i do believe that for satori type of drivers, the mfr would have included a cone edge coating if they thought it would increase the performance, or change the surround to a high damping surround
no, to me it looks like sb acoustics have set for a goal to minimize driver losses or something and a non linear freq response is just the backside of that coin
no, to me it looks like sb acoustics have set for a goal to minimize driver losses or something and a non linear freq response is just the backside of that coin
The one set of Festrex i played with were very disappointing, but there products are a moving target an dthe original designer left some time ago i believe.
Very much a niche market.
dave
Except for maybe bass drivers, preferred by me, no bump up to scrw up what is coming off the edge of the cone.
dave
As I say, you can believe me or not (obviously not 😉 ), but manufacturers actually do have cost considerations for mass-production drive units, and if you think these are any different, I'm afraid they aren't.
Keep in mind that the surround isn't the issue: the cone edge resonance is the cause. Easily shown by the total absence of said over the same frequency range in the majority of metal cone units optimised for piston behaviour. Now, they can fit a surround with greater damping to stop the cone edge flopping about, but to do so without changing the spec. significantly will require a more expensive piece of engineering, such as applying an asymmetric type, which requires more development time, and costs more to produce consistently if you aren't cranking out units in 5 figure batch numbers. The alternative approach of edge-damping requires a complete new production stage, with another set of tooling and an addition to the final stage of the line, since it has to be applied to complete drivers. This is costly, increases potential failure rates due to variation and simple accidents with complete units, takes time and requires skilled staff to produce consistently.
Against these, for drive units retailing at £122 (MW-16P)? Yes, they do what they can to keep the margins in check. Edge-damping? Another £35 - £40 on the retail price. I like the MW-16P incidentally. One of my go-to current production 6in paper cone midbass units. But they aren't made without consideration of cost.
That they are. I've heard their units on two occasions. Both times walked away thinking, as far as sonic performance goes, nothing special. I've heard [much] worse, but for that sort of money? Not for me. I don't think the out & out performance is the sole goal here -it's the artistry involved in the production & whether you buy into it. Same for the Maxonic's. My friend Dave had a set of their field coils driven by a full Kondo setup at last year's North West Audio Show. The room didn't do them any favours, but the performance wasn't £75,000 worth to my ears (don't ask about the cost of the amplifiers or turntable). Obviously, I still wanted every piece of kit in there -more beautifully machined billets of metal, glowing dials, gauges and valves than you could shake a fretful porpentine at. Even if it didn't necessarily sound as good as it looked, or the near half-million pound price tag.
The issue is the transition to a different material at the junction of the cone/surround. There will always be at least some reflection.
dave
dave
Agreed, that's the transverse reflection, or a significant part thereof. But there's also the resonance of the cone periphery when it's insufficiently rigid, which is the main cause of most of these 800Hz - 1.4KHz modes (absent in most equivalent metal cone models of the same dimensions, notwithstanding alloy wideband drivers that are conceptually closer to soft cone midbass units in that sense).
In a FR those modes also indicate the transition to (hopefully controlled) to resonant behaviour required to reach as high as they do.
dave
dave
I think this is a big time improvement. This impacts the sensitive-to-the-ear 'presence' range of 1,000 to 3,000 Hz. Troels didn't mention that the 2nd harmonic distortion peak of 10 to 15 dB in the 1,500 Hz range commonly found on paper and polypropylene cones, at the surround resonance, should also be greatly diminished, or raised in frequency. Results should show on the impedance curves too, reducing the blip at the same frequencies. This should clean up this range, allowing more seamless crossovers to the tweeter. People made a big deal of the SB Acoustic NAC and NBAC woofer aluminum woofers with the radial ribs that cleaned up this area. Now some are waiting for the SB Textreme woofers with hopefully some similar characteristics, at great expense.
You typically have loudspeaker resonances with paper & poly cones:
Spider suspension : ~ 250 Hz
Cone bell mouth : 800 - 950
Surround reflection: 1,000 - 2,000 Hz
You typically have loudspeaker resonances with paper & poly cones:
Spider suspension : ~ 250 Hz
Cone bell mouth : 800 - 950
Surround reflection: 1,000 - 2,000 Hz
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SB Acoustics did add a narrow coating strip on their MR16-8 midranges. In the Troels article mentioned in this thread, go to the heading "SBAcoustics MR16P-8and -4 midrange driver" about 2/3rd's down the article. The one with two pictures side by side. Look closely at the one showing the back of the MR16-8 midrange. On the back of the cone, about 1/4" from the edge you will see a shiny bead of elastomer.
