New Driver Tests: SB Acoustics, Scans, Seas, and others

[Mark K]

Ha! Sorry I spaced out. I was thinking Seas W15 not SS.

Yes, you're right. Most/all the scans have a the first surround mode termination dip about 1k. I don't think it's very audible...I've got a pair of SS revelator 5"s but they are the midrange/midwoofers- 15M/4831g00. Just haven't had time to make a project out of them. Very nice though.

Never mind...

[Jed]

No problem Mark, I just got lazy and didn't type out the full model number. I usually think Seas when I hear 15W, too.

[FrancoB]

Jed,

Would you mind sharing the .zrd and .zma file for the 6600 tweeter?

It would be very helpful.

Cheers,

Franco

[Jed]

Jed,

Would you mind sharing the .zrd and .zma file for the 6600 tweeter?

It would be very helpful.

Cheers,

Franco

Unless you're using the exact same baffle and measuring conditions as me, the FRD file is useless. I'd recommend tracing Zaph's data on his website and extrapolating minimum phase data from that, then add in the baffle diffraction effects of your baffle using FR combining spreadsheet. Roman B. has a great website that documents this procedure here: www.rjbaudio.com.

Regards,

Jed

[FrancoB]

Jed,

I know that. I have dlr's files for this tweeter, but that file is 175K. I can't get a minimum phase from that one. It's simply too big.

Your file looks very clean. So, if it's not too much trouble?

Your help is highly appreciated.

Cheers,

Franco

[Jed]

Send me an email and I'll forward the info to you. Clearwavespeakers(at)gmail(dot)com

[Jed]

Battle of the 10s

Each has there own unique applications and characteristics. Deduce what you will. I'd be happy using any of these. Which I am.

Seas L26 85dbs

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Seas Excel W26 :E

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Dayton RS270s

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[Mazeroth]

The W26 and RS270 look great through the midrange! Too bad the RS270 has so much low-end distortion, compared to the Seas.

Thanks for the measurements. :T

[dlr]

Jed,

I know that. I have dlr's files for this tweeter, but that file is 175K. I can't get a minimum phase from that one. It's simply too big.

Your file looks very clean. So, if it's not too much trouble?

Your help is highly appreciated.

Cheers,

Franco

I was just perusing this thread. You should be able to use the Frequency Response Combiner to re-format, then generate the phase. You could also use the free version of Praxis to convert the file and to generate minimum-phase, I'm fairly certain of that.

Dave

[Jed]

TB W4 1337 in D4 box 88db

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Same conditions, CSS FR125

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CSS SDX7 in a 20L box:

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[b_force]

mm interesting the measurement of the SDX7.
This driver was also tested this month in the German magazine Hobby Hifi and it's very different.
Can you measure the SDX7 with 90dB?
Than I can make a better comparison.

[Jed]

mm interesting the measurement of the SDX7.
This driver was also tested this month in the German magazine Hobby Hifi and it's very different.
Can you measure the SDX7 with 90dB?
Than I can make a better comparison.

How so? Plus they don't convert to percentage like I do... so it might look different but actually be the same.

[b_force]

The Hobby Hifi is also in percent, but they tested at 85dB.
So it would be nice if you can test at 90dB. (is that possible ? )
I doubt that the peak at 900Hz will go to 3,2%, but it could be...

[Jed]

I doubt that the peak at 900Hz will go to 3,2%, but it could be...

Close. Good thing it is just 2nd order. This driver is usable to 800hz or so. It has a lot of Xmax and moves quite a bit of air for its size. I'd use it in a 3 way or crossed to a mid dome like the Alpair 5. My baffle for this test is 8" wide, so the FR has some diffraction even though the mic is around 8" on axis.

[b_force]

Thank you for the measurement.

This was the measurement in the Hobby hifi: (at 90dB)

Image not available

edit:

Looks like the SDX7 will perform worse if the volume is higher.
If you scale the image they look almost the same I think 8)

[oldbar]

First of all i am not very good at posting on forums that is why i mostly read and never hardly post.
Finally finished my boxes today I used a closed 33litre box for my seas L26 which F3b of around 53Hz.
The SB acoustic 5in in a 5.7 litre box for my midrange and the next few days i will start with the crossover.
I am also using the 27TBFCG .

