High Sensitivity drivers...Where?

Hi there folks,

My first post in an actual 'topic' - be gentle with me!
I wrote something about me in the introduction, and interested are directed to that thread! ;)

Well, to the question:
If I want to build a loudspeaker with a system sensitivity of, lets say, 95dB and keep a fairly high impedance, lets sa >5ohm... Where do I fins driver units for this? Scan Speak, Vifa, Seas and so on does not have anything apealing...

I am hoping for a nice two way solution, preferably D'appolito. The Tweeter is not an issue when it comes to high sensitivity.

The box size and price....well...lets ignore those two aspects for a while...and just discuss the driver units!

And I am not interested in horn loaded constructions...

Awaiting answers and ideas!
Look, your project is challenging: hifi systems with REAL 95 db efficiency are not so many, and all belonging to a very specific segment: we can list the Klipsch horns (Klipschorn, La Scala etc.), some BIG Tannoy (GRF memory etc.), plus several DiY projects mainly designed for use with very low power amps (i.e. monotriodes with 2A3). Looking back in the history we can mention Altec, JBL, Electro-Voice; at an impossible level of cost the 'esoteric' japanese projects (Audio Note, Audio Tekne etc.)

And find tweeters with that sensitivity IS a problem, at least conventional dome tweeters.
Good tw have an efficiency around 90 db, some can be defined '92' with some indulgency.
Excluding to multiply the number of units (that normally creates more troubles than it solves) there are 2 options: horn/compression tweeters or the Dr Heil's AMT. The latter is a great unit, but is expensive and very difficult to interface with a bass driver (let's say that all the system I heard, ESS first, always sounds as if the tw is one step ahead of all the rest)

Bass freq : it depends how low you want to go. If you accept a f-3 around 60-80 Hz the 95 db can be achievable reasonably easy, going deeper calls for a price in terms of volume and complexity (need of dedicated bass speaker).
Probably the best solution for a 95 db bass unit is to have a dedicated bandpass enclosure, whose cost and size is mainly defined by the lowest freq you want to reach. But this means a 3 way system.

Well, in summary I believe that your specs (95 db 1w/1m, 2 ways, no horns) are impossible to achieve with the components available on the DiY market, and I honestly believe that if somebody produces a well sounding 95db dome tweeter all the big names would be in queue to buy it!

Why don't step back and accept, say, 90-91 db efficiency?!

Hi epkpeng,

The figures quoted for the Audiom A range of speakers (7a2, 12ax, 15ax) are around the 95-96dB level. I can't comment, as I've only heard the old Kevlar and 13 inch Polyglass Audioms (they sounded good, but not for the cost). I think you might find it a bit hard to use these in anything other than a 3-way.

I did see an article posted a couple of years back on a fellow who used an R3, along with 4 Theil & Partner c95t12 units in an MMtMM. It was crossed at around 500Hz (I think). But I think the 12ax might be too big to use in that area of the midrange.

seriously, how much is the maximum amount you want to spend.... because there are plenty of drivers that have high sensitivity, you could get higher than 95dB that still sound good, if you want really really high sensitivity, for it to sound good and still handle power you will need to spend quite a lot of money, eg, all the studio monitors out there that are over 95dB.

I found a few high sensitivity drivers just off memory...

here is a dome, shallow horn tweeter from Peerless... it is 99dB

a morel tweeter shallow horn 97dB

also check this out.
Hi Epkpeng,

didn't knew this Raven ribbon tweeters, they look good but my impression is that their power handling is not that big.
If you plan to use a low power amp is ok, otherwise I fear they must be cut at 5-6 khz to avoid damage.
Maybe in that price range you may look at the 'big' AMT (sold at arond 500 Euro in Italy) who is around 98-100 db and can be x-overed around 1-1.5 khz.

In case you decide for a 3 way system, have a look at Audax PR17 midranges (http://www.e44.com/professi.htm) : they are well famed and does not cost 'an eye + an arm'.
Also their 10" PR240MO seems ok for an acoustic suspension (Q is 0.53) 2 way crossovered at 1.5-2khz

Other ideas you may find looking at the Ciare 'pro' catalogue, it's an Italian brand with an extremely good Q/P ratio (www.ciare.it), they should be distributed in Europe.


PS Andrew, the tw you mentioned are good (I used the Peerless in several projects) but are horn loaded dome tw, and epkpeng has excluded horns (I suppose for the coloured timbric and narrow dispersion). Audax and (I think) also Vifa has horn loaded domes in catalogue; accepting a horn loaded driver there is plenty of choice...

Hi there,
...and thank's for the answers!

Well...I wrote that money was not an issue...And ment it in a way that "what can we do if we neglegt the cost". Off course there is a roof for what I can pay...but lets say a figure; ~ $3000 for driver units (and XO, cabinet etc).

The tweeters are OK. I think I'll use the Raven R1 or R3 of nesecary! That should do it!

Beyma had som nice units, when it comes to sensitivity. Although, how will those dirvers sound toghether with Raven? Miss match?


The 'requirement' conserning 2 way is OK to change - a 3way design is OK, althogh not as desirable as 2-way (due to XO, cabinet etc..).

This one has a driver I could most definetly use! They are sold by Audio Note in Denmark...

