I tried 4 prototypes using Tractrix rectangular horns. Please search my other threads as I posted measurements. Bottom line is this driver struggles to reach 2kHz xo as I intended. Otherwise very good.
I have not given up on it but I'm building the midbass section first and lacking much time so progress is veery slow. Will also buy the added amp and experiment with the midbass and tweeters and a couple midrange prototypes.
Hey guys
What do you think about this driver for a midrange horn?
Oberton 8NMB250v4
8NMB250v4
250-4kHz using a phase plug and exponential horn profile with a 3000Sq cm large mouth
This was my first choice and to push it to 5kHz
PD.103NR1
PD.103NR1 | Precision Devices Loudspeakers
What do you think about this driver for a midrange horn?
Oberton 8NMB250v4
8NMB250v4
250-4kHz using a phase plug and exponential horn profile with a 3000Sq cm large mouth
This was my first choice and to push it to 5kHz
PD.103NR1
PD.103NR1 | Precision Devices Loudspeakers
Last edited:
Ye olde post, but Scott L might be excited to discover that this feature set exists: a 6 inch driver, with "bullet" phase plug, 11g moving mass, copper sleeve.
Acoustic Elegance TD6M-8 - 6" Mid-range
Acoustic Elegance TD6M high efficiency midrange/midbass driver
Lowther in midrange horn
I am using Lowther DX65s in conical 60 x 30 midrange/high frequency horns. Their frequency response is 500 to ~7000 hz. To flatten the peak at higher frequencies, I use an inductor, but this rolls off the higher frequencies from the Lowther. Right now I am using a ribbon for supertweeters, but I will try to add back in the high frequencies from the Lowther instead.
Sounds great!
Retsel
I am using Lowther DX65s in conical 60 x 30 midrange/high frequency horns. Their frequency response is 500 to ~7000 hz. To flatten the peak at higher frequencies, I use an inductor, but this rolls off the higher frequencies from the Lowther. Right now I am using a ribbon for supertweeters, but I will try to add back in the high frequencies from the Lowther instead.
Sounds great!
Retsel
Thank-you, for that. But, what we need is a driver with more BL than moving mass. In this manner, and of juggling the necessary parameters, we can end up with a very light-weight cone with a powerful magnet, and a rising response curve. When said cone is mounted on a horn of sufficient and adequate size, the horn lift will flatten the response. This type of marriage can sound, really, really good, but as with all things audio--there is a compromise. We need to cone/horn combination to reach high enough in frequency that we either 1) don't need a tweeter (LOWTHER DX series) or
2) are able to cross high enough to the tweeter that the location of the tweeter being above the horn, is not noticeable. IOW, 6K or higher. The other drawback is the beaming that will occur on said horn of sufficient size. It requires "head-in-a-clamp" listening position, bit it will be one hell of a nice experience for ONE PERSON.
None-the-less, the TD6 might work out well, in a smaller sized horn, which in turn will limit the low frequency range. Worth a try. Thanks for the post.
"Thank-you, for that. But, what we need is a driver with more BL than moving mass."
The BEYMA 6MCF200Nd is exactly this - 16g, 19.2 BL.
However, in practice, on a horn, it appears to die at 3kHz:
Limmer Horn 042ba - 6" und 1" Horn - Beyma 6MCF200ND - Lautsprecher-Technik
The RCF is the same.
RCF MR8N301 8" RCF closed back midrange speaker - RCF 8" MR8N301 Speakers - RCF MR8N301 300 watt 8" sealed midrange speaker. RCF MR8N301 mid-bass speakers available now.
These guys aren't dummies, so I guess a DIY dude would struggle to do better.
"are able to cross high enough to the tweeter that the location of the tweeter being above the horn, is not noticeable. IOW, 6K or higher"
Small-ish cone drivers can do that pretty easily, if you are OK with less efficiency / using a bit of HF boost.
Some chunky compression drivers can do approx 400-6kHz at >105dB per watt. I have a single old Community M200, which I bought based partly on POOH taking it up in this thread. I tried it on a cheap 2" horn that I modded / extended, and it measures pretty well to 6k, I somehow got more HF bandwidth than is shown on the spec sheet: image attached.
I didn't experiment much with it. I assume DSP would be essential if you wanted to use it to 6kHz.
Yesterday I found another orphan M200 on ebay ($60), so I should eventually have a pair.