[Jed]

First of all i am not very good at posting on forums that is why i mostly read and never hardly post.
Finally finished my boxes today I used a closed 33litre box for my seas L26 which F3b of around 53Hz.
The SB acoustic 5in in a 5.7 litre box for my midrange and the next few days i will start with the crossover.
I am also using the 27TBFCG .

I finished my M5Ws as well (XT25, SB 5, RS270s). Post some pics of your design and I'll do the same for mine this weekend. And welcome to the board!

Jed

[Jed]

I received a few emails about the SB 5" driver and how it might compare to the W4 1337 or Scan Speak. First of all, it is difficult to compare one driver to another driver when all the other drivers are different in the systems. That said, my feeling is the SB 5" is fabulous. Very detailed and works in an LR2 system, which is a plus. It doesn't do it like the Scans do, but pretty close and for 1/4 the cost. What the Scan's will get you is that goosebump factor. The SB 5" is VERY clean in my new M5W. Also, I'm really loving the XT25 when used LR2. Very detailed and smooth smooth smooth.

Onto the RS270s. This woofer is a steal at the price. Almost as good as the Seas W26 at under $90. It's a myth that you need a 120L box to make these sing in a ported box. Yes, my 60L cabinet will limit the low end, but the slam and impact from a 10" driver with 90db per 1 watt sensitivity is hard to ignore. The simulation says F3 around 40hz, but in room, with a low tuning frequency these woofers hit hard in the low end.

Jed

[oldbar]

I mounted my SB 5 in a 5.7 litre midrange cabinet and stuck with the 33 litre for the L26.
My comp has crashed and i lost the hard drive with all my work which i did not back up which was a big mistake.
I am actually impressed with the way the sb5 sounds and its detail.
Also I was thinking of maybe pulling out the L26 and redesigning my cabinets and trying the SB10"
The trouble is that it is the same price as a scan speak 25W8565-01 both roughly $299 each here.
My debate is is it worth buying for the price.

[Jed]

I mounted my SB 5 in a 5.7 litre midrange cabinet and stuck with the 33 litre for the L26.
My comp has crashed and i lost the hard drive with all my work which i did not back up which was a big mistake.
I am actually impressed with the way the sb5 sounds and its detail.
Also I was thinking of maybe pulling out the L26 and redesigning my cabinets and trying the SB10"
The trouble is that it is the same price as a scan speak 25W8565-01 both roughly $299 each here.
My debate is is it worth buying for the price.

The SB 10" didn't test so well in Voice Coil, although I'd like to test them myself.

[dlneubec]

Onto the RS270s. This woofer is a steal at the price. Almost as good as the Seas W26 at under $90. It's a myth that you need a 120L box to make these sing in a ported box. Yes, my 60L cabinet will limit the low end, but the slam and impact from a 10" driver with 90db per 1 watt sensitivity is hard to ignore. The simulation says F3 around 40hz, but in room, with a low tuning frequency these woofers hit hard in the low end.

Jed

That's good to hear Jed. Needing 120L/driver is a deal breaker for me, since I generally prefer smaller speakers. I've often thought about using this driver in a smaller volume, like 60-70 liters, but never pulled the trigger. I used the RS225 in a smaller than typical volume, with low tuning, in my SoundRounds and I thought it worked very well.

[Jonasz]

Jed: How low do you tune the RS270 in this 60 liter box?

[Paul Ebert]

I've done a little comparison of the RS270 and the RS225 in Unibox and, other than an additional 3 dB of sensitivity and the increase in volume needed by the RS270, they seem to come out the same.

My solution was to go with a pair of RS225s. This gives me more sensitivity than the RS270 and, presumably, lower distortion (at the cost of low impedance).

For those of you who have worked with the RS270 and the RS225, how would you compare them subjectively (i.e. soundwise)?

Also, any word on when the SB 4" might be released?

[Jed]

Jed: How low do you tune the RS270 in this 60 liter box?

