Like Nemophyle allready said, the 102kep or the 135kep from monacor are true gems among the midrange (kevlar) units.
It's like a coincidence but today I just disassembled an old projekt of mine with a 102kep. Since I didn't have any measure equipment back then I was curious about how good this unit actually is. I measured it today and the frequency responce and decay diagram are impeccable! I think I'm going to use it in some highend projekt in the near future together with the Seas Noferro12 tweeter wich is to me his ideal partner.
It's like a coincidence but today I just disassembled an old projekt of mine with a 102kep. Since I didn't have any measure equipment back then I was curious about how good this unit actually is. I measured it today and the frequency responce and decay diagram are impeccable! I think I'm going to use it in some highend projekt in the near future together with the Seas Noferro12 tweeter wich is to me his ideal partner.
There is no best cone, but there are goof cones for a specific work and price/value ratio. If you would like to proceed to a high sensitivity design, here is another candidate, if you are willing to pay a little more:
http://www.phlaudio.com/datasheets/17_pdf/1220_1230.pdf
Really crispy clean even in very high listening levels, able to reveal information that is lost in many insensitive drivers, exceptionally dynamic, relatively smooth response.
You would have to perform your measurements though, since the manufacturer doesn't provide any;-)
Regards,
Thalis
http://www.phlaudio.com/datasheets/17_pdf/1220_1230.pdf
Really crispy clean even in very high listening levels, able to reveal information that is lost in many insensitive drivers, exceptionally dynamic, relatively smooth response.
You would have to perform your measurements though, since the manufacturer doesn't provide any;-)
Regards,
Thalis
Thiel used the 13M8640 long ago, in their first three way; the speaker that made their reputation. I used the 8636 coated Kevlar to good effect in a commercial design that was on the market for ~ 5 years. By modern standards, both would be sweet and a bit veiled, the 8640 more so. But both are very musical drivers.
beppe61 said:
I’m not a huge advocate of this concept. Either way, most of the claims I have seen regarding staging depth involved preference towards very directional speakers such as electrostatics and other dipoles in which delayed reflection from the rear wall also contributes to the sound.
Whether you are going for this ideal or not, some level of controlled directivity is actually a “good idea” as Owdi said before.
beppe61 said:
Driver directivity does increase with frequency.
No not at 80Hz!!!
I think it is most likely that you have heard this number referring to the frequency at which our ears can start to hear the direction from which bass is coming!? Don’t confuse that with the directivity of drivers!For any given driver the point at which directivity starts is a frequency called “Fd” and is dependant on effective driver diaphram diameter
(Effective diameter can be roughly estimated by measuring the distance between the centre of the suspension on one side to the centre of the suspension on the other side)
Fd = 109500 / diaphram diameter in mm
Dome shaped drivers sometimes may have slightly better dispersion because the initial wavefront they create is a little more sperical.
Fd is around 1.3kHz for the 4 inch drivers I mentioned
Fd is around 860Hz for the Vifa XG18 I agree with Owdi & Zaph that tis is a great driver
Fd is around 3.9kHz for your average 1” tweeter!
Drivers become gradually (not suddenly) more directive above Fd which is why we happily use 1 inch tweeters.
For mid range drivers most sane people are happy to use a driver well above Fd. I don’t actually think about Fd when designing but as an observation my mids are most often used to within 2.4x - 3x their Fd.
beppe61 said:
If your mid driver is – 4.00dB at 60deg off axis at the crossover point then the net total is likely to be more like –1.77dB at 60deg off axis at this point.
Smaller than you might imagine?
beppe61 said:
With 6dB cross overs any dip will be much wider. I would recommend 12dB/oct crossovers in most cases for a large number of other reasons. Between the mid and woofer a 6dB might be better.. depending on the final low frequency response and capability of the mid.
Zaph said:
Listen to Zaph.. He knows what he is talking about!
I would not use kevlar for the mids, use a good paper, poly, glassfiber cone instead. Less breakups and easier to filter. If you want pistonic operation consider Alu/ Magnesium cone, but these cone's need more work on the x-over.
So in short, look at Seas L15, W15, Scanspeak 15W, C-quenze 15H, Peerless HDS/ Exclusive, Vifa PL 14 and so on.
You can also consider a larger cone to reduce distortion, Vifa XT & XG 18 are great value. Or Dayton RS180/ Seas L18 for alu cone. Or my personal best 18H.
So in short, look at Seas L15, W15, Scanspeak 15W, C-quenze 15H, Peerless HDS/ Exclusive, Vifa PL 14 and so on.
