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1. How do I connect to the terminals?

2. What is the difference between the main OW dome tweeter types?

3. Is the OW3 and OW4 just a colored version of the OWIIx? 

4. General information about main issues

5. Technical information about construction details

6. Replacement tweeter for Fried Products Speakers 
made throughout the period 1983 to 2003

7. A Review of The Hiquphon Series of Tweeters

















1. How do I connect to the Hiquphon dome tweeter terminals?

From the beginning the OW tweeters were intended for soldering.

If you can find banana plugs that fit into the terminal holes, then use them only as long as you are tweaking around testing and putting the units in and out of speaker crossover circuits.

When it comes to the final connection then please solder the wires to the terminals using a good quality tin to make sure you end up with an electrically safe and a mechanically strong connection. This is important, as musical quality depends on a safe no-loss connection.

As the terminals from the beginning were designed to be soldered, they are of course capable and very robust and they are not easily harmed while soldering the combination of wires and terminals. In fact you can solder and unsolder again and again without any problems. Damaging the plastic around the terminal does not influence the sonic quality of the tweeter at all, unless of course you keep heating with the solder iron until the iron penetrates the plastic housing (don't try to do that!).

How to:
Connect leads/wires to the terminals of a Hiquphon dome tweeter:

  1. Strip your wire (s) say half an inch (approx 12mm). 
  2. Stick the tripped wire ends down into the terminal (s) so that when hitting the bottom, approximately half of the stripped part stay outside the terminals.
  3. Gently press a good warm soldering iron tip towards the combination of your stripped wire and terminal and add/melt some quality soldering tin down into the cup terminal when the parts are sufficiently warm.
  4. Continue to heat until the tin melts down inside the terminal cup with the wire and join them perfectly when the tin has solidified.
  5. If you later want to remove the wire then simply heat the joint up again and draw out the wire.
  6. Remember, you can't harm the tweeter unless you let the soldering iron touch the terminal for a considerable long time.
  7. Just try to avoid touching the black plastic around the terminal, as it will melt. Still this is only a cosmetic problem that will not harm the function of the tweeter.
  8. Rewiring the tweeter later again is simply done by having the old tin to melt again in the cup terminal and then while the tin is floating, stick your wire into the melt and add some extra tin if necessary.

    We hope this explanation was useful to you. If not, then just email us and ask again further.
    Donít get nervous about this. We have never heard of customers being able to destroy a Hiquphon tweeter in the process of soldering the wire/terminal. So why would you be the first? 
    The terminals are VERY robust! You can connect to them by soldering again and again. No problem. Just always keep in mind, that the soldering iron should not be used longer than needed to melt the tin.

    Good luck with your speaker construction.  /OW


2. Explaining the differences between OW-types

It can be difficult to fully understand the differences in performance of our main OW types. The following was meant to be a descriptive explanation. 


OW3 / OW4 (also available as OW5 with classic black dome):

Let me state this first: OW3 or OW4 are NOT just colored versions of the OWIIx! 
This could easily be assumed, having studied the frequency curves. But no, they are not!

The basic construction of the OW3 and OW4 is the same as that of the OWIIx. So far so good. 
Different cone (diaphragm) and other materials inside, but a very different combination of coating substances on the dome! 
A different amount of coating too! A bit heavier and in fact more like the coating used with the OWI. 

As you may have guessed by now, coating is absolutely essential for the quality of a soft dome tweeter. 
In my opinion coating is THE far most important part of a soft dome tweeter (when properly done, that is :-). 
OW3 and OW4 are coated six times each! Standard OWI and OWIIx 2 times each. 
Each coating is accomplished using unique special selected coating substances added to achieve the important damping in the dome surface and of course to achieve the special colors as well.

The sound picture of the OW3 and OW4 does lean towards a softer and low distorted output in the lower frequencies than does the OWIIx. 

The right coating and damping is in fact the secret behind the high quality we offer! 
It takes most of a life time of experience to understand coating and damping in details.
Consistency really is a major problem, as all involved materials are soft and difficult to "measure" from batch to batch. Temperature, humidity and raw materials differ all the time. 
To control production of soft domes at the highest quality level does not come easy. 

During now 25 years Hiquphon have "learned by patiently doing "and now we just" know how to".


The OWIIx (upgraded from OWII to OWIIx in 2009) has lower moving mass and thus is "fast". 
When I say "fast" I am not talking of "sound speed", I am talking "fast to settle" from an impulse and thus ready earlier for the next signal coming in.
This means the voice coil is ready for the next pulse while being in a neutral position. 
In that way TIM (Transient Inter-Modulation distortion) is reduced more than otherwise. 
Thatís probably why some people find OWIIx more distinct in the upper end compared to the OWI.