Below 30hz tuning will get you an F3 of 36hz (unibox).

[Jed]

I've done a little
Also, any word on when the SB 4" might be released?

Someone said Jan. I haven't personally spoken to Madisound about it yet, so I can't confirm.

[Johnloudb]

Jed,

Have you done any listening to the RS270? I am using them in my IMF transmission line sub, as you might know. On test tones at low levels the KEF139B sounded considerably cleaner in the low end. Although, the RS270 wasn't that bad. I just attributed that to break-in. After all, I've never heard a new woofer or sub that sounded any good till it was significantly broken in.

Then I saw your distortion measurements. Not too good for a sub, with all the distortion in the low frequencies.

Anyway, I am hoping this will change with break-in. Most comments I've read on that driver are very positive even as a sub. If you have any experience listening to it, in one of your designs, I'd be interested in your comments.

Have you found that distortion measurements change at all with break-in?

[Johnloudb]

Each has there own unique applications and characteristics. Deduce what you will. I'd be happy using any of these. Which I am.

Looking more closely I see you have gave all the drivers positive marks. Thanks so much for your research! :T I need to get this crossover wired up and see how these subs work out for myself.

[Jed]

The RS270s is a wonderful driver for the money. It has more harmonic distortion below 50hz than the other drivers in the group, but not bad at all. The bass is just a bit "warmer" and less dry than the SEAS. Some may find it nice to listen to actually. I don't feel like I'm missing much information in the low end because it has a nice flat FR.

Jed

[Johnloudb]

Thanks Jed, that makes me feel better. I've got to get some work done and finish this crossover and hook them up to a real amp, not just a T-amp. Even with the T amp I got some pretty clean bass, just a tad warm. But, that will hopefully improve once I get them broken in.

[cotdt]

Hmm I've just been playing with the SB Acoustics 5" driver in a preliminary 2-way crossover. The low end doesn't sound as clean as my Scanspeak 15W or Peerless Exclusives. Seems like a pretty average driver to me. It's a pretty average motor but with a shorting ring to reduce distortion as the frequency goes up, just like the Vifa XG18/XT18 drivers. At higher outputs (I listen to music LOUD) the driver becomes a sort of distortion generator.

[Jed]

Hmm I've just been playing with the SB Acoustics 5" driver in a preliminary 2-way crossover. The low end doesn't sound as clean as my Scanspeak 15W or Peerless Exclusives. Seems like a pretty average driver to me. It's a pretty average motor but with a shorting ring to reduce distortion as the frequency goes up, just like the Vifa XG18/XT18 drivers. At higher outputs (I listen to music LOUD) the driver becomes a sort of distortion generator.

Who ever said it was as clean as a Scan Speak on the low end? I'm using it in a 3-way right now and it sounds great for the money, but not as clean as Scan 15W in the mids. It needs a bit of work to shape the FR though. How are you handling the hump around 800-1k and the cone breakup in the treble? Could you post a plot of your FR so we can see what you are hearing?

I agree with Zaph that the SB Acoustics 5" is a good value.

[jkrutke]

Hmm I've just been playing with the SB Acoustics 5" driver in a preliminary 2-way crossover. The low end doesn't sound as clean as my Scanspeak 15W or Peerless Exclusives. Seems like a pretty average driver to me. It's a pretty average motor but with a shorting ring to reduce distortion as the frequency goes up, just like the Vifa XG18/XT18 drivers. At higher outputs (I listen to music LOUD) the driver becomes a sort of distortion generator.

The XG/XT18 has an undercut pole piece while the SB 5" doesn't. All things considered, the XG/XT woofers have great motors but I think they have increasing low end distortion due to other factors such as suspension non-linearities and limited Xmax. Hard to say for sure without a full Klippel run on them to separate the issues.

Here's the motor of the SB woofer. It's not a shorting "ring" so much as a strategically formed sleeve. It continues above the gap just the right amount so that it works with the coil length to give us a flat Le(x) curve. The only thing that could possibly improve it is an undercut, and even then not much, because the sleeve partially compensates for that. I'd still call it a great motor though, very far above average. I'm working on a page to post a bunch of Le(x) plots. When it's posted, this woofer is one of them.

