Well, a couple of factors:
1)I figured that this being my first build, I really wouldn't have a sense of what the differences were.
2) Cost played a small part in the equation. I considered that again being the first build, I would spend alot on playing with XOs in the future, and that may make a bigger difference.
3) My room is not anywhere near ideal..... chances are whatever differences there were would be a wash
4) If the people making the drivers, with all the years of experience and being intimately involved in Altec from when they were working there and now making their own improved version of the drivers said that the S3 sounds the same as the E, who am I not to believe them?
5) I realised one thing, that for the longest time I was considering the GPAs as a replica of the Altecs, and that was not fair. If taken by their own merit with no association with Altecs at all, the S3 is a superior driver.
That's my juvenile opinion anyways for what it's worth.
1)I figured that this being my first build, I really wouldn't have a sense of what the differences were.
2) Cost played a small part in the equation. I considered that again being the first build, I would spend alot on playing with XOs in the future, and that may make a bigger difference.
3) My room is not anywhere near ideal..... chances are whatever differences there were would be a wash
4) If the people making the drivers, with all the years of experience and being intimately involved in Altec from when they were working there and now making their own improved version of the drivers said that the S3 sounds the same as the E, who am I not to believe them?
5) I realised one thing, that for the longest time I was considering the GPAs as a replica of the Altecs, and that was not fair. If taken by their own merit with no association with Altecs at all, the S3 is a superior driver.
That's my juvenile opinion anyways for what it's worth.
For the back panel, it's easier to use something like weather stripping.
For the driver basket gasket here's what I have done with silicone caulk. With the cabinet on its back, use masking tape and tape around where the driver mounts. This will do two things. One it will catch the excess bleed out and two it allows you to remove the gasket in the future. Place the driver in the hole and mark the outside circle with a pencil.
Next you oil the driver basket flange where it contacts the cabinet. Just use your finger to smear it on. This prevents the silicone from sticking to the basket.
Next you apply a silicone bead to the masking tape inside the pencil line.
You then place the driver into the mounting hole and let it squeeze out some excess caulk. Use a nail or two to ensure the mounting holes are aligned. With a nice heavy driver it will displace enough caulk that you need not add weight. Leave it overnight or even a whole day. After mounting the driver, trim around the flange with sharp knife and remove the excess caulk bleed out. You know have a custom gasket that doesn't actually stick to the basket and can be pulled of the cabinet as there is masking tape under it.
Either that or you can just use rope caulk. Use a hair dryer to warm it before mounting the driver.
You can also make gaskets from foam tape, EPDM or any number of things. Whatever you have on hand.
It's all about stiffening the cabinet and reducing resonance. The bracing helps break the cabinet into smaller pieces which excite at a higher frequency. The higher the frequency of cabinet resonance, the less you notice it. I think propping the driver is an extension of that but others might want to comment.
It's your guess, but you can be sure that alignment/tuning will change with position of the port.
Post a nice drawing for us... (or link)
I haven't checked any numbers on box or port tuning, but a first glance tells me that it's very large indeed for a reflex loaded S3 driver.
Another thing to consider is that you may want a wider baffle. This tends to be a matter of preference, but something between 24" and 30" wide has generally worked well for me. I tend to think that width is a bit more tolerable without BSC, and it's no more difficult to deal with when you get around to adding BSC to your crossover.
As far as bracing goes, these are big, resonant panels. You'll probably want to tighten that up a bit more. Other folks here are going to have more experience than I do, so you'll probably get better advice from them.
Another thing to consider is that you may want a wider baffle. This tends to be a matter of preference, but something between 24" and 30" wide has generally worked well for me. I tend to think that width is a bit more tolerable without BSC, and it's no more difficult to deal with when you get around to adding BSC to your crossover.
As far as bracing goes, these are big, resonant panels. You'll probably want to tighten that up a bit more. Other folks here are going to have more experience than I do, so you'll probably get better advice from them.
It's the size recommended by GPA. The outline you see on the drawing is because the port is rounded and therefore appears larger on the outside.
I can't have a wider baffle due to space constraints. That is why the cab has gotten deeper and taller.
So even with a 1" ply, cross bracing on the panel and a stiffener in the middle, it won't be enough? Do you reckon I should go with 2 horizontal stiffeners instead? It is pretty tall, but between the driver and port I can't see where I can add another stiffener and have it being meaningful.
I can't have a wider baffle due to space constraints. That is why the cab has gotten deeper and taller.
So even with a 1" ply, cross bracing on the panel and a stiffener in the middle, it won't be enough? Do you reckon I should go with 2 horizontal stiffeners instead? It is pretty tall, but between the driver and port I can't see where I can add another stiffener and have it being meaningful.