The OWI and OW3/4/5 are both heavier damped than the OWIIx. Heavier damping contributes to perfect asymmetric behavior in the impulse response domain. After a pulse has been fired the dynamic moving mass is going to rest very fast without over swing (well damped). Again, settling is important here. A good speaker unit goes silent without ripple (multiple over-swing) after having responded to a pulse signal. This is especially important with tweeters as they reproduce the high frequency area in which the most important information about instrument positions in the complex sound stage is generated.


Further comments:

We can still supply small qty of the old now obsolite OWIII for repair purposes. 
These are available for those customers who absolutely MUST have the good old OWIII gold dome!

If you need more information regarding which type to choose, then please don't hesitate to email Oskar WrÝnding with further questions.

Kind regards 


6. Replacement tweeter for Fried Speakers...we still make them!

When the famous speakers from the old Fried Products Company were made years ago under the brilliant leadership of Mr. Irving M. Fried (Bud Fried), "The best tweeter in the world" (so Bud said whenever he had the opportunity and that happened quite often) was used. This tweeter was an early version of the Hiquphon OWII using magnetic oil in the air gap. 

Between 1983 and 1999 Fried Products used a 92mm version. From 2000 to 2003 our standard 94mm tweeter has been used in the newer Valhalla Speakers from Fried Products.

So, during quite many years we produced thousands of tweeters for various Fried Products speakers. Most of these tweeters still serve their owners faithfully. Unfortunately now then an accident may happen. 
For instance a child or grandchild with small curious fingers have been ďinvestigatingĒ the stiffness of the soft dome and pushed too hard :-(  Spare parts therefore now and then are needed as replacement. 

We still produce the original old types for replacement and sell them direct to any private owner of a pair of Fried Speakers. Simply email us, prepay the amount asked for, and your tweeters are flying the next day. 

Normally we only sell two units per order because we believe it to be important that you get a matched pair. 
So if one original unit is still playing and only one is off, we recommend that you change both and save the first still good one for eventual later use if another accident should happen.

Buying direct from Hiquphon is easy! You can simply prepay us through PayPal using your credit card. A bank transfer is of course an option, if that is what you prefer.

Original tweeter type names could be such as: D2092-9008-FS or D206-9008-FS or D2092-9008-01 and a few others. If you can take out the tweeter, you should find a label on the unit (if not removed for some reason) showing our name Hiquphon, the type name and a serial number.
Newer types (for Valhalla) may be named D2094-9008-F3B.

If you are uncertain of whether or not the tweeters in your Fried Speakers are produced by Hiquphon, you should email us and together we will find out what can be done. 

Finally we would like to mention, that quite a number of Fried Speaker owners have chosen to buy our special modified OWIIx, OW3 or OW4 as upgrades. Replacing the original tweeters with those new matched OW-types has generated quite many profoundly grateful emails to Hiquphon during many years already. 
Our saying: ďTo music with loveÖĒ is not empty words only.


A Review of The Hiquphon Series of Tweeters

by Jeff Bagby
November 2002

A while back Dave Ellis asked if I would be willing to evaluate and write a review on the Hiquphon tweeters that he was now authorized to sell. Having not yet heard any of these tweeters I, of course, jumped at the chance, but I told Dave it would take me some time to get around to doing it right. He said, no problem, take your time. Well, itís still long overdue, but here is my review of the Hiquphon tweeter. I know a lot of you are already familiar with these drivers, so I will write this review more for the person who is not as familiar, but may be very curious about trying one out. Hopefully, the information I provide will assist this person in making their decision, one way or the other, on whether one of these tweeters is right for their application.

I have a toddler at home (no, this is not a horror story of dome tweeters and little probing fingers), and I still have a clear concept of the phrase "hiccup on". Whatís this have to do with a tweeter review? Well, the first question anyone has about these tweeters is how to pronounce the name, and as I understand it sounds like hiccup-on with an "f" sound in the middle. Now you no longer have to deal with fear of trying to order something not knowing what to call it and wondering if the person on the other end of the phone is quietly snickering at your ignorance. Say "hiccup-phon" quickly. Now youíve got it.