B&C + BMS make modern drivers that seem equivalent / better.
B&C DCM50 2" Neodymium Midrange Compression Driver 8 Ohm 4-Bolt
The BEYMA 6MCF200Nd is exactly this - 16g, 19.2 BL.
However, in practice, on a horn, it appears to die at 3kHz:
Limmer Horn 042ba - 6" und 1" Horn - Beyma 6MCF200ND - Lautsprecher-Technik
The RCF is the same.
RCF MR8N301 8" RCF closed back midrange speaker - RCF 8" MR8N301 Speakers - RCF MR8N301 300 watt 8" sealed midrange speaker. RCF MR8N301 mid-bass speakers available now.
These guys aren't dummies, so I guess a DIY dude would struggle to do better.
"are able to cross high enough to the tweeter that the location of the tweeter being above the horn, is not noticeable. IOW, 6K or higher"
Small-ish cone drivers can do that pretty easily, if you are OK with less efficiency / using a bit of HF boost.
Some chunky compression drivers can do approx 400-6kHz at >105dB per watt. I have a single old Community M200, which I bought based partly on POOH taking it up in this thread. I tried it on a cheap 2" horn that I modded / extended, and it measures pretty well to 6k, I somehow got more HF bandwidth than is shown on the spec sheet: image attached.
I didn't experiment much with it. I assume DSP would be essential if you wanted to use it to 6kHz.
Yesterday I found another orphan M200 on ebay ($60), so I should eventually have a pair.
B&C + BMS make modern drivers that seem equivalent / better.
B&C DCM50 2" Neodymium Midrange Compression Driver 8 Ohm 4-Bolt
Attachments
Last edited:
These guys aren't dummies, so I guess a DIY dude would struggle to do better.
Please see the link. It more closely resembles what I was describing in my earlier posts. 1.4T ---- BL 8 -----mass 6
Just because a person is a DIY does not make them necessarily good, or bad. It just shows a willingness to build/and/explore with one's own initiative.
https://www.parts-express.com/pedocs/specs/294-650--bc-6pev13-spec-sheet.pdf
Please see the link. It more closely resembles what I was describing in my earlier posts. 1.4T ---- BL 8 -----mass 6
Just because a person is a DIY does not make them necessarily good, or bad. It just shows a willingness to build/and/explore with one's own initiative.
https://www.parts-express.com/pedocs/specs/294-650--bc-6pev13-spec-sheet.pdf
"Please see the link." ...and 3rd party tests, with more info, are here. It doesn't seem obviously better than the drivers without phase plugs. The HF is lumpy (not a smooth rise), and doesn't get to 6kHz.
high-efficiency_midrange-drivers
This is another driver of a similar type:
https://www.scan-speak.dk/datasheet/pdf/15m-4624g00.pdf
The official spec sheet FR plots are good, it has a phase plug, it performs well on (Vance Dickason's) 3rd party tests, and the on-axis response is pretty extended.
https://www.scan-speak.dk/datasheet/reviews/15M-4624G00-VoiceCoil_2012-8.pdf
....so it looked good to me. I got three of them, my idea being that I could do non reversible mods on one, and still have a stock pair to use.
Sticking one on a large horn with 2" throat, there is lots of gain, but only over a ~2 octave range. In this configuration, it needs a dose of EQ to act as a wide band driver. I am yet to try it on a larger throat. My expectation is that a bigger, asymmetric throat (e.g. 5*10cm) will give me another octave of HF.
I will be surprised if I ever get them flat to 6kHz (without eq). What I'm expecting / hoping for is lots of gain 300Hz-1500Hz, and then another octave or two of lower (but smooth) response that is easy to EQ.
"Just because a person is a DIY does not make them necessarily good, or bad"
Sure, but even for a good DIY tweaker, getting a 6" to give 3kHz extra HF (compared to what professionals achieve, on a horn with a simple phase plug) will be a struggle.
high-efficiency_midrange-drivers
This is another driver of a similar type:
https://www.scan-speak.dk/datasheet/pdf/15m-4624g00.pdf
The official spec sheet FR plots are good, it has a phase plug, it performs well on (Vance Dickason's) 3rd party tests, and the on-axis response is pretty extended.
https://www.scan-speak.dk/datasheet/reviews/15M-4624G00-VoiceCoil_2012-8.pdf
....so it looked good to me. I got three of them, my idea being that I could do non reversible mods on one, and still have a stock pair to use.