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I have seen that kind of thing before on other drivers, what i do on the Fostex is similar but on the backside (where the surround attaches — the ones above attach at the front).
dave
dave
Hi Dave,
sure that´s a very small niche... but the original Feastrex designer Teramoto-san seems to be active again with a new product:
AFT model 7
and of course it comes at a price.
But then, if you look into the market of high-priced fullrange drivers, there´s quite a choice to make, there´s also Cube, Voxativ, Songer Audio, Fertin Acoustics, WvL and some of them at even higher prices.
Of course buying such a driver requires some crazyness (I know that well, ´cause I´ve done it), is never economic (you´re deep deep in the diminishing returns) and can´t be argued rationally.
All the best
Mattes
I used felt pads to tame cone edge resonances of SEAS MR18 coaxial. It has inverted roll surround which is ok for a midrange.
SEAS MR18 3-way
Shared album - Juha Sirkka - Google Photos
https://photos.app.goo.gl/FAQSdz2T48k2X6QFA
SEAS MR18 3-way
Shared album - Juha Sirkka - Google Photos
https://photos.app.goo.gl/FAQSdz2T48k2X6QFA
i hear what you say and i do understand that more or less ALL products have some cost constraints. but i do not think this is the case here, i do believe it has more to do that you just can not maximize all parameters, if you boost some then others will go down, so it is all a balancing act, and this is the reson for no cone edge treatment and not the cost
like, i do not think sb acoustics chooses such soft and thin surrounds because they are cheaper then thick and hard surrounds
'Thick and hard' surrounds are neither more or less expensive than, nor an alternative to, 'soft and thin' surrounds. Dimensions, thickness, compliance etc. are not mutually exclusive factors, and there are a variety of ways of achieving a desired set of results. For the sake of interest, thin surround materials are often more, not less, expensive than thicker types due to the difficulties in consistent production and the higher QC failure ratios. This is particularly the case with high compliance designs. For example, when Markaudio developed the EL70 for CSS about 10 years ago, they had to scrap several batches of surrounds and spiders for precisely this reason.
Be that as it may, the point is not that SB has significantly cut costs on surround material per se. They've used what they needed in order to achieve a given set of general mechanical characteristics. However, in doing so, they have accepted a compromise in terms of controlling the cone edge-resonance. Which is what is being referred to here. They could in principle address that without significantly impacting the desired qualities, but to do so would result in a higher unit cost. Edge damping is one method of achieving this (as Troels has demonstrated), asymmetric surround profiles are another potential means, but neither come cheaply for various reasons, some of which are referred to above.
Be that as it may, the point is not that SB has significantly cut costs on surround material per se. They've used what they needed in order to achieve a given set of general mechanical characteristics. However, in doing so, they have accepted a compromise in terms of controlling the cone edge-resonance. Which is what is being referred to here. They could in principle address that without significantly impacting the desired qualities, but to do so would result in a higher unit cost. Edge damping is one method of achieving this (as Troels has demonstrated), asymmetric surround profiles are another potential means, but neither come cheaply for various reasons, some of which are referred to above.
But given how good WAWs like yours with A10.3 and mine with A7.3eN i don’t see a need. Even without having to work within a budget i’d prefer spending money on other kit and music.
The Frugal-Phile™ in me.
Good value (at least from client feedback, i’ve not heard them) threw out the value equation when prices more than tripled when they went to distribution.
The Voxative are scary prices, and i’ll have to look up some of the others. Thanx for mentioning them.
How many of these sell just because they are so pricey i wonder.
dave
Good one, i have seen them on some whizzers, the nice Sansui F10 one for instance (if i recall correctly).
dave
More like 15 years ago i think now,
The EL70 was really the 1st MA driver to have an impact on the NA market and was outstanding for the price. Amazing bass potential, still number 2 (behind the A10.2) in the historical lineup.
dave