https://www.thomann.de/fr/bms_2250_...gpklpkFc6dAsIxFNOdmoInLbyR8TsHeAaAvVKEALw_wcB
700hz minimum.
I think you won't find a pa horn which goes below. For that you would need fency custom horns.
http://horns-diy.pl/horns/iwata/iwata-300/
700hz minimum.
I think you won't find a pa horn which goes below. For that you would need fency custom horns.
http://horns-diy.pl/horns/iwata/iwata-300/
Be interesting to see if the measurements of not just FR back that up. It's also very narrow at 50*.
They look really cool, but the polars aren't great.
The EV (Keele) Horns are still a top choice. Both 6040 and 9040 are worth investigating. The King around here these days is the Emilar EH153 with a throat extender down to a large format JBL.
Here is the EH153 used as midbass with an 8" B&C driver. The throat is 3.3" for the EC600 compression drivers. I made an extension to 2" for the JBL and use them 300 up to 9K.
https://www.diyaudio.com/community/threads/hlcm-horn-loaded-compact-monitor.287641/post-4959439
am waiting for the 4592 to arrive thanks Pano. I am thinking building a meh with 2 10".
and the next page a picture with the EC600. It looks to be a simlar design to my midbass horn (exponential/hyperbolic area expansion with conical vertical and horizontal making up the area expansion) but I use a 15" cone driver and have a much larger throat (only going to 400Hz ish). I recently have kept thinking about making a more powerful horn using multiple cone drivers feeding a common throat but we don't even approach the limits of the current horns.
Over the past month I tested the drivers listed below at a 1200hz two way 12db/oct crossover in the interest of understanding the characteristics of each for speakers which I’m building. I began this test using various horns I had on hand. I then tested all the drivers mentioned at 12’ listening distance unmated to horns, which yielded enough experiential information to determine what I liked and what I didn’t. After a month or so of experimenting this is the list of drivers tested in order of preference:
Beyma CP755ND
GPA Altec 288
BMS 4552
Faital HF108
Beyma CP22 (three way with AXI2050)
Beyma TPL200H
Celestion Axi2050
JBL 2453J — Mediocre
BMS 4591 — Mediocre
Faital HF206 — Mediocre
A simple conclusion from my tests is that a 3” diaphragm is the optimal size for a two way speaker design for normal to loud listening levels which is my preference based on my tests.
Larger diaphragms are more suitable for very loud listening levels as they are able to move more air, dissipate more heat and handle higher power though seemingly at the cost of resolution and extension. Thus far I’m lead to believe that I prefer a driver driver that can extend to 20,000khz over one that can be crossed below 600hz.
In every instance prefer the treble of the CP755ND to the various 1” drivers and tweeters which I tested. I attribute this to the powerful magnet and high quality diaphragm. At the crossover point of 1200hz which I tested at I very much prefer a two way implementation to a three way design. Another finding is that at this crossover point, in a living room at midfield listening distances, a wide dispersion horn, wave guide, and in some instances no horn, is preferable tonally a narrow throat horn with greater directivity.
Also, I wonder if the sensitivity rating which is often a reference parameter when selecting drivers is an incomplete picture of things. For example the BMS 4552 with a 1.7” voice coil and a sensitivity of 113db 1w/1m is not as loud or pronounced throughout its operating range compared with the CP755ND 110db 1w/1m sensitivity 2.8” voice coil. The question I have is whether the volume of air a driver displaces is taken into account when selecting a driver for an application. While at 1 meter the BMS will be louder, in a midfield implementation where sensitivity is a priority, the Beyma is a better choice in my observation. On that note, regardless of the intended application of either driver, I prefer the tonality and resolution of the Beyma to the BMS driver and all other drivers tested. It is a substantial step up from the rest in my opinion.
