[Jed]

Does the OW1 have less distortion than the OW2 throughout its operating range due to a slightly different amount of coating on the dome?

What is the lowest X-over frequency the OW1 can handle LR4, yet still remain unstrained with low distortion?  

If I need a X-over point around 2K would you recommend a 1" dome tweeter?

Thank you,
Jed

[David Ellis]

Does the OW1 have less distortion than the OW2 throughout its operating range due to a slightly different amount of coating on the dome?

Yes, but the difference is extremely, extremely small.

What is the lowest X-over frequency the OW1 can handle LR4, yet still remain unstrained with low distortion?

With no ferrofluid, I wouldn't go lower than 2khz LR4.  Dennis Murphy managed a 2nd order crossover at 2500hz, but this was in a smaller 2-way that wouldn't see much spl.

If I need a X-over point around 2K would you recommend a 1" dome tweeter?

If you need to push more energy then I recommend a good tweeter suspension and ferrofluid.

I managed a 1600hz crossover with the OW1F and the W22.  I thought the tweeter would squak under the heavy load and higher spl.  It didn't.  I subsequently learned the Bud Fried used a single 10uf capacitor on his OW2F (with Ferrofuild) tweeters.  This seems absurd, but I can't argue with his commentary, or the results I heard in my experiment.  

Dave Ellis believes that a good tweeter suspension (good restoring force) throughout the X-Max range of a tweeter is far more important than size.  I believe these thoughts are reified by other folks.    Given the very good suspension of the SS9500, Mr. Short manages a crossover @1600hz in his speakers.  Sigfried Linkwitz manages a @1400hz in his Orion.  These may seem absurdly low, but with a good tweeter suspension, it works.  These are extremely good speakers with very well implemented designs.

Furthermore, not all ferrofluid applications are the same.  The importance of tight component tolerances cannot be overstated.  Not only to they couple the motor in superior fashion, they allow a very thin ferrofluid.   When carefully applied, there is very little impact on sound quality.  I sure can't hear the difference between the OW1 and OW1F.  Jeff Bagby agreed.

If I wanted to crossover something at 2khz or lower, I'd use an OW1F.  If you wanted a crossover under 1500hz, you really should use a 1" tweeter.

As a budget alternative, I really like the sound quality of the SEAS H1212 tweeter.  It has a very solid suspension too.  I believe this is the tweeter of choice for @ $25.

Summary... I believe that size does matter, but the tweeter suspension is more important.

Dave

[Jed]

I'm right in the middle between deciding on the OW1 versus OW1F.  The OW1F seems a bit more versatile, especially if I end up with a lower X-over.  The system will be OW1F or OW1, W15CH Excel with an open back enclosure, and W22EX for 300HZ and below.  The system was simulated with excellent results for a crossover around 2000-2100HZ for tweeter/midrange, but given the excursion limitations of the W22EX in a ported enclosure below 40HZ (max 100DB), I'm not sure I'll need the higher power handling of the OW1F in this system.  Comments?  And how long does it take to get the OW1F if they are not in stock?

Thanks,

Jed

[David Ellis]

I am certain you won't need the higher power handling of the OW1F.  I'd think the W15 should be viable to @3000hz, or 2500hz minimum.  However, if you do wish to cross @ 2000hz, the decision is a coin-flip.  The OW1F is a darn good tweeter and can really carry the mail.

Also, humbly, I can offer that as a bass unit the W22 is not a terrific driver.   IME, it's average at best.  

Phil Bamberg (BESL) conveyed the comments of a solid journal article published many years ago.  It conveyed and proved that phase plug drivers move less air past the voice coil and therefore dissipate heat worse than cones with a dust cap.  So, while the phase plug is great for midrange, it's not so good for bass.  I believe anyone comparing the W18 and SS8545 would convey the bass superiority of the SS8545.  I agree.  I'll also convey the Accuton C95 has better bass than the W18.

