Hi, Im looking to build a 2 way speaker similar to the Harbeth 30.2. I know the tweeter it uses and I know the woofer is proprietary and can not be purchased. What 8 inch woofer will provide that smooth forgiving sound? I assume it will need to be a plastic/composite cone. Suggestions are appreciated. TY.
Here’s a couple to get you going -
Vifa P21w is still available
Vifa P21W0-20-08 Woofer
Discovery 22w/8534 look easy to work with (there’s a 4 ohm version as well)
Scanspeak 22W/8534G00 Woofer - Discovery Range
Or the oddity that is the A26RE4, 10” and can be run without filter (as in the Seas a26 speaker).
SEAS A26RE4 H1411-08 Woofer, 25F-EW replacement, Dynaco A25
Vifa P21w is still available
Vifa P21W0-20-08 Woofer
Discovery 22w/8534 look easy to work with (there’s a 4 ohm version as well)
Scanspeak 22W/8534G00 Woofer - Discovery Range
Or the oddity that is the A26RE4, 10” and can be run without filter (as in the Seas a26 speaker).
SEAS A26RE4 H1411-08 Woofer, 25F-EW replacement, Dynaco A25
Harbeth use quite complicated crossovers. I think this one must be crossing around 3.5kHz mostly using natural rolloff from the RADIAL woofer.
This SEAS U22 seems to tick the right boxes:
H1659-08 U22REX/P-SL
Joachim Gerhard said he got it working with just a coil.
He also thought it went well with the DXT tweeter on just a capacitor!
As ever, endless crossover stuff can be done. But I always think if it works well on a simple filter, it'll work even better on a complicated one.
This SEAS U22 seems to tick the right boxes:
H1659-08 U22REX/P-SL
Joachim Gerhard said he got it working with just a coil.
He also thought it went well with the DXT tweeter on just a capacitor!
As ever, endless crossover stuff can be done. But I always think if it works well on a simple filter, it'll work even better on a complicated one.
I do believe it is this tweeter:
SEAS Excel T25CF-001 (E0006) Tweeter
I agree that the crossover looks complicated, not sure what they are doing there. Also it doesn't look like they use top quality parts lol.
SEAS Excel T25CF-001 (E0006) Tweeter
I agree that the crossover looks complicated, not sure what they are doing there. Also it doesn't look like they use top quality parts lol.
The Seas A26 looks very interesting. Also the SS is good alternative. I'll run sims of each and see what I get.
I had a Harbeth M20. I think their speakers nicely demonstrate that you don´t need overly fancy parts.
I guess their enclosure constructions are top notch though.
The M20 was a heavy little thing and wasn´t resonant in the slightest.
If I ever wanted a 2-way bookshelf, I´d go for the enlightenment from ampslab (theres plenty more of bookshelfs on that site), discovery from Troels Gravesen (or other) or maybe something from that site:
www.audioexcite.com >> Revelation Two – M4 WG
I guess their enclosure constructions are top notch though.
The M20 was a heavy little thing and wasn´t resonant in the slightest.
If I ever wanted a 2-way bookshelf, I´d go for the enlightenment from ampslab (theres plenty more of bookshelfs on that site), discovery from Troels Gravesen (or other) or maybe something from that site:
www.audioexcite.com >> Revelation Two – M4 WG
Yes, we like Mike Chua at Ampslab. But he is a low-order crossover man! Something to be said for it.
The recessed bass is a feature going back to the BBC/Rogers LS5/9.
Harbeth Monitor 30.2 40th Anniversary Edition loudspeaker | Stereophile.com
It's a negative polarity third order Butterworth idea, usually 90 degree phase. The recess allows you to take the crossover lower. They were good, the BBC engineers. Often used Zobels and impedance correction too.
BBC and Rogers Loudspeakers › BBC LS5/9
I think you'll have a lot of fun with this.
The recessed bass is a feature going back to the BBC/Rogers LS5/9.
Harbeth Monitor 30.2 40th Anniversary Edition loudspeaker | Stereophile.com
It's a negative polarity third order Butterworth idea, usually 90 degree phase. The recess allows you to take the crossover lower. They were good, the BBC engineers. Often used Zobels and impedance correction too.
BBC and Rogers Loudspeakers › BBC LS5/9
I think you'll have a lot of fun with this.
Harbeth makes a big deal about the Radius cone material vs poly and paper. Given that's proprietary, it leaves some other criteria for shortlisting:
8ohm non-metal cone
suiting SBB4 alignment for fb 40-45hz in box about 30l
flattish response out to XO of 2.4khz
So how about:
Peerless HDS 830869
Peerless NE225W-08
Scan 22W/8851
8ohm non-metal cone
suiting SBB4 alignment for fb 40-45hz in box about 30l
flattish response out to XO of 2.4khz
So how about:
Peerless HDS 830869
Peerless NE225W-08
Scan 22W/8851
@System7 pardon my ignorance but I just want to make sure I understand correctly. You are saying that the woofer is wired inverse polarity to the tweeter? And as far as the recess how does that allow you to take the crossover point lower (horn loaded effect?) Thanks I am the grass hopper 🙂
Oh Lor', and I thought you knew what you are doing! 😱
The reason the Woofer is recessed is that the difference in acoustic centres between the 8" and 1" drivers is normally about 5cm. As everybody should know 5cm is half a wavelength at 3kHz. Which means the tweeter is wired negative polarity to allow for this.
