Dipole midbass - best of 3

[rick57]

I’m sure there are other great options, but here (Australia), to me, the shortlist for a dipole to cover 60 – 280 Hz (firmly set by other drivers to be used above & below) is:
- Peerless XLS 12,
- Lambda TD12S or
- Seas W22EX001 (used in the Orion over 120 - 1440 Hz).

At 280 Hz the XLS would need a steep slope (4th/ 6th) to avoid its first breakup, which begins at 500 Hz, with a quick 10 dB dip. But it’s a good price, and very low distortion. Nobody seems to use it for more than a sub, but why not?

I believe that the TD Lambda has only modest vent chuff as a dipole, which can be tamed. It’s low distortion, a faraday ring helps when you’re driving hard, should cover both ends of the range and is the most efficient (93 dB). But it’s twice the price.

The Seas would need extra EQ to counter its rolloff, being – 4 dB at 60 Hz, and is the least efficient (87 db), but the metal cone would give the most precision. It's about the same cost to me as the Lambda. Would it go an octave lower than it’s use in the Orion?

Over 60 – 280 Hz, for a diople possibly an unusual range – which would be best allround?

Thanks

[JohnL]

Interesting choices. I have W22s and TD12Ss in the house now, and personally I would say go with the Lambda for that range. I can't speak for the Peerless, I've heard them used for subs, but not up higher. The Lambdas are great, but a couple of caveats, I don't think they are as sensitive as they are spec'ed and they take a LONG time to break in.

I'm also going to toss a couple other choices in (and I haven't listened to these drivers, so this is just a guess). Seas makes a 10" mag (W25 or something) that might be nice, and Lambda (AE now) makes a dipole specific version of that driver that has a little more x-max and other stuff that supposedly makes it better as a dipole, might want to investigate that. That's my 2 cents.

John

[rick57]

> I have W22s and TD12Ss in the house now
You lucky man!

Yes a 10" Seas mag or the Lambda dipole would be better, but $ are limited.

Are both W22s and TD12Ss used as dipoles?,
- what do you prefer about the Lambda??

[Paul W]

Rick,
If I had to make a choice among the three, it would be the Lambda. IMO, the W22 would be the clear winner at 280Hz; the Peerless, perhaps, best at 60Hz. However, displacement of the W22 is too limited for a 60Hz dipole; the Peerless too close to breakup at 280Hz (don't underestimate the importance of low distortion at 280Hz). So, Lambda = best overall compromise.
Paul

my dipoles

[rick57]

Thanks Paul

BTW, you've done nice work!

[JohnL]

This is actually kind of funny bouncing between forums like this, but to answer your questions

Are both W22s and TD12Ss used as dipoles?,

No Neither, both are being used sealed.

- what do you prefer about the Lambda??

It's effortless, particularly in that range. I guess you are more xmax limited than power, but it seems like the more power I give it, the happier it is.

[sfdoddsy]

I have tried the W22 down to 60Hz but you will be fairly limited on volume unless you double or triple them up.

If you can get them in Oz, or have them shipped, the TC SOunds TC2+ is worth a serious look. The folk at www.htguide.com seem to think they will play much higher than your usual bass driver.

BTW, if you are planning on using these drivers in a H or W baffle, the sticking point may not be the driver but the resonance caused by the frame.

Cheers

Steve

[rick57]

Hi Steve

Yes, I was thinking that way about the W22 down to 60Hz.

And yes I know the resonance problem of the H & W baffle frames. Would go either U frame (a la NaO), or flat.

I agree the TC Sounds TC2+ is probably the best choice. On a quick search I can’t yet find a dealer – do you know any? Here in Oz??

Cheers

[rick57]

If we assume for a moment that the SL Phoenix with two XLS 12s has adequate Vd to cover down to about 30 Hz, to operate only down to 60 Hz – one octave higher - being dipole requires only one eighth the Vd.
So with the same size baffle, 60 Hz would require only a ‘quarter’ of an XLS. ie one XLS 12 would probably be comfortable for *most purposes.

However I agree with Steve: the newer 12 inch TC2+ with distortion levels low & in some cases lower than the XLS, could easily go lower.

Or, with it’s 54% higher Xmax and faraday ring, could it also, in a dipole:

- **handle transients better? and/ or

- have **less dynamic compression??


Thanks

(PS: I learnt from Thanh that there are only two TC Sounds dealers anywhere: O Audio and Splinter Sound, both US based).

[Pan]

For low use, TC2+ seems to be a killer, however above 100Hz the XLS is much better.

/Peter