Scan-Speak 15W/4524T-02 & D2604/8320-02 "Limited Edition" Combo

[JonMarsh]

No. Not in my opinion. Now, in the past, I have liked some other short throw ScanSpeak tweeters. And if you mounted it with a good waveguide design, then that could make the difference and reduce the excursion loading. But for a direct radiator setup in three way, what advantage does this part have over an RS28F? with it's 1mm Xmas? Versus 0.1mm for the Scanspeak? Is it flatter, smoother, lower distortion? Maybe it's prettier, as it looks like it's big brothers, sort of like a low buck 6600.

Now, here's the deal- it's a pretty good match to the 5" Scanspeak, because they're both dynamic range limited and they'll both get into trouble at about the same point. This is a common thing for systems in this price point- the new Elac Andrew Jone's Un-iFi 5" UB5 three way with a concentric midrange/tweeter has the same kind of issue- sounds quite nice up to about 90-92 dB, then gets pretty shouty all over. It runs into it's distortion limits. Nothing should be surprising about that, for a system that size, but people have sort of gotten used to Andrew Jones being able to pull off miracles.

The Ardent is designed to play to 100dB as clearly as possible, and that means a tweeter with some reserves and low distortion when you push it. If I ever design a "Budget" Ardent, it will have the same dynamic range, or as close as I can make it, to the original. The D2604/832002 wouldn't make the grade.

[Wayman]

Ok, got it! More to making soup than bouillon cubes!

I suppose many small speakers are designed for lower volume listening in condos & apts.

Cheers, Wayne

[NyxOne]

Well, I'm a lot later getting back to this than I expected, but between issues and problems in the personal life and at work, audio has been a distant 3rd.

First, I have done some driver analysis and modeling. The 15W/4524 is a quirky little guy, but I think I have some useful suggestions. Due to 4 ohm and general build, the sensitivity is fairly high, and the Qes and Qts fairly low, along with a reasonable Fs. But it doesn't model well in larger enclosures (say, 15L), will get pretty peaky with a reflex port. What does work fairly well is about 8L net, tuned to about 45 Hz. Two inch ID is fine as regards peak port velocity. But, with that sizer enclosure, you still need a port about 30 cm long to get that tuning- that's bit over 10"!! Going to probably need something creative like a bottom slot load port.

If you use crossover parts that keeps the net resistance on the woofer circuit around 1 ohm or below, you'll wind up with a curve similar to this:

I went with this route (7L / 45hz tuning) and although the bass is there it's only "OK"... There is definitely a lack of punch or presence in the bass department. I guessed that they would greatly benefit from a subwoofer... as a lot of smaller system do.

OTOH, this is a small speaker, and sometimes some psychoacoustic engineering is desired, or maybe,, just plain psycho. :B

In this case, I would engineer the crossover for a net DCR of 2 ohms; it will drop the sensitivity a bit more, but it will also give you a BBC LS3/5A lift, and subjectively a more satisfying bottom end. All smoke and mirrors, but what you do in the privacy of your own home is quite up to you...





Particularly if you listen to pop and rock and roll, I think one will prefer this alignment from a small speaker.


I'm preparing to make test baffles today- hope to finish that soon.

I had considered going that route but using an undersized inductor with a DCR around 1.5ohm but I chickened out at the last minute... When Solen's send them back to me in February I'll try it out.

Aside from the bass/midbass bump and the loss of efficiency is there any other known draw back of using high DCR crossover ?

Chuck

[JonMarsh]

Wounded ego? Wasting valuable planetary copper resources?

I'm doing another similar system design like this, different drivers, and using air core inductors for that reason. No cheap iron core to worry about, and easy to get the extra resistance without using a resistor! :B

BTW, that is most definitely 8L NET! not gross... the magnets on those little woofers are pretty big...

[NyxOne]

Wounded ego? Wasting valuable planetary copper resources?

I'm doing another similar system design like this, different drivers, and using air core inductors for that reason. No cheap iron core to worry about, and easy to get the extra resistance without using a resistor! :B

BTW, that is most definitely 8L NET! not gross... the magnets on those little woofers are pretty big...

I can live with a bruised EGO!

I'll definitely try it when they get back home!

Thanks
Chuck

[JonMarsh]

Update for Dan- test baffles are being cut and routed this afternoon. about half way through that. Needed to repair HT setup (non functioning center channel) for GF first.

I hope to be doing testing tomorrow; otherwise, latest next weekend.

