Good poly mid-woofer (SEAS or Peerless)

[ch83575]

I am looking for a good poly mid-woofer, but I can not decide between the 830874 Peerless (6.5" Poly HDS) and the new P18RNXP that madisound lists from SEAS. I cant find much manufacturer data for the seas, and I cant find much DIY data on the Peerless so it makes them kind of hard to compare without having the units in hand. Zaph has measurements on the Seas, but not the Peerless and Mark K doesn't seem to have tested either yet. Is there any other source of data on these woofers that I am missing? If I must decide without a direct comparason I might lean toward the Peerless because there are many commercial speakers that I like very much that use this driver (the AVI and Linn top the list), but Zaph's measurements make the SEAS look pretty good too. Has anybody out there delt with both and might be able to give a recomendation?

As a side note, does anybody have experience using Madisounds return policy? I cant imagine that buying 2 sets of drivers with no intention of keeping both makes you very popular over there even if they would acomidate you. Any feelings on that?

Thanks,
Chad

[ch83575]

After reading my post I feel a little dumb... i just asked a "whats the best woofer in the world" kind of question. Let me try to be a little more specific. I am planing on a floor-standing 2 way, so enclusure volume is not much of an issue. I will probably be crossing to the Peerless HDS tweeter around 2-2.5k (as long as the woofers dont hold any suprises), perhapse even try to do a 2nd order, so a clean rolloff is important. I perfer sealed bass enclsures, but I dont think that either driver would produce much bass in such a configuration, and the SEAS Qts obviously makes it inapropriate for a sealed enclosure.

Hopefully that might help people interested in giving advise.

Thanks again,
Chad

[Taco]

I think that the Peerless HDS has a stiffer cone (which should provide better bass defenition). I do not know the Seas woofer,
but I heard the HDS, it's a good woofer but not that great.

The Seas woofer is pretty new (not listed at the Seas website), so I think there are not that many people around who actually used that woofer. My experience with Seas and Peerless are both good. In this case I think the HDS is a better choice for a 2-way. And you're right you don't get much extension in a closed box.

[MBK]

FWIW I can recommend the SS8543. This is a clear 6.5" poly cone, tested by Mark K and it really is a very clean sounding driver, as suggested by Mark K's data. Available from Madisound, this is where I bought mine.

[Taco]

The Scanspeak 8543, is a medicore unit compared to new offerings. I would not buy these anymore (Yes I used them myself). I think the mineral filled Audiotechnology, Dynaudio, Seas, and Peerless are better options if it has to be poly.

[MBK]

Hmm, honestly I bought the SS8543 because of very good measurement data (Mark K), compared to a _lot_ of woofers, and I do like them... In the absence of comparable measurement or implementation conditions it's going to be hard to tell which one out of a set of models is "better". Newer, or more technology laden, does not necessarily translate to "better" ; Zaph has a lot of surprises on his site where exotic materials (ceramic cones) or cherished design philosophies (ribbons) show serious problems, or no advantages at all, even compared to run of the mill offers...

Or let's put it this way - I'd choose a model where there is at least _some_ supporting test or data sheet data available that let you guess at likely performance, rather than choose on specs, novelty or subjective impression based on particular implementations.

OTOH much of the performance will come from the execution anyway, and smaller deviations in driver performance will be swamped out.

[mbutzkies]

MBK, Taco- I am interested in the 8543

Could you describe your subjective likes/dislikes in more detail? Other people have described this driver as a typical bland/boring poly cone, yet, MarkK tests show rather high sensitivity and reasonable CSD. Looking at markK tests, it performed near the top.

Second, since you both have first hand experience, can you tell me how you employed these midwoofers? 2way/3way -sealed/vented -XO points and slope.

Third, do you have any of your own measurements you could share? it seems the Fs is significantly more than the spec sheet. does it change significantly with burn-in, etc. Other people have said it has anemic bass.

If I would use this driver, I would use it as a sealed mid- 2nd butterworth ele 100~120hz+ 4th LR ele 2000hz

[Andy G]

I would hang for a short while, and see what "Zaph" thinks of these.

http://www.gr-research.com/drivers/m165x.shtm

He also has a few other 6.5's he is testing real soon.

[MBK]

Mbutzkies,

I use the 8543 in an open baffle, HP anywhere from 100 to 200 (have tried this range and not found much subjective differences, if x-o implemented well), up to 1700 Hz.

Likes: extremely clean sound, as evidenced by a simple sweep - no buzz, singsang etc, remember in Mark K's test there was virtually no high order HD. To my taste there is also plenty enough detail, definition of instruments in orchestras and their position etc. Since I do not use it in lower bass, I can't comment on that. A low HD might sound to some people as "anemic", these qualificatives are always problematic: how can bass be anemic if the FR plot is adjusted to be just like some other driver? etc. Note low Qts, if using a box and passive X-O definitely one would have to design it properly . AFAIK this driver was used in one of the Proac implementations.

Dislikes: none really, the breakup is not obviously audible (though I do use a notch filter around 1.8k to compensate for the rising response). The data sheet shows irregular off axis response >2k which was not too evident in my units. All things equal though I surely would like a flat response from 1-2k and not this resonant peak, however, 1- many other drivers have this "feature" as well, and 2- notching it out still gets me a textbook acoustic LR4 on axis. There is some off axis loss though at 1-2k, in open baffle ca. -3 dB.

Nearfield measurements attached,forget anything beyond 8", these are just room and baffle effects.

I have not bothered measuring t/s since I am using it far from resonance as a mid in a 3 way. The calculated 1st pole from data sheet should be ca. 135 Hz but appears to be at 100 Hz, that is after months of use, but then again this is mounted in a U-frame open baffle.

[MBK]

And here far-field, the falloff below 200 Hz is dipole rolloff, with off-axis behavior.