OK, fair enough, there’s no technically right or wrong choice per se between these two.
That said, for others who may ultimately use this thread as a guideline……….
1] Since you haven’t auditioned either, this is irrelevant. It’s all about matching up the driver technology that best overall meets the needs of your app.
2] A major issue for most of us, though the E2’s horn can potentially make the XO cheaper/easier to dial in IF it’s at least as large as the original’s and especially if it’s been ‘improved’ in any significant way as GPA implies.
3] Few are and where the major sonic differences are between these two duplexes are well above the room’s influence, so not an issue.
4] Hmm, this statement was made WRT AlNiCo versus Ferrite right? If not, then based solely on the two speaker’s published measured responses, I find this very hard to believe.
5] Overall, I tend to agree from a technical POV.
All that said, from a solely technical POV, I believe the E2 best overall meets your various performance goals IF its horn is at least as large as the original’s and especially if it’s been improved in any significant way as GPA indicates.
GM
Hi GM,
Your thoughts are invaluable as always. As you know I was at a crossroads between the two drivers, and so I reached out to GPA and Bill did mention that in his view both drivers sounded the same. Now, did he say this because they had more 8H-3 in stock and needed to clear them? Or did he genuinely believe in that statement I will not know for certain. BUT from my very short conversations with him, I have found him to be truthful and honest, so I can't see any reason to doubt him. As I said, I'm the newbie here, and only thing I can go by is what you, Bill and everyone on the board has been kind enough to share with me.
So, my decision was made because there was no concensus on this board about which driver was better technically. The only point that was moving me towards the E3 was the Alnico, and according to Bill, they were more expensive to produce and really didn't provide any measurable and audible benefits.
Now, from my own research, it was definitely not the case for the original Altecs. IF I was considering the Altecs, then I would have definitely gone with the Alnico versions. Given that GPA has been in the business for so long, with the experience that they have prior to setting up GPA, I can only deduce that considering that they still have access to Alnico magnets, that the 8H-3 is indeed an attempt by them to produce a driver that was made with a ferrite magnet that was at least equivalent if not better than the Alnico driver that they had. I can't imagine that they would produce an inferior driver (as the E2 came out before the 8H-3) when they still had stock of Alnico magnets. Until someone actualy publishes a side by side or A/B comparison between these two, we will not know for sure and the only words to go by are Bills.
Anyways, that's how I came to my conclusion, I am sure others may not do the same.
So GM, any opinions about my cab design? Or do you reckon it's a go?
Your thoughts are invaluable as always. As you know I was at a crossroads between the two drivers, and so I reached out to GPA and Bill did mention that in his view both drivers sounded the same. Now, did he say this because they had more 8H-3 in stock and needed to clear them? Or did he genuinely believe in that statement I will not know for certain. BUT from my very short conversations with him, I have found him to be truthful and honest, so I can't see any reason to doubt him. As I said, I'm the newbie here, and only thing I can go by is what you, Bill and everyone on the board has been kind enough to share with me.
So, my decision was made because there was no concensus on this board about which driver was better technically. The only point that was moving me towards the E3 was the Alnico, and according to Bill, they were more expensive to produce and really didn't provide any measurable and audible benefits.
Now, from my own research, it was definitely not the case for the original Altecs. IF I was considering the Altecs, then I would have definitely gone with the Alnico versions. Given that GPA has been in the business for so long, with the experience that they have prior to setting up GPA, I can only deduce that considering that they still have access to Alnico magnets, that the 8H-3 is indeed an attempt by them to produce a driver that was made with a ferrite magnet that was at least equivalent if not better than the Alnico driver that they had. I can't imagine that they would produce an inferior driver (as the E2 came out before the 8H-3) when they still had stock of Alnico magnets. Until someone actualy publishes a side by side or A/B comparison between these two, we will not know for sure and the only words to go by are Bills.
Anyways, that's how I came to my conclusion, I am sure others may not do the same.
So GM, any opinions about my cab design? Or do you reckon it's a go?
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I'm not one to question Bill, but the size doesn't strike me as anything like optimal for the S3 driver (if the published specifications are anything close to accurate). I'm going to suggest that you run some of your own simulations. At the very least, feed the numbers into the bass reflex calculator at mh-audio.nl before making any more plans.
Others will have more to say, but, yes, that's what I mean. Of course, I don't really understand the bracing layout in your diagram, so take my advice with a cup of salt.
Hah! You'll do fine. This kind of first-pass assessment with a web form is cookbook stuff. It'll take you five minutes -- tops.