[technodanvan]

Thanks for the update Jon. I've been so busy I haven't even remembered to check in for the last week or so. Probably not going to change for the next month. Somehow I'm supposed to design and make a desk for my wife in the period too!

Interesting results so far. Looking forward to seeing a second set of box measurements.

[JonMarsh]

All the baffle and cabinet work were finished by late yesterday afternoon- GF is going to a BDAY party for one of her friends next Saturday afternoon, so that will be the ideal time to setup and measure... have a few others things collected to measure then, too. Baffles checked against drivers, also.

Good luck with your desk project- that's going to be a fair amount of work, but I'm sure you know that! :B

[JonMarsh]

I managed to fit in the final assembly and testing this weekend, but ran out of time for posting- life is hectic these days.


The testing was done in some PE 8L cabinet's I bought for small driver testing and analysis- and who knows, at some point I may be able to build a system for my man cave with them!




To facilitate testing and possible crossover development, I used the dual post plates from PE for connections- both drivers can be tested at the same time. Enclosure was stuffed with long fiber wool, fairly densely.


The SS drivers themselves are very nice looking, and the boxes and packing are of exceptional quality- much better than the older more expensive Revelator drivers, which come with much less adequate cardboard packing. They fit well in the enclosure baffle, note that I did back side bevel the woofer opening, AND I used the larger diameter target circle outside the built in gasket, because in my opinion that results in too much rear masking.




The 15W polars are up first- measured at 0 degrees, 15, 30, 45, and 60. I'll prepare minimum phase FRD files of each, and suggest using them together in a tool that can combine for power response in the crossover development like VituixCAD.




Things look pretty nice here, and a crossover point as high as 3kHz could be possible, though I'd really recommend staying down around 2500Hz or less to make managing the time offset easier.


Distortion products are very good for this type of driver, too... this is a very nice little motor, and cone behavior appears quite well controlled on these samples.





The tweeter frequency response looks nice, for this particular series, with this voice coil design, the overall balance is pretty smooth. Some cabinet diffraction is evident around 3 kHz, and their is some peaking of the on axis response, which is pretty common for this kind of soft dome. Response is measured out to 40kHz.




The measured distortion performance was a bit odd, as it seems the reverse of typical ScanSpeak tweeter behavior, with lower 2nd harmonic and higher 3rd harmonic. I can sort of understand the 3 harmonic because of the very low Xmax, 0.1mm; this is due to this tweeter having a very long voice coil and not much gap left over. this may account for the relatively low 2nd order, if it's well centered and working in a more symmetric use of the gap flux.




Given the low Xmax, but also the lower overall SPL capability of a combination like this, one can probably get away with a 2kHz crossover with a reasonable order (like my funny LR3). Otherwise, I'd likely suggest 2500 to 3kHz, if you want to go with LR2.

I have the impedance curves, too, and will post that info soon.

Something to keep in mind with smaller systems like this is having reasonable SPL expectations- it's like the small Elac three way with the concentric mid/tweeter driver and a 5" woofer; things are pretty nice up to about 89-90 dB, but above that distortion rapidly rises, and things get a bit shouty and PA like.

[JonMarsh]

One comment- given the measured distortion performance of these woofers, if they weren't so "limited" in availability, I'd say a small MTM in say, a 22L enclosure, with a Transducer Lab tweeter might be a very interesting little system.

If I wanted to be mean, I would go to Madisound and buy out all that they have of the 15W...

[NyxOne]

One comment- given the measured distortion performance of these woofers, if they weren't so "limited" in availability, I'd say a small MTM in say, a 22L enclosure, with a Transducer Lab tweeter might be a very interesting little system.

If I wanted to be mean, I would go to Madisound and buy out all that they have of the 15W...

So I'm guessing you're impressed by the woofer but not so much by the tweeter?

Nice set of curves BTW, much better than mine... I pretty sure something must be wrong with my setup because my distortion reading resemble in no way yours! I've been having doubt about my old amplifier, I guessed it's time to send it to the repair shop!

How much acoustics offset did you get between drivers ? I got 32mm with both drivers recessed. It was much more than I had anticipated and had to tilt the enclosure by 6-7 degree in order to facilitate the crossover design.

Great work and thanks for posting,
Chuck

[technodanvan]

32mm? That can't be right...right?