[dlr]

That looks very much like the Scan-Speak pole-piece cap. The patents must have expired. Here's a 13m/8640 (almost the same motor as in the 13m/8636 as well):



OT: The 13m/8640 has a bumped back plate, the 8636 does not. I'm not sure why they make them differently. I suppose that the 8640 was to be able to be crossed a bit lower. Interest in these drivers fell off before there was so much attention paid to motor design and distortion as these motors are probably nearly the equal to any others in the midrange category today. The one thing I should say is that I don't know if it's undercut or not.

One issue is the shallow design lacking a very open back, but it's for just this reason that I like them. The acoustic offset is minimal. I can deal with the lowish sensitivity (not an issue for an MTM), but for an MT that's still an issue with many newer pure midranges today.

Dave

[Jed]

Thanks for the pics gentlemen. Interesting to note the engineers for SB Acoustics used to work for Scan Speak. Perhaps that explains the similar motor design?

[A9X]

Hmm I've just been playing with the SB Acoustics 5" driver in a preliminary 2-way crossover. The low end doesn't sound as clean as my Scanspeak 15W or Peerless Exclusives. Seems like a pretty average driver to me. It's a pretty average motor but with a shorting ring to reduce distortion as the frequency goes up, just like the Vifa XG18/XT18 drivers. At higher outputs (I listen to music LOUD) the driver becomes a sort of distortion generator.

If you listen loud, why are you even bothering with a 5" 2 way? Get a driver that will move some air at LF and make it a 3 way.

[jkrutke]

Thanks for the pics gentlemen. Interesting to note the engineers for SB Acoustics used to work for Scan Speak. Perhaps that explains the similar motor design?

Hmmm, maybe, But Scan-Speak's arch enemy (Usher) has the same formed sleeve. I know a lot of the cheaper drivers that use a sleeve only have a "cap" that doesn't extend above the pole piece. I think the new Fountek FW168 is like that.

Good motors are easy and these days I don't think enough attention is paid to the soft parts. That's kind of where the SB's fall short, IMHO. We'll see what those same designers can do with the ScAR drivers. They did design the Revelators after all, drivers with pretty much the best cone and suspension. I've been promised a test sample when the ScAR drivers come out.

[Jed]

Hmmm, maybe, But Scan-Speak's arch enemy (Usher) has the same formed sleeve. I know a lot of the cheaper drivers that use a sleeve only have a "cap" that doesn't extend above the pole piece. I think the new Fountek FW168 is like that.

Good motors are easy and these days I don't think enough attention is paid to the soft parts. That's kind of where the SB's fall short, IMHO. We'll see what those same designers can do with the ScAR drivers. They did design the Revelators after all, drivers with pretty much the best cone and suspension. I've been promised a test sample when the ScAR drivers come out.

Yeah, I was talking to the guys at Madisound about the SCAR driver. They have one sample for review right now. Not sure they would let it out for testing yet. They said it has an unusual composite cone, and it's a nonstandard size between the typical 5-7". They said it's going to be priced around Revelator/Illuminators.

[Jim Holtz]

Who ever said it was as clean as a Scan Speak on the low end? I'm using it in a 3-way right now and it sounds great for the money, but not as clean as Scan 15W in the mids. It needs a bit of work to shape the FR though. How are you handling the hump around 800-1k and the cone breakup in the treble? Could you post a plot of your FR so we can see what you are hearing?

I agree with Zaph that the SB Acoustics 5" is a good value.

Hi Jed,

I've been following your tests with great interest. Comparing the distortion graphs on Zaph's website and your tests, the SB looks like it should be equally as clean and clear sounding as the Revelator. What do you thinks sets the drivers apart sound quality wise?

BTW, I really enjoy the tests you, Zaph and Augiepro have done.

Jim

[jkrutke]

What do you thinks sets the drivers apart sound quality wise?