Next is to test the BMS and or B&C coaxial, and in addition some sub 8” midrange drivers to incorporate into a coaxial configuration with a compression tweeter. And to compare the 3 15” woofers which I have on hand — GPA 515 8ohm, Beyma 15P80FE 8ohm, Beyma 15G40 4ohm. I will eventually perform measurements of the drivers which I settle on for my project.
Some driver advancements that would be interesting to me are active drivers with directly coupled purpose built amplifiers, electromagnetic (field coil) compression drivers with integrated amplifiers and power supplies, electrostatic compression drivers, open back dipole compression drivers, perforated phase plugs, perforated horns, perforated horn infill, graphene diaphragms, mems arrays (horn loaded, spherical, etc.), singular driver-horn units where the phase plug and horn are a single continuous unit.
Beyma CP755ND
GPA Altec 288
BMS 4552
Faital HF108
Beyma CP22 (three way with AXI2050)
Beyma TPL200H
Celestion Axi2050
JBL 2453J — Mediocre
BMS 4591 — Mediocre
Faital HF206 — Mediocre
A simple conclusion from my tests is that a 3” diaphragm is the optimal size for a two way speaker design for normal to loud listening levels which is my preference based on my tests.
Larger diaphragms are more suitable for very loud listening levels as they are able to move more air, dissipate more heat and handle higher power though seemingly at the cost of resolution and extension. Thus far I’m lead to believe that I prefer a driver driver that can extend to 20,000khz over one that can be crossed below 600hz.
In every instance prefer the treble of the CP755ND to the various 1” drivers and tweeters which I tested. I attribute this to the powerful magnet and high quality diaphragm. At the crossover point of 1200hz which I tested at I very much prefer a two way implementation to a three way design. Another finding is that at this crossover point, in a living room at midfield listening distances, a wide dispersion horn, wave guide, and in some instances no horn, is preferable tonally a narrow throat horn with greater directivity.
Also, I wonder if the sensitivity rating which is often a reference parameter when selecting drivers is an incomplete picture of things. For example the BMS 4552 with a 1.7” voice coil and a sensitivity of 113db 1w/1m is not as loud or pronounced throughout its operating range compared with the CP755ND 110db 1w/1m sensitivity 2.8” voice coil. The question I have is whether the volume of air a driver displaces is taken into account when selecting a driver for an application. While at 1 meter the BMS will be louder, in a midfield implementation where sensitivity is a priority, the Beyma is a better choice in my observation. On that note, regardless of the intended application of either driver, I prefer the tonality and resolution of the Beyma to the BMS driver and all other drivers tested. It is a substantial step up from the rest in my opinion.
Next is to test the BMS and or B&C coaxial, and in addition some sub 8” midrange drivers to incorporate into a coaxial configuration with a compression tweeter. And to compare the 3 15” woofers which I have on hand — GPA 515 8ohm, Beyma 15P80FE 8ohm, Beyma 15G40 4ohm. I will eventually perform measurements of the drivers which I settle on for my project.
Some driver advancements that would be interesting to me are active drivers with directly coupled purpose built amplifiers, electromagnetic (field coil) compression drivers with integrated amplifiers and power supplies, electrostatic compression drivers, open back dipole compression drivers, perforated phase plugs, perforated horns, perforated horn infill, graphene diaphragms, mems arrays (horn loaded, spherical, etc.), singular driver-horn units where the phase plug and horn are a single continuous unit.
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I assumed that's the case at this point in time given that companies like Textreme, Eminence, Purifi, Satori etc and the new Faital HF1460 are relying on more standard carbon fiber formulations for their diaphragms. Perhaps someday someone will discover something. I know so little about the technology to say much more than that haha.
A290 horns. I have some adapters (the Beyma on the left in the photo is sitting on one of them) though I wasn't particularly stringent with my selection of horn entry angle selection relative to the driver. Upon receiving the GPA Altec 288s and realizing the mounting hole size and format is different and that I didn't have the proper horns is when I started testing the drivers without horns and determined that this gave a pretty good impression of the general tonality. The finding was that the majority of drivers were either lacking in mid range (1" drivers) or treble (1.4" and 2" drivers). The top four on my list were the most competent as far as extension. Not on the list but also tested were the Faital HF1440, B&C 550TN and 980TN. The former had some objectionable crap in the upper mids and treble compared with the others, and the ladder two were relatively unimpressive.