Hiquphon is the name of a small loudspeaker parts company in Pandrup, Denmark. It is owned and managed by one man Ė Oscar Wroending, whose initials are the OW that you see on each of the model numbers. In fact, it is my understanding that Oscar does everything from own the company, to assembling and testing the tweeters, to sweeping the floor and turning the lights out.

Hiquphon makes four models of their tweeters, each based on the same basic platform Ė a 20mm soft dome tweeter recessed into a semi-horn designed face plate, and each using the same motor and cup assembly. The tweeters are aperiodically damped to a rear chamber. Each has a 94mm diameter flange with 3 mounting holes. The rear of the driver is completely enclosed in a plastic housing with terminals that consist of two clearly marked holes of 2.5mm diameter on the back of the cup.

This brings me to my only two negative comments regarding these tweeters. First, Iím not big on plastic faceplates. Theyíre just too easy to ding up. Look at the Seas Excel T25-001 tweeter, which is in the same price range. Now thatís a faceplate and cup assembly to be proud of, other manufacturers should take note. DIYers often change out tweeters or move them to other enclosures. We like designs that are durable. I know someone will say that the plastic is well damped or something like that, but Iím talking toughness here. The second thing I am whining about are those holes they call terminals in the back of the tweeter. A good connection is almost impossible short of soldering. Since I did not want to deface these tweeters during a review I had to resort to cramming twisted wire leads into the holes, and sometimes holding them in place with tape. This makes me think back to those Usher tweeters with the big ľ" blade terminals. These are the kinda terminals I like to see on a tweeter. I understand that Hiquphon's terminal holes are the result of the way the rear chamber is sealed, but stillÖ..

OK, Iím done whining. Because there are a number of perks when you get a pair of these tweeters that you do not get with most drivers. Did I say pair? Yes, I did. When you buy these they come as a matched pair packaged together in a single box. These tweeters have been matched to within +/- Ĺ dB from 2Khz to 20kHz (according to the literature). However, in addition to the assurance that they have been matched, each box comes with an actual SPL and Impedance plot of each of the tweeters in the box, each signed personally by Oscar Wroending. Also included is a small pamphlet giving all of the mechanical, electrical, and acoustical specifications for the tweeter model, and each tweeter has a nice sticker on it showing the model and serial number along with some of the specifications. Plus, the data on the pamphlet is very extensive, even to the point of giving the THD%, the acoustic center of the tweeter, and the X-max, among other things. These are all very nice touches that go well beyond what you will normally receive when you purchase all but the very finest of drivers, and sometimes not even then. My kudos to Oscar for such excellent and informative packaging.

The general specifications of these tweeters are as follows; they have a recommended frequency range of 2.5Khz and above using a specified 12 dB/oct. or higher electrical crossover. Fs for the different models runs between 850 and 900 Hz. The Re is typically 5.8 Ohms with a voice coil inductance of 0.03mH, the minimum impedance is about 6.5 Ohms at around 3.5kHz, and this is generally considered an 8 Ohm tweeter. The rated power is 100 Watts (using the recommended crossover slopes). The THD is listed as less than 0.15% at one Watt, above 2.5 kHz. Dome and voice coil diameter are both 20mm, with a one-way X-max of 0.9mm (a heck of lot for a tweeter), and the acoustic center is listed as 11.3mm behind the front of the tweeter (or 7.6mm from the mounting face of the flange).

As I mentioned there are four models and here are their basic distinctions from one another: The OWI, which is the most heavily coated and damped of the group. Because of this it also has the lowest sensitivity at 87 dB/W/M and flattest response of the bunch as well. The OWII, is the same tweeter as the OWI but with a lighter coating on the dome. It has a higher sensitivity at 90 dB/WM, but also begins to roll off a little higher in frequency than the OWI. Next is the OWIII, which is similar to the OWII, but has a different coating on the dome. Living here in Northcentral Indiana there has always been something special in any reference to the "Golden Dome", especially in November (Notre Dame football, sorry). But in this case the golden dome is the one on the OWIII. I am not familiar with the story behind the gold coating and I assume that it is primarily for cosmetic reasons, but it does change the response slightly as well as the sensitivity. The OWIII is a little lower than the OWII, coming in at 89 dB/W/M. The literature calls this one the "high end" tweeter, though, so I am not sure if it is only cosmetic. Finally, the fourth tweeter in the line is the OWI-fs. Unlike the other three tweeters, which do not have ferrofluid in the gap (did I leave that out?), this tweeter is the same as the OWI, but with ferrofluid in the coil gap. The basic difference between it and the OWI is a broader flatter impedance peak at resonance; otherwise the response curves and sensitivity are almost identical above 2kHz.

