in my opinion it is good for mids and bass? Not king of either? Like an 15" version of a Acoustic Elegance 18H+...Complete speculation based off mms btw....
I dunno whats going to happen with my current drivers...I feel jaded, but only because I haven't heard a word from Acoustic Elegance. There are more issues popping up every day as I dig deeper...I predict that there was some type of fluke in a production run due to the sourcing of new components that they went through....I'm seeing stuff in the impedance plot of 15m that shouldn't be there....I'm seeing stuff in a pair of18H+ impedance plot that either was not there before or I just happened to only measure a good woofer in past or its due to the enclosure.... I've still not measured with the DATs, 2 other 18h+'s...It was easy to keep the pairs separated since one pair came with no phase plug....which I received the phase plugs later....I predict that these are the faulty drivers, since they came with the 15m's......and I did measure upon arrival, the last pair of 18h+'s to which I have a record of having a perfectly normal impedance plot.
Since my last measurements of the 15m, I have confirmed the drivers to be defective, having a very strange set of thiele specs....I'm just waiting to hear something....anything....from John. Which will likely be the difference between the AE drivers staying with the project or a full return for refund or small claims court
If the latter 2... I will be on to the next best thing and it seems like the JBL 2216nd vs the Altec 416 is about where I am at.
You can clearly see the difference in diaphragm profiles Vs the [solid line] rigid piston, which in turn gives someone with a bit of experience how the polar responses differ, but only the former was specifically for you, i.e. you can copy it and connect the dots [symbols] for a graphic view that most folks can't 'see' in a polar response measurement.
The TADs ~mirror JBL [or at least the originals], so seen one, 'seen' the other....... at least up to its mid-band where differing doping/whatever normally determine's a driver's 'signature', the part of the BW up to its HF limits that sets XO point/slope/whatever personal sonic preferences.
Dunno, less acoustic efficiency [smaller box volume [Vb]] = higher corner frequency, so potentially a 'fuller' mid-bass lower mids [~ 60 Hz- up].
OK, T/S box design theory peters out at a driver's upper mass corner [Fhm]:
Fhm = 2*Fs/Qts'
[Qts']: [Qts] + any added series resistance [Rs]: Calculate new Qts with Series Resistor
[Rs] = 0.5 ohm minimum for wiring, so may be higher if a super small gauge is used as a series resistor plus any added resistance from an XO/whatever.
From this and published specs it's obvious that the box will have little/no impact on the 416's ~ 154 Hz and the 604's ~186 Hz Fhm's.
In short, none above these points from box loading, though their differing baffle areas, widths will change their polar response below ~ 800 Hz.
Below these points, the 416 has a flatter response due to less efficiency*, so yields a perceived 'fuller' [mid] bass below ~70 Hz.
* This is why I say 'perceived' since one is always trading efficiency for [flat] BW.
So with that in mind, I prefer the [now ancient] 515's mids/HF 'sweetness', so after a brief love affair with my 803B/416A loaded DIY A7-500 pair, switched and EQ'd them to get the 416's frequency response = best of both 'worlds' for me. 🙂
No, though would like to, but don't know of any in the metro Atlanta area.
You're welcome!
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From just reading about the JBL builds, specs it's a 'HIFI' Vs a vintage's somewhat 'colored' performance, so for any SOTA high accuracy apps, seems a JBL 'no brainer' choice to me.
For me Tad as a reputation to be the ultimate in terms of accuracy. They provide solid engeenering and the measurement of their compression drivers are impressives, look here. It would surprise me that TAD make poor woofer to go with them.
Nelson Pass said not long ago that the TD-1601 was the best woofer he heard. John Stonczer replaced his VOTT with TAD 2404.
Do not forget that any piece of equipement are colored because they all produce distortions. Every electronics instruments, every system is a compromise. In the end it is the best compromise that YOU have decided to assume that matter.
Nelson Pass said not long ago that the TD-1601 was the best woofer he heard. John Stonczer replaced his VOTT with TAD 2404.
Do not forget that any piece of equipement are colored because they all produce distortions. Every electronics instruments, every system is a compromise. In the end it is the best compromise that YOU have decided to assume that matter.
Some less than others...but we could still find another way to level the playing field, likely. There are distortions that aren't labelled distortions yet for some reason...Decay is a distortion, compression is a distortion, rise to peak energy is a distortion...reflections within the room are a distortion, colored off axis response is distortion is some type of way. No need to argue about where to draw the line, just trying to make a point. Its nice when the system creating the sound isn't a major contributor...
While designing my system we focused on lowering distortion with large midranges, 15"s to be specific...but I'm certain that a 4" midrange will have a tighter decay profile....traded one distortion for another....I think the 15" stand out by being able to cover more bandwidth? I don't even know if thats true lol....Direct energy increase via directivity is likely a main factor.
hi, anyone knows the coil inductance of the GPA alnico/ferrite drivers?
thanks in advance.
cheers
Henry
thanks in advance.
cheers
Henry
My various AlNiCo drivers were in the ~0.5 - 2.5 mH range with MI drivers on the low side, but don't recall seeing any measured ceramic ones, so best to run T/S specs, impedance plot to calculate if DATs/whatever doesn't do it: Le = 1.592 * 10-5 * (R10 k – Re^2)^0.5
Hmm, for both to have the same size VC, Fs, BW, but with one having a ~14x larger area [Sd], wouldn't their air load mass [Mms], compliance [Cms] need to be similar if not the same, 'ipso facto' have similar/same settling times?
In short, the gain here is efficiency and why the pioneers had to do it.