Thanks for the hard work John. I'll probably stick with the original 2-way plan. As much as I'm interested in your MTM suggestion I don't really want to be stuck with another set of leftover tweeters I don't know what to do with! Plus these may well sit on my work desk, so overall output should not be an issue. I may need to try some measurements sitting on a desk near a wall to see how much that will affect the low end though. If it's "good enough" I'll probably avoid using a slotted port like you previously suggested.

Edit: Though I guess I could just buy up another set or two of the drivers for future use...

[NyxOne]

32mm? That can't be right...right?

Maybe I've goofed up there too but that's what I got. I was expecting something in the 15-18mm range... With a 6-7 degree the offset is moved down to around 16-17mm.

I used the old three points measurement to determine the offset. Eg : Measure the tweeter, measure the woofer, measure the woofer and tweeter connected in parallel.
Setup a project in lspCAD with only the tweeter and woofer (no xo), use the woofer and tweeter in parallel as target and fiddle with the woofer Z position to guess the acoustics offset.

Note : 32mm is 1.26 inch!

Chuck

[JonMarsh]

I think that is about the right value- people often underestimate that, and the method you describe is the gold standard. And I can get the direct time offset in Fuzzmeasure pretty well, but it seems to always correlate with the LspCAD method.

[JonMarsh]

They've been dropped off at UPS, going out on Ground shipping Monday morning. PM me if you'd like the tracking number.

[NyxOne]

May I know how you perform your measurements ? Drive level, distance, etc ? I'm interessed in your procedure and setup!

Chuck

[JonMarsh]

I'll do a short write up for you soon- having a really bonkers week at work, both planned and unplanned activities. not much left in the schedule after 12 hour days. Today is starting in a bout 10 minutes- it's the problem with working with East Coast and European teams- I have to live on their time zone in the AM, and CA in the afternoon.

[NyxOne]

I'll do a short write up for you soon- having a really bonkers week at work, both planned and unplanned activities. not much left in the schedule after 12 hour days. Today is starting in a bout 10 minutes- it's the problem with working with East Coast and European teams- I have to live on their time zone in the AM, and CA in the afternoon.

Can't say I feel your pain because I don't think I could grasp the amount of work and pressure you seem to be under in a average week! I've been around long enough to know that you're a workhorse so when you say you're having a tough week It's easy to understand that you're really having a ROUGH one!

Take your time, I'm not a in a hurry and I don't want to put pressure on you in any way!

Chuck

[djkest]

Man, I thought this woofer looked excellent, as the bottom of a small 2-way. The tweeter I could do without. However there are just so many quirks I find it hard to see where it would be ideal. Decently high sensitivity, and potentially smooth midrange, but there are problems with that too. So in the end, probably a pass. It looks really cool though. And Madisound dropped the price to $59.

[JonMarsh]

So they still have some left? Solen did their contest and were completely sold out in the first couple of weeks...

Really, that's an awfully flat, smooth response for a small SS midwoofer- none of the break and rise stuff after an impedance blip! Just combine them in an MTM with a TL tweeter or something similar that is happily doing some excursion down to below 2K, and all should be well.... to do it cheap, I'd go with an RS28a in a waveguide.

[Zvu]

Madisound still offers it - and for 55 bucks each. Just sayin'

https://www.madisoundspeakerstore.com/approx-5-woofers/scanspeak-15w/4524t02-limited-edition-5-fiberglass-cone-woofer/

And while in USA things look good, in UK it's double the cost.

http://www.falconacoustics.co.uk/drive-units-1/scanspeak-speakers-drive-units/scanspeak-15w-4524t02-midwoofer-limited-edition-discovery-range.html

USD=1.31xGBP

It's actually 20 bucks cheaper to order them from USA and pay for cross Atlantic shipping from Wisconsin than to buy them from FalconAcoustics.

[fish fingers]

Falcon have these on special.

Sent from my SM-G950F using Tapatalk

[JonMarsh]

well, the consumer/builder economy strikes again- for $55 each, and free shipping and no tax, I figure I have to put my money where my mouth is, so four are on the way to me now.

In an MTM with TL ceramic tweeter, the woofer and tweeter cost will be pretty close... of course, I probably won't have time to measure, design, and build these until late 2019 the way things are looking and going...

Just another set going in the driver bank for now...

[technodanvan]

Just another set going in the driver bank for now...

Hey, at least we tried to prevent this from happening. :P

I still haven't gotten around to doing anything with mine. Might grab another pair or two just...because? 8O

By the way, did you ever post FRD/ZMA files?