The choice of tweeter that would be best for your application will more than likely be based on the different sensitivities, the use of ferrofluid, and the color of the dome, but what about the sound? Is there a difference in the way these tweeters sound that distinguishes them from one another? Before I answer that question I would first like to compare the tweeters to some of the other tweeters that I had on hand.

When I performed the comparison of the Usher 9950 tweeter to the Dynaudio D260, and Seas Excel T25-001, I also included the OWII (which matched up well in terms of sensitivity). Later I compared the OWII to an Infinity EMIT tweeter listening to the upper register resolution. Here are my thoughts on these listening tests.

I spent most of my time listening to the following CD's:

"Bonnie Portmore" from the "Highlander Endgame" soundtrack

"Trumpet Spectacular" with Doc Severinsen and Erich Kunzel (CPO) on Telarc

"Jazz At The Pawnshop" on Proprius

"Ariel Boundaries" by Michael Hedges on Windham Hill

"Erkiology" by Steve Erquiaga on Windham Hill

In each case I tended to find the D260 to be the airiest of the group, almost to a fault. This came out the strongest on Bonny Portmore whose female vocal (Jennifer McNeil) is recorded a little "hissy" anyway (which is why I selected this CD for the test). A quick response check indicated that the Dynaudio has peak in response in the 10kHz region. This made D260 sound unnatural to my ears. The Seas had the strongest projection of her voice, and sounded the least "hissy", probably due to the slightly rolled off top octave of the T25, which measure very smooth otherwise. It sounded much more natural than the D260 did. The Usher was very clean in the upper vocals and tended to sound more natural than the other two tweeters. It had a little more air than the T25, but not quite as airy as the Dynaudio. Overall the Usher seemed a little more neutral than the other two, and this is mostly due to the top octave differences between the three tweeters.

However, when I played the OWII I was surprised how much it sounded like the Usher, which is a much larger tweeter. Of course, the lower registers were not as strong with the OWII, but overall the tonal balance through the rest of the treble and into the highest octave was similar between these two tweeters. The OWII actually sounding the most neutral of the bunch in terms of top octave balance to the rest of the treble. This is a hard thing for a most tweeters to get right, but the OWII nailed it hands down. The OWII measures almost dead-flat above 3kHz and sounds so natural and open that itís a little uncanny.

It is amazing how much difference there is in appearance between a 28mm dome and 20mm dome, and you would swear that the 20mm had to be even smaller than that just by looking at it. Therefore, it was certainly not surprising that the OWII did not have the brawn to keep up with the other tweeters much below 3kHz. Crossing over much below this point is almost too much to ask from such a small dome. I would limit it to 2.5kHz to 3kHz depending upon the crossover slope chosen. As I reported in the earlier review, the Usher and the Excel tweeter were excellent in the region around 2kHz in terms of power and dynamics. However, on the other end of the spectrum itís a different story. Although the Usher measures flat to 20kHz the size of itís dome means that as you move off-axis the response in the top octave drops off quickly. The OWII, on the other hand, due to itís small dome had much better dispersion of sound in the top octave. So, even though both tweeters measured flat to 20kHz on axis the OWII sounded much more open with a much smoother power response in the top octave. The highs on this tweeter are not only very natural and balanced, but seem to fill the room with a more open, natural balance than the larger tweeters were able to do.

I spent some time listening to Trumpet Spectacular and at times I was having a very difficult time pin-pointing the differences between tweeters. Each tweeter had it's own sound but these differences were subtle and at times hard to define. The easiest thing to pick out was always the extra sibilance from the D260. The OWII was always a little different sounding in the way it spreads the "air" out into the room. After a while I began to feel that this was "right" and I missed it whenever I listened to the other tweeters, which started to sound more closed in. To my ear the other tweeters sounded less like "natural sound" than when I played the OWII. I have heard this effect before because I lived with a Dynaudio D21/2 for a number of years, which was similarly open sounding. I wish I still had them so I could make a comparison with the OWII, but I had given them away a couple months before hearing from Dave. From my memory though, it seems that the OWII has a flatter, more natural balance than the D21 had, but I am working only from memory here. I have not heard the smaller Scanspeak tweeter myself, so I am not able to comment on it for comparison, but others have compared it favorably.

