Interesting Drivers

[Juhazi]

Oh, it is the IEC 268-5 test baffle itself! http://www.rjbaudio.com/Audiofiles/IEC%20baffle.jpg

[Bear]

Oh, it is the IEC 268-5 test baffle itself! http://www.rjbaudio.com/Audiofiles/IEC%20baffle.jpg

If it were the baffle, then wouldn't similarly-sized drivers from other manufacturers exhibit similar behavior? The RSS265HF (subwoofer) exhibits the same behavior, but a) it doesn't start until 100Hz higher (~500Hz), and b) the effect is much less pronounced. Conversely, I've never seen a Scan-Speak driver's FR plot show anything remotely as bad. Implementation of a testing methodology seems more credible than the methodology itself. This is a pretty severe "wiggle" (combing).

A quick check of a few FR graphs shows that there isn't a similar issue among other drivers tested under similar conditions:

https://www.madisoundspeakerstore.com/approx-10-subwoofers/seas-l26roy-10-subwoofer-d1001-04-4-ohm/

https://www.madisoundspeakerstore.com/approx-10-woofers/scanspeak-discovery-26w/8534g-10-aluminum-cone-woofer-8-ohm/

https://www.madisoundspeakerstore.com/approx-10-woofers/satori-wo24p-8-9.5-egyptian-papyrus-cone-woofer-8-ohm/

https://www.madisoundspeakerstore.com/loudspeaker-raw-drivers/morel-ticw1058ft-titanium-series-10-subwoofer-8-ohms/

https://www.madisoundspeakerstore.com/approx-10-woofers/seas-excel-w26fx-001-e0026-10-aluminum-alloy-cone-woofer/

I'm usually missing something obvious, so pointers/help is appreciated.

[Juhazi]

I wondered the same. But perhaps some manufacturers use a correction file to eliminate (normalize) baffle interferences in IEC measurements?
10" driver's baffle is wider, wiggles happen at lower Hz.

[5th element]

The wiggles don't happen at all for the 8" versions this is clearly a measurement problem.

In fact the 8 ohm RS 270 measures like you would expect it to. I'd use that as a guideline for how the 4 ohm would really perform.

http://www.daytonaudio.com/specs/specsheet.php?prod=295-357

[Bear]

The wiggles don't happen at all for the 8" versions this is clearly a measurement problem.

In fact the 8 ohm RS 270 measures like you would expect it to. I'd use that as a guideline for how the 4 ohm would really perform.

http://www.daytonaudio.com/specs/spe...p?prod=295-357

That's my hope. Or even using the '225 as an analog. However, the '270-4 is such a different beast than the '270-8 (e.g., Fs 20.9 vs 29.6, Qts 0.27 vs 0.47, etc.). The cone and phase plug are no doubt the same, but everything else looked like it might be open to question given its relative newness.

[5th element]

Wow the moving mass of the 4 ohm version is almost twice that of the 8 ohm! Still their upper frequency responses are remarkably similar. If anything the added mass of the 4 ohm version should add stiffness and make them even smoother down low.

In fact I do find it odd that the upper frequency response of the two drivers are so similar. I'd have figured that the added mass of the 4 ohm would alter the breakup in some way. This is assuming that the cone is different. It is possible that all of the added mass is within the voice coil former and the voice coil windings.

[Bear]

Wow the moving mass of the 4 ohm version is almost twice that of the 8 ohm! Still their upper frequency responses are remarkably similar. If anything the added mass of the 4 ohm version should add stiffness and make them even smoother down low.

In fact I do find it odd that the upper frequency response of the two drivers are so similar. I'd have figured that the added mass of the 4 ohm would alter the breakup in some way. This is assuming that the cone is different. It is possible that all of the added mass is within the voice coil former and the voice coil windings.

My guess was that they used a lower gauge (thicker) wire for the voice coil, but that's from a pure neophyte perspective. From a marketing standpoint, I'd expect them to tout a new cone if one was used. Plus, the paper version shows a similar effect, which led me to rule out the cone and suspension.

[tktran]

8” Ellipticor

http://www.scan-speak.dk/?page_id=121&single_prod_id=248

[Bear]

8” Ellipticor

http://www.scan-speak.dk/?page_id=12...le_prod_id=248

With 112dB at Xmax, that may be the lowest distortion professional audio 8" midrange on the market! :-) For home use, I, uh, don't get it. Third driver of a 4-way?