[JonMarsh]

I can't really post them on HTguide (no means?) but PM me/email me and I'll send them.

I'm thinking I may even try a Monacor waveguide with this, and I have some Wavecor 185 PR's lurking in the driver bank that I got a good deal on this year but I think they may be discontinued.

[phamtuongdk]

Got an email from Madisound marketing these two units:

ScanSpeak Limited Edition D2604/8320-02 1" Textile Dome Tweeter

https://www.madisoundspeakerstore.com/soft-dome-tweeters-scanspeak/scanspeak-limited-edition-d2604/832002-1-textile-dome-tweeter/

ScanSpeak 15W/4524T-02 Limited Edition 5.5" Fiberglass Cone Woofer

https://www.madisoundspeakerstore.com/approx-5-woofers/scanspeak-15w/4524t02-limited-edition-5-fiberglass-cone-woofer/

$288.60 USD for a full kit of two drivers and two tweeters. Supposedly only a few hundred sets will be available, but I don't know if that's per store or what.

I still haven't done any measurements on the desktop speakers I started for my wife three years ago, so I hadn't really been thinking about starting another project. For some reason I like the look of these. I did a little research but can't seem to find any recommended designs from Scan-Speak, which I think is weird since they are clearly meant to complement each other.

Any thoughts? I might just grab them to play around with next year, but I probably should finish my other project first! Might grab a pair or two of these as well, just because you never know what comes up...

Seas Prestige 27TFFNC/C H1482-06 1" Soft Dome Tweeter
https://www.madisoundspeakerstore.com/deal_of_the_day

Can you share me the crossover scheme of this kit?. Thanks !

[phamtuongdk]

Can you share me the crossover scheme of this kit?. Thanks !

[JonMarsh]

There is no crossover scheme- these were just sold by Scanspeak through Solen, Madison, and others as a special driver set to design with.

Between work and my GF's cancer I have not had time for any speaker work in 2017- heck, I didn't even remember that I bought a couple of pairs of these until reading this post. GF started hospice at home two weeks ago- still no time for audio, so these won't likely get any attention from me in the next six to 12 months. Way to much other stuff to cope with.

[JonMarsh]

Yup, four of the woofers, but none of the tweeters. No idea, except that I'm kind of in love with Transducer labs tweeters for some of the next projects.

But they are in stock at Madison. Hmmm.

[Dave Bullet]

But they are in stock at Madison. Hmmm.

:smackbutt: :smackbutt: :smackbutt:

[fish fingers]

Jon if you have time, check out Solen's current promotions.. ie tweeters..

Best wishes to your GF and to you

Sent from my SM-G950F using Tapatalk

[JonMarsh]

:smackbutt: :smackbutt: :smackbutt:

Pesky autocorrect. PITA.

Madisound. this time...

[JonMarsh]

Jon if you have time, check out Solen's current promotions.. ie tweeters..

Best wishes to your GF and to you

Sent from my SM-G950F using Tapatalk

Well, that's interesting that they have so many... and the price, especially in Canadian dollars is attractive enough to almost offset the shipping cost premium for Canada. Usually I buy from Solen when they have stuff Madisound or HiFi Collective in the UK doesn't have available or in stock.

Hmmm. Hmmm. Should I resit, or let the Dark side take over? :W

Tweeters from Solen, woofers from Madisound. Might be just the think for future surround sound satellites.

Thanks for the kind wishes, unfortunately the last two weeks haven't gone well- have a plan to address the issues causing the current decline, have to see if they work out. Will probably be getting a motorized recline adjustable hospital bed in soon, as discussed last week. and maybe a motorized recliner in the family room. She's gone from being able to walk with Masha and I morning and evening two weeks ago, to only occasionally a week ago, to not at all since mid week. That really disappoints her, because that time with Masha (our Siberian Husky) means a lot to her...

[Face]

Very sorry to hear it, Jon.

Sent from my SM-G935V using Tapatalk

[Carl V]

Very sorry to hear this.
Been there in the recent past...
Best of luck to you both, its a struggle.

[JonMarsh]

Thanks for the sympathy, guys. Nothing prepares you for this kind of stuff.

I did order the tweeters, though, from Solen. Thanks Fish Fingers.

[fish fingers]

Yes nothing does, but somehow you know to stay strong. Had a similar situation w my dad

Glad you got those tweets. I must order a few pairs of those little wavecor's today.