Sticking one on a large horn with 2" throat, there is lots of gain, but only over a ~2 octave range. In this configuration, it needs a dose of EQ to act as a wide band driver. I am yet to try it on a larger throat. My expectation is that a bigger, asymmetric throat (e.g. 5*10cm) will give me another octave of HF.
I will be surprised if I ever get them flat to 6kHz (without eq). What I'm expecting / hoping for is lots of gain 300Hz-1500Hz, and then another octave or two of lower (but smooth) response that is easy to EQ.
"Just because a person is a DIY does not make them necessarily good, or bad"
Sure, but even for a good DIY tweaker, getting a 6" to give 3kHz extra HF (compared to what professionals achieve, on a horn with a simple phase plug) will be a struggle.
Last edited:
trial and error
I have achieved superb results with an eight inch full-range/wizzer-cone/with phase plug on a very large, round horn with a 6 inch throat.
But, not ruler flat. And, there is a price to pay. As per usual, there are compromises involved. Large, round horns bring the performers into the room.
The price to pay is considerable beaming and some listeners could NOT tolerate the horn colouration.
It's not so much that "we are there" but rather, "they are here". What I got was an uncanny sense of live dynamics and realism.
In some of your examples, you are showing test results of a driver on a flat baffle. Of course, all things change when the same driver is placed on a horn, and it will certainly vary from horn-to-horn.
To me, small throats have a certain "pinched" sonic signature. Having said that, I still would not discard the notion of a 2 inch throat entirely, because I have not heard every single horn on the planet.
You seem to have done quite a bit of home work already. I have found that if I go back and re-read some of the material (several times over, in fact) I will pick up on tidbits I missed before. A good paper to study is Bruce Edgar's article. There is a link to it on Volvo-Tretter's website.
So, in the end, it's really all about trial and error. I've been doing this for almost 50 years and I have made far more errors, than I have achieved success. It only took Edison 1000 tries.
I have achieved superb results with an eight inch full-range/wizzer-cone/with phase plug on a very large, round horn with a 6 inch throat.
But, not ruler flat. And, there is a price to pay. As per usual, there are compromises involved. Large, round horns bring the performers into the room.
The price to pay is considerable beaming and some listeners could NOT tolerate the horn colouration.
It's not so much that "we are there" but rather, "they are here". What I got was an uncanny sense of live dynamics and realism.
In some of your examples, you are showing test results of a driver on a flat baffle. Of course, all things change when the same driver is placed on a horn, and it will certainly vary from horn-to-horn.
To me, small throats have a certain "pinched" sonic signature. Having said that, I still would not discard the notion of a 2 inch throat entirely, because I have not heard every single horn on the planet.
You seem to have done quite a bit of home work already. I have found that if I go back and re-read some of the material (several times over, in fact) I will pick up on tidbits I missed before. A good paper to study is Bruce Edgar's article. There is a link to it on Volvo-Tretter's website.
So, in the end, it's really all about trial and error. I've been doing this for almost 50 years and I have made far more errors, than I have achieved success. It only took Edison 1000 tries.
I don't know if these have been mentioned here. I saw them on a thread here on DIY Audio. They do 300Hz - 3kHz:
Sonitus MR8XT Mid Range Horn with high efficiency 8" driver
Sonitus MR8XT Mid Range Horn with high efficiency 8" driver
I agree with you on the problem with beaming, and I noticed this with the Lowther DX drivers mounted in front horns/waveguides (and actually this issue is not limited to front horns/waveguides).
But because Lowthers are designed to fit a diffuser, I created a light bulb base which screws into the place that the diffuser screws into the Lowther diffuser location so that I can try different light bulbs as diffusers for the Lowther drivers. What works well for me is a par 38 shaped light bulb, which is sort of a funnel shape. (see 45 conical phase plug on this webpage: Audioprogress) In my listening experience, none of the stock Lowther phase plugs/diffusers work as well (although some swear by the light bulb diffusers that Lowther sells). This eliminates the beaming of the high frequencies that occurs with the whizzer, and thus improves the power response. The center position is still the prime location for listening, but other seats are more enjoyable this way, at least in the treble - the bass is another matter due to room modes....
Retsel