[5th element]

Well this is interesting...

http://www.sbacoustics.com/index.php/coming-soon/sb14st-c000-4/

Given it's tiny size the specs are rather promising. An fs of 1300Hz, decent sensitivity (even if it is 4ohms), Qts bump isn't as pronounced as other small neo tweeters and it's ruler flat too. The best bit is that it should fit inside the voice coil of pretty much any standard driver with a 25mm voice coil. So for those of us that like building our own coaxials...it could be perfect.

This looks like it's the tweeter that SB have used within their PFC coaxials...it should be dirt cheap.

[Zvu]

.......... for those of us that like building our own coaxials...it could be perfect...

Matt, why would you build your own coax ?

I mean, you're in UK and there are lots of new and used KEF's for reasonably low price. I consider KEF and TAD coaxes second to none (thanks to Andrew J.) and i can't see the reason for trouble that one has to go through to cut and modify the loudspeakers when there are readily available options 5, 6 and 8 inch that work better. I've seen Q100 and Q300 goes for 150-200 pounds a pair. If you really want to step it up a notch with better motors, go with R series - but new Q150 and Q350 have ribbed cones and motors from R series as i understand. Tweeter in Q100 has breakup at 40KHz. If you'd want to buy that kind of tweeter from Seas, Scan-Speak, TL or SBacoustics, you'd have to spend a lot of money. They made cones and suspensions to suit the tweeter, power handling is enormous when relieved od bass duty. People want to buy raw KEF drivers on a number of forums that i read but no one seems to realize that they really should buy used or new speakers and you get the trimming for it (since KEF puts its drivers into the cabinets they don't try to make them pretty). Tangerine waveguide obviously does the job and lots of knowledgeable guys worked on that for years. Why wouldn't we use it if we can ? I compared prices of finished KEF's with prices of coaxial drivers available to DIY'ers and i haven't found anything remotely similar in performance, but every one of those coaxes was more expensive than finished Kef loudspeaker with driver of that size.

[5th element]

I do look on ebay, every now and again, for KEF units, but never really find anything that interests me. I've never been a fan of the KEF drivers anyway, everything about their drivers is excellent except for their HD performance. I'll admit, I'm a HD snob and most of KEFs drivers are poor in this area, at least in my opinion, and in relation to the HD performance you get vs the price you pay.

I'm also extremely specific about the things I look for in drivers, some tick my boxes and some don't.

[Zvu]

I wasn't a fan untill they ditched the plastic cones. Few days ago i got my R300 from UK. It will be interesting to see how they behave regarding distortion. There are distortion measurements on SoundStagenetwork done at 90dB from 2m distance. THD in R500 looks quite good. It'll be interesting to see how does 2-5 harmonics look like with REW.

[5th element]

http://www.audioexcite.com/?page_id=3614

It's okay but nothing special.

[Zvu]

Well, i guess i'm not that much of a HD snob - this looks very good to me. Diffraction and resonances seems much more sinister than difference in distortion performance that is about 0.3% higher than say Seas Excell. On the other side, lack of mid cone breakup, mild off axis response of midrange, tweeter breakup at 40KHz and measuring that good 60 deg. off axis - now that's not something i can make on my own with regular suspension and regular cone midrange/midwoofer and of the shelf tweeter. It ticks all of my boxes - since i don't see distortion of 0.3-0.5% as a problem.

P.S. - Though i do understand personal priorities and i see where you're coming from.

[5th element]

It ticks all of my boxes - since i don't see distortion of 0.3-0.5% as a problem.

P.S. - Though i do understand personal priorities and i see where you're coming from.

From my point of view it's the fact that it rises the way it does when the drive level is increased. Obviously you expect it to rise, but in general terms a HD3 level of 0.3-0.5% is mediocre in terms of what other drivers can routinely do.

If you look at Goran's Excellent design...

http://www.audioexcite.com/?page_id=5200

You'll see what I mean vs how the third order changes with drive level, it barely moves and is at a lower level. I like my third order harmonics to remain at ~0.1% or lower if possible. And it is usually possible. Although I have been known to use drivers that don't perform this well from time to time

[Oneminde]

I am struggling with tweeters. (Prices as for me in Sweden)

The new Bliesma T34A-A alu tweeter is a serious contender and it is fast grabbing attention, me included. Out of the gang I am looking at, its the most expensive at $427 - SPL vs Freq done by Troels Gravesen



A level down in price and we have the Accuton C30-6-358 which cost $382 and perform very well. Tony Gee from Humble homemade Audio had this to say; "The Euridice play fantastic! They just sound very realistic and true to nature, the Accuton's are phenomenaly precise but it never
gets tyring. It is definitely a very successful design, chapeau :-) " - SPL vs Freq done by Audioxpress



Then there are two SBA Be dome tweeters that was just released and show promise. The SB29BAC-C000-4 and SB29BNC-C000-4. They cost roughly the same $337-340

The SB29BAC-C000-4 seem to be a better choice if one apply the 1.5 octave rule for the xover: Fs: 600 Hz, mean its safe to xover at 900 Hz and this driver have no issue doing so.