While listening closely to the brush strokes and hi-hat on the Jazz at the Pawnshop CD It was easy to tell that the OWII seemed to be a little more detailed and honest than any of the larger tweeters. It had the best resolution of detail and was very balanced in the top octave. In this area I felt it was best of these tweeters. (Having said this, I will add that with a crossover that lifts the top octave of the Seas Excel a little it really comes alive and sounds remarkable on this passage too, but the Hiquphon seemed neutral enough that it would not need any contour. It is very natural over its entire spectrum). The OWII is the hands down winner among these domes in resolution of detail and openness in the top two octaves.

It was here that I tried a head to head with the OWII and an Infinity EMIT tweeter. This did not work out well as a test. The two tweeters sound very different and require very different crossovers to sound right, making comparisons difficult. The EMIT has a rising response in the top octave which exaggerates the detail that the planar already reproduces. The OWII, on the other hand, is very flat and balanced. I have said it before, and I will say it again, planars resolve tons of detail, but I find them difficult to integrate with other drivers. The OWII resolves detail better than any of the other domes that I had on hand, but itís smooth response and excellent dispersion make it very easy to integrate. Because of this I would personally select the Hiquphon over a planar tweeter in an effort to build a balanced and integrated "musical" sounding speaker.

My final test involved listening for differences between the four models of the Hiquphon tweeters. This proved to be the most difficult test of all. By the time I was done I wished that Dave had only sent me one sample instead of four different tweeters. Wow, what a headache! However, I did discern some subtle differences and I will attempt to describe them the best than I can. I used the same CD for this entire test, kinda "listening into" the music over and over as I switched out the tweeters and set the levels. The CD was Steve Erquiagaís "Erkiology" on Windham Hill which is a nice Jazz CD with some really nicely recorded treble.

Using the OWI as a baseline here are my impressions of the differences between the models. The OWI is the flattest and smoothest sounding of the group. It is very neutral and well-behaved, and based on the response curve looks like it will extend a little lower in frequency than the other models, as it is flat down to 2kHz. The OWII is more sensitive by 3 dB, but most of this sensitivity is at the expense of response below 3kHz. The response of the OWII is gently rising up to 3kHz, levels off, then selves up a couple of dB at about 4kHz where it is flat out to 20kHz. Sonically though, this is not the only difference between these two tweeters. It seemed to me that the OWII has a bit more resolution of detail than the OWI had, possibly due to the extra coatings on the dome of the OWI adding mass-damping to the diaphragm. The gold domed OWIII had a response shape that was similar to the OWII except that it had a little more emphasis in the octave between 5kHz and 10Khz, and was not quite as flat in the top octave as the other two versions were. Because of this emphasis, the OWIII seemed to have a little more "bite" or "snap" to itís sound. It did not seem as neutral as the OWI, but it did seem to be a tiny bit more dynamic sounding because of the mentioned slight rise in response around 8kHz. Keep in mind that these differences are very subtle. I donít want to give the impression that one version is excellent and another is not. That is not the case. Each of these definitely sound like they are in the same family of tweeters, and they sound more alike than they sound like other tweeters, itís just that there are small, subtle differences that distinguish them from each other.

The fourth version is the newest one of the bunch. It is the OWI-fs, which is a ferrofluid version of the OWI. The only real difference that I can tell from this tweeter is that the ferrofluid produces a broad plateau rather than a peak at the resonance. The normal OWI peaks at about 16 ohms at resonance and the OWI-fs has a broader peak at about 10 ohms. This may make the OWI-fs easier to work with with some crossover topologies. Sonically, try as I might, I was unable to hear any difference between the sound of the OWI and the OWI-fs. They sounded exactly the same to me.

In conclusion, the tweeters from Hiquphon represent an extremely high level of performance for small dome tweeters. They excel in flatness of response, resolution of detail, and open, wide dispersion. If you are planning to build a speaker that has a tweeter crossover around 3khz or so, then I can not think of a tweeter I would recommend more highly. Above this frequency they do almost everything right. Personally, I love an open sounding tweeter that allows you to move around some without loosing the sweetspot. These tweeters give you that and more.

Because of itís 90db sensitivity, high resolution of detail, and flat extended response with a nice smooth roll-off on the low end, I really liked the OWII, and I am thinking of using it with some Dynaudio D76AF midranges that I have. This may be a match made in Heaven, or maybe just Denmark, but you get my drift.

If you would like to know more about these tweeters contact Dave Ellis at Ellis Audio and I am sure Dave would be glad to answer any questions you may have and even sell you a tweeter if you are in dire need of one or two.

Jeff Bagby

Kokomo, IN


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this page was last updated 10. February 2004 by OW