In the bass, probably suspension non-linearities, particularly from the spider. If you've seen the spider from a Revelator, it's truly a work of art. It's got a self damping profile. I was sad to see that it was not used in the new Illuminators. They just have a normal ribbed spider.

Yeah, I was talking to the guys at Madisound about the SCAR driver. They have one sample for review right now. Not sure they would let it out for testing yet. They said it has an unusual composite cone, and it's a nonstandard size between the typical 5-7". They said it's going to be priced around Revelator/Illuminators.

FYI, cross section views (small and blurry, sorry) of the ScAR drivers. The woofer is similar to the small SB's but undercut and now has a neo motor. Undercut drivers always seem to have a 2 piece T-yoke due to the machining operation on the polepiece. I think this is pretty much the same configuration as the Revelators and the Ushers, though I'm not 100% sure. Never had the balls to cut them open.

[Jed]

Hi Jed,

I've been following your tests with great interest. Comparing the distortion graphs on Zaph's website and your tests, the SB looks like it should be equally as clean and clear sounding as the Revelator. What do you thinks sets the drivers apart sound quality wise?

BTW, I really enjoy the tests you, Zaph and Augiepro have done.

Jim

Thanks Jim. The Revelator 15W non coated driver I tested in this thread has an unbelievably flat and extended top end with a minor dip at 1k and a peak at 840hz. The SB acoustics driver, in the same cabinet (my kit called the M5W), has more of a plateau at 800hz-1k and peaking at the top end. The Revelator driver allowed me to notch out the narrow band peak with no problem at all, but SB 5" driver's peaks are a bit more of an issue to deal with. The SB5 also has a lot of cone breakup at it's top end, and as John K. pointed out, has a cone that isn't as well damped. Therefore, in my Duet10ss design (uses the scan mid), there are fewer parts in the crossover to hit the LR2 targets. The resulting sound is clean clean clean. The Revelator seems to have a better top end (greater dispersion), therefore the clearer and smoother sounding highs. I have not tried the SB 5" with a Scan Air Circ tweeter which is better than the XT25 (XT25 is used in my M5W kit), so it's tough to really be completely objective with my listening impressions, I'll admit.

[Jed]

Never had the balls to cut them open.

I wonder how many years of bad kharma one would get for killing one of those drivers. :B

[augerpro]

Jed I wonder if a cone/surround treatment would be worth while on the SB? I've been meaning to ask John Janowitz what he uses on the AE drivers...

Is Scar a new brand?

I wonder how the new Vifa's that look similar to the Illuminators will turn out. Anyone have an update on them?

[dlr]

Jed I wonder if a cone/surround treatment would be worth while on the SB?

I would say yes. I made a quick test on an SB17 to see if it reacted to some distributed mass and it did (it was a reversible test). They should respond similarly to the tweak I made to the Insignia woofer, leveling the shelf area a bit. When I get some time (been in short supply for a while) I may buy an SB15 just to test this. That is irreversible, though. I suspect that the reason it's not applied by OEMs in many cases is the cost and difficulty of repeatability.

Dave

[Mark K]

I'm curious about the SB 5". I've got the pair that Zaph loaned me and we'll see if they exhibit the same problem as the SB 7 which is some higher order distortion which, I think is actually wind noise/resonance within the motor. It mars an otherwise very stellar performer in the nonlinear distortion range. (Will post all next week.)

[dlneubec]

Jed I wonder if a cone/surround treatment would be worth while on the SB? I've been meaning to ask John Janowitz what he uses on the AE drivers...

Is Scar a new brand?

I wonder how the new Vifa's that look similar to the Illuminators will turn out. Anyone have an update on them?

Speaking of John, he has a 8mm xmax/91db Lambda TD6.5H in the works. He is supposed to be sending a prototype pair to Jeff Bagby very soon that I'm supposed to be measuring. I believe the intent is to compete at the ScanSpeak level. If he can make something that rivals the performance of the TD12H that I'm using in the BaSSlines, it should be well worth consideration for higher end designs.

IIRC, Scar is the high end driver group created by the guys doing the SB Acoustics drivers. The SB drivers were supposed to be more entry level and the Scar at the ScanSpeak Revelator level.