You can also consider a larger cone to reduce distortion, Vifa XT & XG 18 are great value. Or Dayton RS180/ Seas L18 for alu cone. Or my personal best 18H.
I generally agree with the Kevlar comments above; in the case of the 8636 a dampening "goop" tames the typical fierce Kevlar high end breakup.
The only Aerogel I ever evaluated, some 5 or 6 years ago also had a bad high end breakup. As a rule of thumb, based on limited experience, polypropylene is a more reliable choice than other cone materials.
Since this is a first project, I do strongly urge using drivers with a flat frequency response, without a strong peak at the high end.
The only Aerogel I ever evaluated, some 5 or 6 years ago also had a bad high end breakup. As a rule of thumb, based on limited experience, polypropylene is a more reliable choice than other cone materials.
Since this is a first project, I do strongly urge using drivers with a flat frequency response, without a strong peak at the high end.
taco wrote:
I surely don't agree with that. I have experience with several kevlar units from monacor and even the 200ke (8" unit) is very easy to filter.
What I don't understand is why you say that glassfiber cones are easier to filter and have less breackup. All the glassfiber cones I know of have a very large resonance peak somewhere in their freq. response.
I surely don't agree with that. I have experience with several kevlar units from monacor and even the 200ke (8" unit) is very easy to filter.
What I don't understand is why you say that glassfiber cones are easier to filter and have less breackup. All the glassfiber cones I know of have a very large resonance peak somewhere in their freq. response.
Curmudgeon said:Dear Sir,
please excuse my belated reply but I am having some problem with my job.
First of all I cannot thank you enough for the amount of valuable information you are giving me.
It will take me the next three months to study all of them !
> ... Imaging is governed by several factors.
Driver and to some lesser degree crossover component matching, room/furniture reflections, placement, and source of course.
I already know that environmental reflections are nasty for imaging (I should really do something my listening room).
I would want anyway that the speaker is not a limiting factor.
> I don't listen much for imaging, as I do not hear pinpoint imaging at live performances.
Maybe it depends on which kind of music are you referring to.
If you listened to a small ensemble in an acoustically reated room you should perceive the relative positions of the instruments (and players of course).
If you are referring to a Guns and Roses album, well ...
And of course the "image" must be in the recording.
> I don't design for it as such, but find that speakers that do all other things well will image well as well.
Well this is indeed a point.
I can see that at the end a series of measuremts is always used to evaluate the final quality of a speaker.
I read somewhere for instance that a speaker with a good frequency response (i.e. flat) has a lot of possibilities to image also well.
This flatness should be maintened at different dB level.
And I am afraid that this is not so common.
I mean, a speaker quite flat at a average level of 90 dB is also flat at 80 dB ? It should be interesting to check.
> And super dispersion is not your friend in the normal home listening environment.
More reflections from the side from walls, furniture, floor, etc. will give more strength to the delayed signals.
The combination of direct and delayed at your listening point will be more raggedness in frequency response, and of course time "smearing", as one meter is 3 ms of delay.
How true are you. I read recently about a listening session of a system placed out-door. It imaged greatly.
But the outside noise of course was a problem.
> Columnar speaker designs restrict dispersion, and can image very well.
Actually I like slim tower speaker quite a lot.
That could be a nice solution indeed.
[/B]
Thank you veyr much again for your very valuable advice.
Kind regards,
beppe
filgor said:I’m not a huge advocate of this concept.
Either way, most of the claims I have seen regarding staging depth involved preference towards very directional speakers such as electrostatics and other dipoles in which delayed reflection from the rear wall also contributes to the sound.
Thanks a lot Sir for teh very kind and helpful advice.
Stated that reflections are bad for the sound, I do not like dipoles just for this reason.
The rear emission is to be cancelled in my view of things.
Actually, damping the rear and front walls improves the soundstage reproduction immediately, in my experience.
> Whether you are going for this ideal or not, some level of controlled directivity is actually a “good idea” as Owdi said before.
Driver directivity does increase with frequency.
I see that from the frequency response graphs.
My reasoning is that if I set the crossover to get flat response on axis what happens out of axis ? could I find a dip in the response?
> No not at 80Hz!!!
Yes that is. Is it true? if so only frequencies above 80Hz contribute to the reproduction of soundstage.
This is a fundamental point in my view.
> Don’t confuse that with the directivity of drivers!
For any given driver the point at which directivity starts is a frequency called “Fd” and is dependant on effective driver diaphram diameter.