I know that a few commercial folks have used the W22 as a bass unit, and it looks extremely good.  However, given your desire to use the W15 in the midrange what I'd do is... use the Meniscus 838 for a bass driver.  It produces wonderfully detailed bass thanks to the 2" voice coil and dust cap.  Mark also has a bass specific unit with a larger dustcap that has a stiffer cone.  These 8" drivers don't look impressive, but the bass quality is very impressive - easily better than the W22 IMO.  The 838 would be my choice for a bass unit in @50 liters ported.  The crossover would be @150hz.  The design would approximate the Joseph Audio unit with the side firing 8" woofer.

@ 2 years ago it seemed reasonable tha a 2" voice coil would dissipate heat faster and produce better bass.  I experimented.  It does.

my 2c

[Jed]

Hi Dave,

The system you describe is definitely something worth looking into.  However, I already have the W22EXs and would like to give them a try.  I'm sure the Meniscus would be awesome, but in this system, with an open back midrange, I want to keep some of the lower frequencies off of the W15CH, too.  That is part of the reason why the 300HZ X-over between the midrange and the woofer was chosen, and also for ease of measuring the system for X-over development.  The sidefiring idea would require a huge inductor and be difficult to measure and get perfect.  

That said, I think perhaps adding a second W22EX and putting them in a 50L sealed box wired in series would give me some outstanding bass down to 50HZ F3 before room gain.  I could then add a subwoofer later and hi pass the W22s.  Or, and the option I'll probably go with is a single W22 ported in about 42-50 liters, and if I need deeper bass, add a separate subwoofer. I've literally been going in circles for 4 months on this system and have drawn out maybe 30 variations of cabinets etc.  Finally, I've decided on the Hiquphon, and will place an order soon.  If taking the W22 out of this system entirely, it opens up a whole world of new possiblities (L26, 8565 01, Meniscus, etc).

[David Ellis]

I'm sure the Meniscus would be awesome, but in this system, with an open back midrange

Yep, okay, I agree.  The lobing and cancellations would be very significant if the crossover was moved lower.  The in room response would dip as the open back midrange approached 150hz.

BTW, there is significant spl coming from the back of my basement 3-way - even after the midrange energy has traveled through 20" of insulation.  On the other hand from the front side of the speaker the impact of the open back midrange isn't audible.  My 2c is that an open back midrange really makes sense but for some reason it really isn't audible - despite the very obvious spl behind the midrange driver.

The sidefiring idea would require a huge inductor and be difficult to measure and get perfect

Yep, I agree here too.  Then, any low hz crossover makes matters difficult.  I also think the side firing idea is inferior, but have never a/b tested this.

Or, and the option I'll probably go with is a single W22 ported in about 42-50 liters, and if I need deeper bass, add a separate subwoofer

The issue isn't lack of W22 bass depth.  It's the bass snap and dynamics.  The W22 might be the cleanest 8" midrange available.  Certainly Sigfried Linkwitz chose wisely.  However, I don't think its the best 8" bass driver.   Howoever, since you already have the W22 drivers... using them is a wise decision    .

[DSK]

The issue isn't lack of W22 bass depth.  It's the bass snap and dynamics.  The W22 might be the cleanest 8" midrange available.  Certainly Sigfried Linkwitz chose wisely.  However, I don't think its the best 8" bass driver.   Howoever, since you already have the W22 drivers... using them is a wise decision    .

David, do you believe 2 x W22's per speaker would resolve these problems, or would a different 8" (or 10") be preferable?

[David Ellis]

2 voice coils will dissipate heat faster, but the cabinet will grow large.  I'd probably lean toward an L26/W26 sealed in @ 70liters.  These have a 2" voice coil and the same general makup as the W15.  The sonic character should mate easily.  I do like the Scanspeak bass quality, but the cones will generally flex.  

Hey, I have it!   You might be able to sweet-talk Jim Salk into selling you a couple drivers? These are dandy woofers with a 3" voice coil.

Dave

[Jed]

The issue isn't lack of W22 bass depth.  It's the bass snap and dynamics.  The W22 might be the cleanest 8" midrange available.  Certainly Sigfried Linkwitz chose wisely.  However, I don't think its the best 8" bass driver.   Howoever, since you already have the W22 drivers... using them is a wise decision    .