Try Triangle. I've built MTM open baffle design using Triangle T160 and R1 and after 6 years still don't feel the need to change anything. Triangle midranges go very high and they could be actually used without tweeter. Sound beats Accuton and Focal units I used before. Recently I also bought PHL drivers and Raven2 which I try to use for another project. They all have efficiency around 93 dBs. Sourced from Orca or you could try distributor in France.
Recommendation: Fertin


you maybe should consider some fullrange chassis. You do no need to use them as fullrange (although biased me would recommend that :) )

For back-loaded horns consider the different Lowther chassis, they all are above 96db/W/m

For different applications consider Supravox from France but rumours have it their manufacturing quality control is not on the bounce. Anyway, they have quite a variety of differnt high efficiancy speakers.

For open baffle use, vented enclosures, closed enclosures but NOT for horns (diaphragm/VC/centering spider not airtight) consider the Fertin 8" drivers. Fertin has two 8"ers, one with a ferrite magnet rated at 94dB/W/m (FLB20MKII, ~US$600 a pair) and one with a field coil motor (FLB20EX, ~US$1500 a pair) rated at up to 98dB/W/m, depending on the field coil's supply voltage. Both drivers have profiled paper cones and both have a whizzer cone for the treble and a phasing plug, not a dust cap. Both drivers have a positive half roll rubber surround and a relatively high moving mass but the profiled paper cone acts as a mechanical filter so this should be ok.

I was seeking for a good fullrange driver myself (having had a Lowther Acousta for years and loving a fullranger's beauties) which is atleast covering 80Hz to 20kHz properly. I listened to the Fertin field coil thing and bought it at once, feeling that all my wet audio dreams were coming true (maybe w/o the utter low end). This listening at the dealer's place went over 5 hours and no listening fatigue at all, we were totally hooked.

You will not long for a tweeter with this speaker, the upper end is just a dream. In a baffle of 1m width and 1,7m height, you will probably not long for bass either, the bass appears fast and very slender but completely lacks the mud bass reproduction usually is heavily loaded with. But AFAIC, i know what can happen in the low end using a 1st class subwoofer and i want tohave my 20Hz !!!

So, what i am trying to put together at the moment is an open baffle subwoofer (faintly similar to the Linkwitz subwoofer but using a pair of 18" Beymas) and a stand for mounting the Fertin on its motor (too heavy to mount it at the basket only). The baffles will be easily replaceable, i already learned from an open baflle guru that the baffle has atleast as much influence as the driver and i will have to try out many.
The speaker will be bi-amped (AKSA 100W fot the subwoofer and my PP AD1 tube amp design for the Fertin, the amps having the speaker XO built in)

Manufacturing quality for the Fertins is superior, just gorgeous, like Altec in their best days.
Nice input...Althogh, I do not understand what you mean with "Big AMT from Italy"?!?! Any webadress?

I am a bit interested in a one way solution...off course... It will not be 'my product', but this is more a consultant mission! ;-)

I find it very strange that there are a LOT of drivers around 90dB, and then the proffessional driver units around 98-102dB...But where is the golden avarage? That is, some 95dB?

deeply confusingly....
Have you considered a line array, or the use of more than 3 drivers? Its a great way to boost sensitivity, and in my opinion, line arrays are the way to go. (I've converted ever since I heard a line array speaker.) If not, you can still use a high quantity of drivers, just not in the form of an array, and possibly in an open baffle to keep the cabinets very simple. I think the name of the speaker I'm trying to think of is the Phalanx, I'll try to poke around the web and find it.

Here's the Alon Phalanx: http://www.alonbyacarian.com/products/phalanx_b.htm

Note that it has low sensitivity, seeing as its a 4 way system. I was just referring to the arrangement of their midrange/midbass drivers as an alternative to line arrays.
The 'big AMT' is the top version of the ESS/Heil Air Motion Transformer, Italy is mentioned only because it is the only DiY market price that I know!

Unfortunately I could not find the tech sheets, but you can have some info here. If you never heard it, I think it is worth to listen to some system that uses it. Personally I don't like too much the smaller AMT (the non-dipole versions) but the big ones for me are great speakers.



To see the prices in Italy go here


and then pick ESS in the list at left.
Maybe try calling the guys at Digitex, don't know if they speak english but normally they are very kind and supportive.

Last Minute: here is a German shop who lists a lot of high sens. non-conventional tweeters.


and a German brand Eton who markets the small AMT (see under tweeters)



epkpeng said:
Nice input...Althogh, I do not understand what you mean with "Big AMT from Italy"?!?! Any webadress?

Sorry to interrupt your conversation, but:
What he means is an 'Air motion transformer'. Big heavy shunk of metal. Looks like a weird Electrostatic speaker.
This is probably the way to go if you still want HiFi/Hi-end sound quality. You can combine this AMT with two eg. to bass/midway drivers with say 90/91 db in parallel. This will cranck up your sound level with 6 db.

I am a bit interested in a one way solution...off course... It will not be 'my product', but this is more a consultant mission! ;-)

I find it very strange that there are a LOT of drivers around 90dB, and then the proffessional driver units around 98-102dB...But where is the golden avarage? That is, some 95dB?

deeply confusingly....

Why on earth do you want a 95 db speaker system :confused: . Do you life in a concerthall? This is quit a lot of sound your willing to produce.
Maybe, you can elaborate on this so i can understand what reason you have for building such a system???

If you want more info on this, just let me know (On or Off-forum).

Well...actually I have reveived a request from a company who builds tube amplifier. These will have some 7watts, whic have been calculated to match with ~95dB sensitivity.

My experiense is that HIGH Sens vs LOW(/er) Sens gives:
HIGH - musicality, rythm etc
LOW(/er) - detailed, soundstage 'hifi parameters'...

I also asked, because there are, to my knowledge, no drivers between the professional PA and the 'hifi drivers'(Scan Speak, Vifa, Eton etc).