If building a small system I would opt for an HF108 or BMS 4552 in a very wide dispersion horn with a conservatively high crossover point as I imagine they'd perform better than most hifi or pro tweeters. For a full size system the CP755NDs are the best option in my opinion as I've stated. I'm sure the TADs are excellent though I like the idea of using and experimenting being able to tamper with a product that is readily available and not scarce or exorbitant in price. The TAD's feel kind of obsolete despite their presumably outstanding performance. I'll probably pick up a pair some day as I remain curious. That said I think the very small, dense and well damped enclosure, and short exit throat of the CP755NDs in particular lends to improved clarity and the ability to experiment with wider dispersion designs. Older drivers like the Altec 288s and TADs with longer throats are more optimal for projecting sound long distance. In my experience trying different horns, I find in a smallish listening space greater dispersion yields more enjoyable sound than greater directivity.
If building a small system I would opt for an HF108 or BMS 4552 in a very wide dispersion horn with a conservatively high crossover point as I imagine they'd perform better than most hifi or pro tweeters. For a full size system the CP755NDs are the best option in my opinion as I've stated. I'm sure the TADs are excellent though I like the idea of using and experimenting being able to tamper with a product that is readily available and not scarce or exorbitant in price. The TAD's feel kind of obsolete despite their presumably outstanding performance. I'll probably pick up a pair some day as I remain curious. That said I think the very small, dense and well damped enclosure, and short exit throat of the CP755NDs in particular lends to improved clarity and the ability to experiment with wider dispersion designs. Older drivers like the Altec 288s and TADs with longer throats are more optimal for projecting sound long distance. In my experience trying different horns, I find in a smallish listening space greater dispersion yields more enjoyable sound than greater directivity.
I prefer the CP755NDs not mounted to the horns as some of the treble extension is lost when mated the horns. Unmounted to the horns they sound so open and extended and perfume the room with sound in a way that isn't the case when mounted to horns. The Celestion AXI2050s benefitted from being mounted to the A290s. I tested those in a two way and three way configuration. In a two way they are not remotely sufficient. Anyone claiming otherwise is deaf no offense. There is zero extension. In a three way they sounded good with both the Beyma CP22 and BMS 4552 with a 6300hz crossover in both instances. I prefer the treble of the CP755ND to either of those two drivers though. Crossed at 1200hz the CP755ND as a two way is better than all other configurations to a substantial degree. That said the AXI2050 has exceptionally clean mids but is also generic, sterile and unmusical compared with the CP755ND and Altec 288. It feels prosumer compared with those two. It also suffers from some enclosure resonance. I think the large cumbersome seemingly cavernous/hollow enclosure of the AXI2050 is an engineering flaw. I wasn't as impressed as I expected to be. At a 300hz crossover it may be a different story. I'm more interested in an open baffle synergy horn style design with some small drivers than the AXI2050 crossed low with a supplementary tweeter whatever that may be.
I intend to open up the CP755NDs and run them as dipoles if possible -- maybe necessitating fabricating an alternate enclosure out of wood. And also compare with the aluminum diaphragms available for these drivers. I would like to install some very subtle radial waveguides on the CP755NDs to provide some fit and finish. I think the more bulk that is added the more the magical quality of the raw CP755NDs that I'm observing may be lost.
I intend to open up the CP755NDs and run them as dipoles if possible -- maybe necessitating fabricating an alternate enclosure out of wood. And also compare with the aluminum diaphragms available for these drivers. I would like to install some very subtle radial waveguides on the CP755NDs to provide some fit and finish. I think the more bulk that is added the more the magical quality of the raw CP755NDs that I'm observing may be lost.
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