David, do you believe 2 x W22's per speaker would resolve these problems, or would a different 8" (or 10") be preferable?

You would gain about 3DB more headroom (103DB versus 100DB) versus a single W22 in a 50L box.  What system do you have in mind?  Mine is finalized with OW1 crossed around 2.3K 4th order, W15CH, and W22EX crossed 300HZ 2nd order with 50DB of attenuation off the resonance peaks for both mid and woofer.  Now have to finish up my boxes and get some measurements for the crossovers.

[DSK]

You would gain about 3DB more headroom (103DB versus 100DB) versus a single W22 in a 50L box.  What system do you have in mind?  Mine is finalized with OW1 crossed around 2.3K 4th order, W15CH, and W22EX crossed 300HZ 2nd order with 50DB of attenuation off the resonance peaks for both mid and woofer.  Now have to finish up my boxes and get some measurements for the crossovers.

Hi Jed,
After researching speaker design for a while I decided that I didn't have the time, funds or interest to spend several years building a variety of speakers to eventually get to where I want to be. Nor do I have the measurement equipment and facilities. So, I needed to find a high-end kit or commission someone to design speakers for me. I'm after a sealed 3-way (with F3 around 60hz or lower) that I will HP filter and use with my sealed sub. The Salk HT3 looked great but is not available in a kit (shipping fees to Australia of assembled speakers would be horrendous). Then I came across Rick Craig's (Selah) RC4 kit. I'm planning on building the sealed version of this speaker, but without the integrated subwoofer driver and amp. I would also have Rick adjust the HP filter down from 75hz to 60hz.

The RC4 uses Fountek CD3 ribbon, SEAS W15CY001 mag mid and 2 x SEAS W22EX mag woofers. I like the idea of matching the W15CY to the Fountek, rather than the larger W18 used in the Salk HT3. The dispersion match should be better and the xo freq can be raised to relieve the load on the ribbon and any potential harshness. Also the mag cone's breakup peak is an octave higher at 8500hz. So, the mids/highs should be as good as the HT3, perhaps even better. I'd like to keep the overall speaker sensitivity above 85db and min impedance above 3.5ohms. My 100w/ch amp will handle this and I don't want to have to change amps (I love my AKSA 100N+   ). Rick doesn't divulge his xo slopes or freqs, but I'm guessing around 300hz and 3khz.

David suggested the W26 or L26 or Jim's TC Sounds woofer. If I recall correctly, the TC's sensitivity is lower than my goal and the W26 is optimised for a vented box, but the L26 is optimised for a sealed box and could be suitable. Is my recollection correct on these issues? The L26 would have a lower F3 (handy but not critical when using wih my sealed sub) but how would the bass dynamics and quality compare to the 2 x W22's? I don't know enough to know whether the driver sensitivities allow the W15CY to be used with the L26? Also wondering what you prefer about the W15CH over the W15CY?

[tkp]

You would gain about 3DB more headroom (103DB versus 100DB) versus a single W22 in a 50L box.  What system do you have in mind?  Mine is finalized with OW1 crossed around 2.3K 4th order, W15CH, and W22EX crossed 300HZ 2nd order with 50DB of attenuation off the resonance peaks for both mid and woofer.  Now have to finish up my boxes and get some measurements for the crossovers.

Here you go

http://www.audiocircle.com/index.php?action=gallery;area=browse;album=233

W15CY was used instead of the W15CH and bass below 75 hz is handle by the 12" XLS.

[Jed]

Awesome speakers!  So, without the subs turned on how is the bass of those W22s?  I can't wait to hear mine.

[tkp]

Awesome speakers!  So, without the subs turned on how is the bass of those W22s?  I can't wait to hear mine.

Without the subwoofer turned on the bass is a bit thin and not as deep.  This was done per designed because the W22s was high pass at 75 hz in a sealed box.  I think it is best to keep the low bass out of the W22s and let the 12" XLS to take over.  The midbass was one of the best I have heard.  For reference, I also have a line array with 8 Fountek JP2, 10 W15s, dual XLS 12" per side.  The midbass of this speaker is almost as good.