The SB29BNC-C000-4 has an Fs of 950 Hz and applying the 1.5 octave rule as minimum Fs distance to xover we get 1425 Hz.



The price difference between SBA Be tweeters and Bliesma is for many a seriously good tweeter, so the performance vs cost is a totally different ballpark. And in the end, we are talking about premium aluminum vs premium ceramic vs really good beryllium. Tough choice.

Any advice ?????

[Bear]

Any advice ?????

SB still show the SB29BNC as "coming soon", and it's not on Madisound's website yet. However, I did find a backorder for it at Solen:

https://solen.ca/products/speakers/home-speakers/tweeters/sb29bnc-c000-4/

That's ... a great price, and it settles the question that 5th Element/Matt and I were having a few posts ago.

The ~$50 price point used to be a sweet spot in the market, but inflation seems to have moved that point up to the $80 - $100 range, leaving the $50 price point a bit less crowded. If it had more competition, I would say that the SB29RDCN is merely a good tweeter among a bunch of other good tweeters. Given the market, though, I'd say that SB29RDCN (non-Be) is a great tweeter at the ~$50 - $60 price point. Why?

1) Small size - with a 72mm diameter faceplate, it allows for much closer CTC distances vs 100mm+ tweeters. Some of the larger-format tweeters have to accommodate a lower XO point because you just can't get the spacing right to a 18cm midwoofer or an MTM arrangement.

2) Piston size - The 9.6cm^2 radiating area (Sd) with a 0.25mm stroke means that you can hit 100dB at around 1750Hz (Xmax limitation).

3) Low-ish Fs - Second place in Zaph's contest from a long time ago had the tweeter crossed at 1.1kHz LR6. More importantly, a crossover point in the 1600 - 2000 range only requires an Lpad, and not an impedance flattening shunt. That reduces the implementation cost if you are building a passive crossover.

The net effect of the three advantages for the normal SB29 -- it is really, really easy to use in the 1600+ Hz range. It will fall pretty naturally into a B3 slope with second order electrical, which pairs nicely with LR4 on a woofer to align phases/acoustic centers.

Neutral characteristics:
1) Distortion - This is a pretty clean tweeter (-50dB F3) through basically all of the range through which you would likely use it. F2 is a little high. But there are other tweeters (SB26ADC) which are even better at a similar price point.

"bad" characteristics:
1) Frequency response 1 - there's a "hump" in the FR through much of the likely XO points (+3dB at ~1900Hz). Deal with it or live with it. Dealing with it is about the only place where the part count for the XO is likely to get elevated.
2) Frequency response 2 - It's got a rising response from 8kHz on. As above, you can live with it or deal with it. Playing with the Lpad values can tame most of it. A small (~0.05mH) inductor in series with the tweeter will kill it (but will also affect phasing).

For the Be version, I'd expect even better distortion, but the rise in Fs may push the desired crossover point up to 3KHz for an "easy" version. The magnitude of the impedance spike at resonance is pretty small, so one may get away with a <2kHz XO point without having to use a heavy hand for impedance compensation (80uF+ caps can get expensive!). The FR for the Be version exhibits none of the frequency response issues of the soft dome version, so it shouldn't require a lot of parts for shaping (slight downward tilt from 2kHz - 14Khz). In other words, it probably has a lot to recommend it and should be an "easy" driver to work with, but within an indeterminate performance envelope.

But there are also several really good tweeters at a similar price point (e.g., Scan-Speak Air Circ and derivatives). Whether it is better for your application than readily-available alternatives is a question you would need to answer.

[Oneminde]

Thank you for your advice.

But soft domes are out of the question. I am never fully satisfied with soft domes. At the moment, Accuton C25-6-158 and SBA29BAC are sailing up to the top. Accuton has a low distortions, for the SBA this is an open question since no tests has been done. Since the price is roughly the same for both, the choice is therefor much tougher.

[Bear]

Thank you for your advice.

