Volvotreter has this Edgar Tractrix 300Hz midrange horn: http://www.volvotreter.de/downloads/300hz_d54_horn.pdf
It's in line with your numbers above: 15.4"x10.5"=165 in^2.
This horn, however, was built for a Dynaudio D-54, 2" driver. Would the horn dimensions change if I used a 6.5" cone? Naturally the throat would need to change. But the horn itself?
I believe this horn is being used from 500 to 5000Hz.
If you plan to construct a custom wooden horn for a 6" - 6.5" cone speaker, you might consider matching the 80degree horizontal and 30degree vertical dual radial polar pattern of the TPL-150H horn which you already own. The Horn Response Simulator would allow you to use the T/S parameters of your selected speaker. Easy sim. Horn-Experts would help you. There are a couple spreadsheets which help layout the wood cuts+shaping.
A second path might be to find a proven 6" - 6.5" speaker + bi-radial horn design which comes close to your goals and build it.
A third path might be to find a JBL dealer in your country and purchase JBL's plastic PT waveguides and either JBL 2169H 8" Woofer CMCD-82H, or 6.5" JBL 165H. Spend your money on a proven design instead of investing your shop time.
Personally, if I wanted to experiment down this path I would purchase the USA JBL CMCD-82H + phase plug + PT waveguide and accept a steep crossover point "close" to 2,000Hz.... may 1,800Hz if necessary.
Scott,
did you see the new production of PHL Audio with phase plug ?
Unfornatully, it seems it's more and more difficult to buy a PHL driver for DIY ! I went to Paris in a HP shop, they just sell now 2 old models and say the factory don't want to sell bellow 20 units... not so much diyers enough in France to allow shop to sell them; and not smart enough people at the factory to allow Internet shop... the famous designer of PHL Audio sold his participation several years ago if my understanding is correct... a pity, often good artisanal product in France but poor hability to sell !
But the AH horns in Australia with which you have a shematic to cut the throat at the apex size you want, I'm not aware of horns with more than 2" for mids and more ! Azurahorn makes JMLC horns which allow to choose the size of the Apex, 5" for instance which can be good for 6" drivers ????
I'm also thinking to TAD-4001 horn like with phase guide for treble near the Apex like the genuine design of its better japoneese brand brother for studio.... but all expensive and made only for compression !
It should be fantastic to have a 90x40° for a 4" to 6" cone driver
, but my understanding is the tratricx design seems better to "amplify" cone driver efficienty ! Maybe the round JMLC could be the best of two world, I dunno ! But for home environment, such driver could have 100 dB efficienty and 115 to 120 dB peak for classical music or jazz without distorsion due to the low cone moving if I understood the measurement xrk971 made with the ScanSpeak 10F/8 or some Vifa like the the TC9 (Weltersys seems happy also with it in a synergy : and it's full range.)But same story : most of bi-radial are not happy below 700 Hz not giving a so good result (at list with 2" compression); direct cone radiation or trough synergy ports seems better for the important snappy and light range : 100 around 800 Hz.... old story
Scott,
did you see the new production of PHL Audio with phase plug ?
Unfornatully, it seems it's more and more difficult to buy a PHL driver for DIY ! I went to Paris in a HP shop, they just sell now 2 old models and say the factory don't want to sell bellow 20 units... not so much diyers enough in France to allow shop to sell them; and not smart enough people at the factory to allow Internet shop... the famous designer of PHL Audio sold his participation several years ago if my understanding is correct... a pity, often good artisanal product in France but poor hability to sell !
Did you try:
PHL Audio 1280 (8Ohm) - Cône Bicône / LF MF - Haut-parleurs
I bought my Audax HM210Z10 there.
Ah, thanks. Toutlehautparleur seems to trust the french market and seems to be serious. Brick&Mortar shop,not so reactive but for the PA speakers world (more active here than the "audiophile" one).
More Horn or Not
SWAG: a good horn to pass say 250 Hz will have a mouth perimeter of 54" (14" Sq. plus lips to reduce reflectance). If this is way too big, then go with direct radiator(s). MTM (d'Appolito) configuration may be a path to take that allows use of smaller dual drivers to meet the same volume displacement ([Vd]=[Sd]*[Xmax]) requirement, instead of using just one driver with a larger [Sd].
The use of a DSP head end and dedicated power amps puts you way ahead in the loudspeaker system design game. Do not forget to use a dc blocking capacitor in each drive circuit of the HF and MF units.
If your pockets are that deep, then go the extra mile with the BMS drivers and have fun just building your own horns. Here keeping the speech range intact is a good design tack if you can accommodate a generous horn size required. Here I would use a lipped OS (Freehafer/Geddes) horn that transitions from circular to rectangular in such a manner as to emulate the radiating pattern of the ribbon tweeter. Note: driver exit and horn entry slopes should match.
Regards,
WHG
SWAG: a good horn to pass say 250 Hz will have a mouth perimeter of 54" (14" Sq. plus lips to reduce reflectance). If this is way too big, then go with direct radiator(s). MTM (d'Appolito) configuration may be a path to take that allows use of smaller dual drivers to meet the same volume displacement ([Vd]=[Sd]*[Xmax]) requirement, instead of using just one driver with a larger [Sd].
The use of a DSP head end and dedicated power amps puts you way ahead in the loudspeaker system design game. Do not forget to use a dc blocking capacitor in each drive circuit of the HF and MF units.
If your pockets are that deep, then go the extra mile with the BMS drivers and have fun just building your own horns. Here keeping the speech range intact is a good design tack if you can accommodate a generous horn size required. Here I would use a lipped OS (Freehafer/Geddes) horn that transitions from circular to rectangular in such a manner as to emulate the radiating pattern of the ribbon tweeter. Note: driver exit and horn entry slopes should match.