Heck, run the numbers for the E while you're at it. You'll see what the folks on the thread were on about when they said that the drivers were going to sound different.
Ok, just did that, and it did take 5min, lol..... my port size is larger than the one recommended by the site. I have mine at 178.6 cm2 and recommended size is 143 cm2. Considering what you said about the 8H-3 and the 604s in general being lacking in bass, I would think I should stick with the GPA recommended size then?
Is there a way to calculate the location of the bassport?
Is there a way to calculate the location of the bassport?
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Flip a coin buff. Do it and don't second guess your choice. If you can't hear the speakers side by each, as much as I respect the opinions of those here, especially my ol' pal Mr M, they can't tell you what's best for you.
Buy an EQ. They're not expensive and they can solve a lot of what is not to your liking regardless of your choice.
Cheers.
Buy an EQ. They're not expensive and they can solve a lot of what is not to your liking regardless of your choice.
Cheers.
Amen. Perfection is a myth. This is a project with great potential, so enjoy it. Give it your best, work hard, and *enjoy it*.
Greets!
Interesting! We were discussing the pros/cons of AlNiCo Vs Ferrite, so when you made this statement I took it to just mean the motors, which I agree with until the drivers are sucking up some amps and again, only WRT the woofer.
We all hear the same, yet not so much, especially as we get older, so no way I ever question what folks hear less it becomes patently obvious they’re hearing impaired and since neither of us have auditioned either, much less side by side…….so you’re right, Bill’s thoughts hold sway, especially since he’s the designer of both.
Regardless, even if they were to sound identical to you when driven with a high quality SS front end, I still believe the E2 is a better choice overall for your musical preferences and especially once you swap to a high output impedance SET amp if the S3 and E2 published response plots are typical of all production units.
At this point, folks who either don’t notice a difference and/or are ambivalent about it tend to be tone deaf to some greater or lesser extent IME since there’s a synergy of sorts between AlNiCo and certain types of tube amp that’s hard to define. ‘Refined’/’liquid’ is about the best I can do.
Even then, this assumes that the magnets are made to the same specs as the originals, which may not be the case and there’s differences in the basic motor design of each to complicate matters, so hard to make any sort of accurate comparison beyond a blind A-B comparison.
Too many unknowns to really ‘nail down’ all the pros/cons from a purely technical POV to suit me, just tried to do match them up with your stated performance goals as best I could with what I have to work with combined with my varied experiences with Altec speaker products.
GM
WRT cab design, I’ve been openly critical of the vast majority of consumer speaker designs including Altec’s for going on 47 yrs now and GPA’s doesn’t fare any better.
Not that it’s a bad design, it’s not, just in comparing my way to Altec’s/GPA’s I prefer mine from both a technical and the subtle, but distinct, audible differences and judging by my ‘track record’ designing for others, I’m not the only one who hears them. The downside is mine tend to be somewhat larger since they are based on TL/horn design theory, so definitely not for everyone.
Bill may feel the same about mine [assuming he’s even familiar with them]. For sure, there’s some ‘old school’ speaker design posters here with ~ the same mindset who have made some general ‘absolute’ statements WRT certain aspects of speaker design that while not directly targeted towards me since there’s a few others that share a similar design mindset, it’s plain that they consider our way as too far off the ‘deep end’ to be seriously considered.
So, having chosen the driver based on its designer’s input, might as well follow it through with a functional equivalent to his suggested cab alignment since without a comparison between the two there's no way to compare them except that mine would play a bit lower and will require less internal damping for a given perceived 'smoothness'/'tightness' due to its ¼ WL TL pipe action doing a better job of damping the vent’s output and the lack of a notch in the upper mid-bass from the vent being too far from the bottom of the cab.
GM
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Make a double chamber
From what I briefly read, as GM was pointing at the special TL ...
BTW So that's the altec driver sorted out He he eh I see Cal's around
As some special "trademarks" of a TL which can be :" impedance smoothness"
; less int. reflections due to the "open" design
It can be also "modeled" as a double chamber reflex, with the first volume containing the driver very compact and filled with acoustic absorber; the duct is often the hole of the bulkhead . The second resonating chamber is tuned to a much lower frequency and it can be left with no acoustic fill.
From what I briefly read, as GM was pointing at the special TL ...
BTW So that's the altec driver sorted out He he eh I see Cal's around
As some special "trademarks" of a TL which can be :" impedance smoothness"
; less int. reflections due to the "open" designIt can be also "modeled" as a double chamber reflex, with the first volume containing the driver very compact and filled with acoustic absorber; the duct is often the hole of the bulkhead . The second resonating chamber is tuned to a much lower frequency and it can be left with no acoustic fill.
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