But soft domes are out of the question. I am never fully satisfied with soft domes. At the moment, Accuton C25-6-158 and SBA29BAC are sailing up to the top. Accuton has a low distortions, for the SBA this is an open question since no tests has been done. Since the price is roughly the same for both, the choice is therefor much tougher.

Since these are new diaphragms on existing motors, the existing models are your best look at how they will perform. I do not know what your requirements are, but the -6640 Scan Speak is also (loosely) within this expansive price bracket, and its performance is well documented. If you are only considering metal dome tweeters, and budget is a concern, then this is a strong benchmark for value:

http://hificompass.com/en/speakers/measurements/sbacoustics/sb-acoustics-sb26adc-c000-4

If you want something new, then some amount of application risk is inevitable.

[Oneminde]

The SB26adac is not bad at all, and they are releasing a new version of that tweeter which move the first breakup up by adding a layer of ceramic (AlO2). Its apparent on the on-axis at 25kHz. The only non affect part of the off-axis at 60 degree, but other than that, the SB26CDC is a better version. $15-20 more money than the SB26ADAC

SPL vs Freq for the SB26ADAC



SPL vs Freq for the SB26CDC

[wolf_teeth]

My math is not in agreement on your 1.5 octave ruling. If the Fs is 600Hz, then 1.5 octaves above that is 1.8kHz. 600 to 1200 is one octave, and half of 1200 to 2400 is 600 Hz more. For 950Hz, double is 1.9k, and again to 3.8k for 2 octaves. 1900 + 950 = 2.85kHz for the 1.5 octave rule.

Later,
Wolf

[Oneminde]

Sorry about the math, it was an honest mistake, my brain farted.

1.5 octave rules for the two tweeters is then; @ Fs = 600 Hz, 1.5 octave above is: 1800 Hz. And @ Fs = 950 Hz, 1.5 octave above is: 2850 Hz

[Bear]

My math is not in agreement on your 1.5 octave ruling. If the Fs is 600Hz, then 1.5 octaves above that is 1.8kHz. 600 to 1200 is one octave, and half of 1200 to 2400 is 600 Hz more. For 950Hz, double is 1.9k, and again to 3.8k for 2 octaves. 1900 + 950 = 2.85kHz for the 1.5 octave rule.

Later,
Wolf

IIRC, half an octave is the base frequency multiplied by sqrt(2), but 0.5 works for most calculations. In this case, I'd recommend looking at the HD performance, the target SPL (for pistonic output), and the shape of the impedance spike to determine whether a driver is worth a deeper look.

For example, the Scan-Speak Air Circ has a Fs of 470Hz but a Z0 of 18.4 ohms. It can cross low, but needs a fair bit of impedance compensation to do so reliably if using a passive filter. One of the nice things about these SB units is the relatively low impedance at resonance.

[wolf_teeth]

Sure, no disagreement there. I was only commenting on his ROT. Of course HD should be looked at, and it isn't cut and dried to just use the ROT described here. True that Zmax at resonance can cause the dreaded nasal-buzz without being compensated if magnitude is high enough, but just because it's minimal in magnitude also doesn't mean that it won't increase in HD when going lower.

I recently used the TW022WA06 in a 2-way, as an example. Zmax is about 9 ohms at 750Hz, which is well damped. However, 2nd order HD crossed the -40dB threshold at 2.5kHz, so I xover'd above there. I know this is a 22mm tweeter, but in this case, lower it should not go.

Later,
Wolf

[Bear]

Sure, no disagreement there. I was only commenting on his ROT. Of course HD should be looked at, and it isn't cut and dried to just use the ROT described here. True that Zmax at resonance can cause the dreaded nasal-buzz without being compensated if magnitude is high enough, but just because it's minimal in magnitude also doesn't mean that it won't increase in HD when going lower.

I recently used the TW022WA06 in a 2-way, as an example. Zmax is about 9 ohms at 750Hz, which is well damped. However, 2nd order HD crossed the -40dB threshold at 2.5kHz, so I xover'd above there. I know this is a 22mm tweeter, but in this case, lower it should not go.

Later,
Wolf

Yeah, the problems with rules of thumb is that there is (usually) another thumb and a few other fingers, to boot. I think Oneminde's search for a tweeter probably deserves a separate thread where a more in-depth discussion might be had about specific requirements, which are currently unstated beyond "metal".

Oh, yeah, we should probably throw in a nod to "slope" on that decision tree, as well. LR2, LR4 and LR8 are going to have some very different requirements and behaviors.