All happy days so far? Now if you want a lower crossover, you must recess the woofer a bit. Then you can explore the improved dispersion benefits of, say, a 2.5kHz crossover. A child of 10 can understand this, surely. 🙂
Next thing is you'll be asking for a crossover. I can see this dragging on a bit, frankly. 😕
The reason the Woofer is recessed is that the difference in acoustic centres between the 8" and 1" drivers is normally about 5cm. As everybody should know 5cm is half a wavelength at 3kHz. Which means the tweeter is wired negative polarity to allow for this.
All happy days so far? Now if you want a lower crossover, you must recess the woofer a bit. Then you can explore the improved dispersion benefits of, say, a 2.5kHz crossover. A child of 10 can understand this, surely. 🙂
Next thing is you'll be asking for a crossover. I can see this dragging on a bit, frankly. 😕
The smooth forgiving sound you look for more likely stems from the 8”-1” (or rather 3/4”) with quite high Xover frequency setup. Not from the cone material of the woofer. It is an effect of the power curve of the speaker system, which leads to relative low sound power in room at frequencies our ears are most sensitive.
That being said, any modern design with controlled directivity does a better job at that, I think. If you look for good 8”-waveguided 1” designs, you likely will find more value for money.
That being said, any modern design with controlled directivity does a better job at that, I think. If you look for good 8”-waveguided 1” designs, you likely will find more value for money.
I would also tend for the Seas A26RE4 as that driver has the same kind of qualities as the Harbeth woofers, but the crossover point will have to be lower with that one. More like 1.5 to 2Khz. The main thing about Harbeth speakers is drivers with no resonances in the passband and a mass loaded thin wall cabinet like the BBC LS3/5A. Crossover is tuned to each speaker to a propriate curve (that is not full flat, but sounds very good).
I was thinking on pairing a A26RE4 with the very smooth SB26ADC tweeter with crossover at 1800Hz to get a similar sounding speaker. I'm still working on the design, but the goal is to get a similar soundcolour, not a similar view. It won't be build anytime soon (to much other stuff in the pipeline first) but i think that combo or something similar could give you a similar sounding speaker.
The original tweeter in that speaker is a custom one made to specs specified by Harbeth by Seas, it's a variation on the one you mention but not exact the same. And you need to crossover it higher. To high to meet the A26RE4 in the right range. That's why i choose an other tweeter for that.
I was thinking on pairing a A26RE4 with the very smooth SB26ADC tweeter with crossover at 1800Hz to get a similar sounding speaker. I'm still working on the design, but the goal is to get a similar soundcolour, not a similar view. It won't be build anytime soon (to much other stuff in the pipeline first) but i think that combo or something similar could give you a similar sounding speaker.
The original tweeter in that speaker is a custom one made to specs specified by Harbeth by Seas, it's a variation on the one you mention but not exact the same. And you need to crossover it higher. To high to meet the A26RE4 in the right range. That's why i choose an other tweeter for that.
No doubt in my mind that Alan Shaw's Radial woofer is a very good plastic driver. Much more rigid than your typical floppy polycone, so less stored energy to smear the sound.
Wish lists are inevitable, but the 8" plus 1" idea can work well. I have built enough of them:
I did find the BBC Butterworth idea won a cigar. But am currently playing with 4th. order filters, just because I like trying out ideas.
I shall sim this one:
BBC and Rogers Loudspeakers › BBC LS5/9
See what it does. Should be interesting, because it's the basis of some very conservative Harbeth designs.
Wish lists are inevitable, but the 8" plus 1" idea can work well. I have built enough of them:
I did find the BBC Butterworth idea won a cigar. But am currently playing with 4th. order filters, just because I like trying out ideas.
I shall sim this one:
BBC and Rogers Loudspeakers › BBC LS5/9
See what it does. Should be interesting, because it's the basis of some very conservative Harbeth designs.
Ok so I embarrassed myself. I didn't see a reason to rub my nose in it as I don't recall ever being nasty to you. I respect your knowledge in this area, I think it was just my misinterpretation of what you said, but yes I do understand.
WRT to the alignment between the woofer and tweeter i am so conditioned to seeing the woofer pushed forward. I do understand the 1/2 wavelength rule. I do understand that cone woofers dispersion narrows at higher frequencies so a lower XO point can be helpful.
You can rest easy I am not asking you to do a crossover for me. This is conceptual right now so I can run some models. I just needed a starting point with some drivers. Generally I post sims and let people throw darts. Yes, it's embarrassing but I'd rather make the attempt.
Yes I am aware that the tweeter is modified for Harbeth so it is not what is available off the shelf 🙁 Your suggestion makes perfect sense. Thank you kindly for your input.
Thank you Markbakk for your suggestion. 8 in 2 way is exactly what I am after. Interesting that Harbeth makes a 3 way with a lower and upper tweeter. Im sticking with the 2 way though lol
Member
Joined 2009
Paid Member
So do they. As I recall, Harbeth run (or ran) the two tweeters off the same high pass, and if there was a low-pass on the larger of the two, the Stereophile measurements imply it wasn't doing a great deal.
Unless you can afford to stump up for AudioTechnology units, which are firmly in the 'if you have to ask...' category, or find a Tymphany built edition of the old Vifas, then as has been suggested, you're probably looking at the 8in Scan Discoveries or the Seas U22 as the nearest equivalents to what Harbeth have, with a Seas Excel tweeter, & a crossover lurking in the 2.5KHz region, give or take a few hundred Hz.
@Scottmoose, funds are not an issue (well Im not spending 2 grand on an individual driver lol) Those driver suggestions are fine I will look at them as well. 🙂 I just dont know where to get those in the US so I tend to stay with what is readily available.
Last edited:
Interesting, purpose of that? I dont know of any other manufacturer that does that...