(Effective diameter can be roughly estimated by measuring the distance between the centre of the suspension on one side to the centre of the suspension on the other side)
Fd = 109500 / diaphram diameter in mm
Dome shaped drivers sometimes may have slightly better dispersion because the initial wavefront they create is a little more sperical.
Fd is around 1.3kHz for the 4 inch drivers I mentioned
Fd is around 860Hz for the Vifa XG18 I agree with Owdi & Zaph that tis is a great driver
Fd is around 3.9kHz for your average 1” tweeter!
Thank you so much for this very interesting info !
I did not know completely.
... If your mid driver is – 4.00dB at 60deg off axis at the crossover point then the net total is likely to be more like –1.77dB at 60deg off axis at this point.
Smaller than you might imagine?
Yes. So the actual effect should not that bad.
> With 6dB cross overs any dip will be much wider.
I would recommend 12dB/oct crossovers in most cases for a large number of other reasons.
Between the mid and woofer a 6dB might be better.. depending on the final low frequency response and capability of the mid.
You have raised another fundamental point: the crossover slope.
I read that with active digital crossovers very steep slopes can be obtained with the result of, between other things, an exceptional soundstage reproduction.
So the steeper the slope the better, it seems.
Listen to Zaph.. He knows what he is talking about!
Thank you so much for the very kind and valuable reply.
Kind regards,
beppe
bombardon73 said:
I think you are talking about some other units than I do, Vifa XG 18
An externally hosted image should be here but it was not working when we last tested it.
and here here a link to Seas Excel Fiberglass
I do not trust the measurements of Monacor (a lot of smoothing)!! If you are on a buget use Dayton RS instead.
Dare to disagree again with me
.The request is for a midrange for a first project, and there is a budget; not overly tight, but still, a budget. For ease of crossover development, the mid should be smooth to AT LEAST 6 kHz, and preferably to 10K.
For a while, there was a trend towards cones that traded speed and transparency for upper mid breakup; Kevlar, metal, Aerogel, and even some paper cones had severe breakup, sometimes just out of the mid band. These required steep crossovers and traps and were just a general pain. Recently smooth rolloffs seem to be back in fashion.
The most transparent mid I've ever encountered is the ATI/Skaaning 4" mid, which has a very domesticated high end rolloff, so it can be done.
My feeling, I guess, is that for a first project having good sound and a good chance of success is more important than trying for great sound with a lot of potential pitfalls.
For a while, there was a trend towards cones that traded speed and transparency for upper mid breakup; Kevlar, metal, Aerogel, and even some paper cones had severe breakup, sometimes just out of the mid band. These required steep crossovers and traps and were just a general pain. Recently smooth rolloffs seem to be back in fashion.
The most transparent mid I've ever encountered is the ATI/Skaaning 4" mid, which has a very domesticated high end rolloff, so it can be done.
My feeling, I guess, is that for a first project having good sound and a good chance of success is more important than trying for great sound with a lot of potential pitfalls.
Taco, that vifa unit looks good. But if I look at the freq response I wouldn't use it above 2Khz (1st peak at 3Khz, 2e at 4,5Khz). Also, you can see some irregularities in the impedance at 400 and 1200hz (myabe you can also see this in the harmonic distortion diagrams if you have those).
Ok, Monacor uses smoothing on their curves (most manufacturers do), But I know from my own measurements and those from Klang&Ton that those kevlar units are REALLY good. Better then those from Davis and Focal e.g..
Also, I know the Dayton RS series. I have a two way system with the RS150. A very good unit, the 1st real resonance peak is at 9Khz. I cross it at 2,5 Khz with a 12db filter wth no problems. I don't need any LCR networks to dampen it's resonance peak.
Ehm, one thing, the Jordan jx92 would be a very good contender as a midrange unit.
But if I would have the money I would buy one of the Thiel&Partner keramic units.
Ok, Monacor uses smoothing on their curves (most manufacturers do), But I know from my own measurements and those from Klang&Ton that those kevlar units are REALLY good. Better then those from Davis and Focal e.g..
Also, I know the Dayton RS series. I have a two way system with the RS150. A very good unit, the 1st real resonance peak is at 9Khz. I cross it at 2,5 Khz with a 12db filter wth no problems. I don't need any LCR networks to dampen it's resonance peak.
Ehm, one thing, the Jordan jx92 would be a very good contender as a midrange unit.
But if I would have the money I would buy one of the Thiel&Partner keramic units.
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