[Bear]

Madisound is now showing the SB29BNC on its site. The answer to the price question was, in fact, under $300, but not by much...

https://www.madisoundspeakerstore.com/beryllium-dome-tweeters/sb-acoustics-sb29bnc-c000-4-29mm-beryllium-dome-tweeter-w/grille/

[Zvu]

I think that thread title should be renamed to -Interesting drivers- since it is of no importance where are they from if performance is there.

Here's pdf with measurements of new Epique midwoofer and two RST tweeters from Dayton.

https://www.dropbox.com/s/sfie9k8cbmfvqkh/voice-coil-september-2018-16-26.pdf?dl=0

[Audiophile100%]

...but the RNX2 part looks interesting...

hi jon, i hope you are fine
i'm very instrested to understand the mai differences between nrx and nrx2 and first the main application in with they must be integrated.

[kevinlin1013]

Tony Gee released his Duelund Coherent Audio Monitor.

http://www.humblehomemadehifi.com/download/Duelund-Coherent-Audio-Monitor.pdf

[wolf_teeth]

I know it's +/-2dB, but the spectral tilt will leave a quite murky-sounding midrange, as well as a bit of excess sparkle in one spot, IMO.

Also- WHY did the manufacturer have to place that yucky logo on the tweeter so you HAVE to mount it cardinal-style? IMO, cardinal mountings of drivers do not look the best, and I would prefer it be mounted 45 degrees rotated. I understand some tweeters like ribbons, AMTs, or some multi-hole drivers make this more difficult, and then you might not have a choice; but when there is a choice- I'd prefer no logo and the option to do so.

Later,
Wolf

[ergo]

It has a nice looking clean and simple xover.... but seems indeed it has a bit of the "BBC dip" type of tuning in 2..3kHz. I'd really love to see a full polar plot and power response. I've never really seen a design where 8'' woofer mated with a tweeter without any waveguide would produce a good even power response. So that in addition to small dip on axis might together make it even more laid back in that range. But as always it's hard to judge sound from data on screen alone.

[wolf_teeth]

I don't totally disagree with the sentiment that measurements don't tell the whole story, but I know how mine measure when I'm finally happy with them and that ain't it.
Later,
Wolf

[Bear]

I'm sure that I'm late to the party knowing this, but I was pleasantly surprised to see that Parts Express is now carrying Wavecor products.

https://www.parts-express.com/Search.aspx?keyword=wavecor&sitesearch=true

Don't look for the SW223xxxx products, because those aren't there (maybe later?). I am somewhat tempted to grab a WF120BDxx for a project, though.

[technodanvan]

Yeah, I'm really hoping those show up there sometime, possibly with their smaller SW182xxxx brethren. It'd be great to have a 'local' source for Wavecor products, and maybe save a few bucks in the process.

[fish fingers]

5" carbon SB due out soon.

[5th element]

5" carbon SB due out soon.

I wish they'd do a metal Satori already.

[Bear]

I think that thread title should be renamed to -Interesting drivers- since it is of no importance where are they from if performance is there.

I'd agree, but a moderator has to change it.

[5th element]

I'd agree, but a moderator has to change it.

Done

[Zvu]

I'd agree, but a moderator has to change it.

Done

Yey

[igy137]

I wish they'd do a metal Satori already.

yup, an alu dedicated midrange with satori motor

[Bear]

yup, an alu dedicated midrange with satori motor

It makes one wonder whether Revel (really: Harmann) have that tied up in an exclusivity agreement.

[5th element]

It makes one wonder whether Revel (really: Harmann) have that tied up in an exclusivity agreement.

Maybe, from all the screen-shots I've seen Revel's, SB made, drivers are built on SBs standard range motor. Not that there's anything wrong with that!

[Bear]

Maybe, from all the screen-shots I've seen Revel's, SB made, drivers are built on SBs standard range motor. Not that there's anything wrong with that!

The main advantage that I would expect from a Satori motor would be a reduction in rear-wave masking. A shift to neo magnets would drop the Le, but the 15cm and 17cm units are already pretty good there. Perhaps they could increase the magnetic flux to get more sensitivity and/or power handling?

Looking at the specs on the 12cm ceramic drivers, though, this is where the Satori treatment looks like it would do the most good. I'd love to use it for my center channel project, but the Le and magnet size have me focusing on the 15cm version instead.

[Jonasz]

http://www.sbacoustics.com/index.php/coming-soon/7-satori-coaxial/

Satori coax