Regards,
WHG
But the AH horns in Australia with which you have a shematic to cut the throat at the apex size you want, I'm not aware of horns with more than 2" for mids and more ! Azurahorn makes JMLC horns which allow to choose the size of the Apex, 5" for instance which can be good for 6" drivers ????
I'm also thinking to TAD-4001 horn like with phase guide for treble near the Apex like the genuine design of its better japoneese brand brother for studio.... but all expensive and made only for compression !
It should be fantastic to have a 90x40° for a 4" to 6" cone driver
But same story : most of bi-radial are not happy below 700 Hz not giving a so good result (at list with 2" compression); direct cone radiation or trough synergy ports seems better for the important snappy and light range : 100 around 800 Hz.... old story
Manninen pointed to Achenbach in Germany, which is what I was going to suggest considering you are in EU. Moreover, look at the kits Achenbach sells. He builds with TPL-150 and PHL. Son and Son XL, if I recall correctly. Dieter Achenbach recommended to me using an 8" PHL (2520, I think) as midarnge, in the context of direct radiators. In his view one 6.5" looks odd with the TPL and MTM with 6.5" gets you into trouble with lobbing.
One things that holds me back with PHL is that they don't publish curves and the few I have seen, like Achenbach's measurements, usually display ripples in the impedance. Like what's going on around 1.5kHz with the 1280 Manninen linked to.
FWIW, Overkill (Dereck) also recomended a PHL midrange (6.5" in that case) to match a TPL.
Scott,
What is your view regarding and 300Hz Edgar Tractrix type with a cone such as the PRV Xrk posted on, B&C 6PEV13, or your PR170? Where do these fall short in your view?
I've been looking into the PT guides a bit. At this point it's not clear to me how good these are for home audio.
Not saying they aren't good, but came across a couple of comments suggesting they were developed with PA goals in mind. Additionally,
- Pooh wasn't using them with his CMCQ-81H (he was using a conical horn), plus he recommended the CMCQ-61 for my purposes so I could comfortably cross over at 2-2.5kHz, considering I have some leeway in the bottom end of that driver.
- Interestingly JBL is not using those PT guides in their Everest or other top line speakers they make.
- This last weekend Manninen tried a PT horn with a B&W FST driver. The configuration he initially tried didn't work very well (TPL placed inside the PT horn). I'll wait for his further work to try and get a better understanding of the PT horn potential.
And it would be more fun to build the horn than to buy an ugly PA horn
The B&C 6pev13 is quite a bit better than the Pr170mo in a horn- as direct radiator the Audax is excellent. The JBL cone compression drivers are really high output and will have better power response (phase plug) in a horn than the 6pev13. The 8" CMCD will run in to trouble crossed that high so the smaller driver makes more sense. I really like the B&C overall (use 4" round throat) and for the money I would start there. With a 4" throat you can always go to the JBL to see what you may be missing. I tried to buy the JBL waveguides 3 times and the other parties never completed the sale!? weird - In a 300 Hz tractrix horn I think the best you'll get out of any of these is 550-600 Hz.
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Looks like JBL has enough money so they don´t have to sell more stuff fast anymore
My new Loudspeaker Systems – Great Plains audio - Page 7
Like me, this guy waited 4months or decades his products.
Yesterday i turned my room around once again and took TPL out of horn, don´t put anything to the horn.
My new Loudspeaker Systems – Great Plains audio - Page 7
Like me, this guy waited 4months or decades his products.
Yesterday i turned my room around once again and took TPL out of horn, don´t put anything to the horn.
I like the Edgar just fine. I was waiting for an answer from Line Source as to an example of a good bi-radial meant for a 6-6.5 inch.
Senior POOH: I have a pair of the Audax PR-170zo that I wish to construct an
Edgar type mid horn for. I was going to use a throat much larger than even a 4 inch. I was thinking of a 6 inch throat to match the cone area. With a very large mouth, because I want to get down to 250Hz. Thanks !
The PR170MO is OK up to 1.4 / 1.5K in a horn. Never had the ZO. The MO loses it magic in a horn and sounds a bit dead
The B&C 6PEV13 does 2.3K pretty well with a 4" throat, it is very dynamic
The JBL LE5 will go to 4K but falls behind in dynamics but in a small system where dynamics aren't that important it may be the winner of the three
The little Faital M5n1280 is like a LE5 on steriods
The PR170MO is OK up to 1.4 / 1.5K in a horn. Never had the ZO. The MO loses it magic in a horn and sounds a bit dead
The B&C 6PEV13 does 2.3K pretty well with a 4" throat, it is very dynamic
The JBL LE5 will go to 4K but falls behind in dynamics but in a small system where dynamics aren't that important it may be the winner of the three
The little Faital M5n1280 is like a LE5 on steriods
Interesting. The Faital M5N has an aluminum basquet, much like the JBL CMCQ, which I guess helps towards coupling it with a horn. Looking at their website I found there is an 8 Ohm version (M5N8-80) and the 12 Ohm version you mentioned. Both look good. The 12 Ohm has very low Le of 0.15mH vs 0.22mH for the 8 Ohm version (still very low).
Frequency response looks good, although the 12 Ohm displays a dip around 2kHz and from that point of view the 8Ohm looks better.
Also of note is neither this one nor the LE5 have phase plugs, vs the 6PEV and the PR170zo that do.
Do you happen to have measurements of the Faital Pro in a horn?
FWIW, below is a table with the better looking 5-6.5" drivers. I have a similar one for 8". The darker the shading the better.
