I modified the crossover based on driver measurements. Now the crossover points are 200, 600 and 4000 Hz, all L-R 24. I removed all the EQ (except for a 6db bass boost at 30 Hz) and adjusted balance just by relative levels.
The resulting sound is much more natural, definitely an improvement. There is an overall slight tilt towards the HF. When I tried CD compensation before, it always turned out too trebly at higher volumes.
Now I definitely need a better HF horn and amp.
The resulting sound is much more natural, definitely an improvement. There is an overall slight tilt towards the HF. When I tried CD compensation before, it always turned out too trebly at higher volumes.
Now I definitely need a better HF horn and amp.
I have found a relatively inexpensive driver and CD horn combo - RCF HF950 + BMS4554 or 4555 - they have a polyester diaphragm and if I limit the power to 5 W (SE tube amp), I can go as low as 400 or 500 Hz. Full set for less than 400 USD. I call that a bargain
I might be actually able to hang the HF horn inside the midbass horn and it would work also as a phase plug I imagine
I might be actually able to hang the HF horn inside the midbass horn and it would work also as a phase plug I imagine
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A small update - I finally have some proper horns for the Beyma drivers, the very cheap KHD164. They look really nice and fit well. It does not surprise me that they also measure well:
Definitely an improvement, also in sound, now the treble is just more natural and extended. I will need to do some polar measurements since the pattern in the description sounds too wide to me.
I also tried another ultra cheap horns with a wider pattern than the existing ones - ARB2. The JBL2445J I have are 3dB less sensitive, but the high end is a bit more extended. It is supposed to be a clone of JBL2380
For comparison, here is the original horn and both curves overlayed with some smoothing.
The new horns feel like more "dynamic", I have another pair where I plan to smooth out all the edges and paint it black, I think these will stay in until some super nice wooden horns are made for my drivers.
The use of the HF horn does not seem to limit me in any regard, maybe I will use a passive crossover for it. I like the combination a lot - but will not hesitate much to replace it later with the 1.4" driver mentioned above - once there is some extra cash available.
The next step will be a lot of measurements and crossover tuning - the new crossover points will be something like 145/500/5500 Hz and the HF horns will be fixed to the top of the MF horns to have the stack symmetrical, with the upper horns tilted forward.
Definitely an improvement, also in sound, now the treble is just more natural and extended. I will need to do some polar measurements since the pattern in the description sounds too wide to me.
I also tried another ultra cheap horns with a wider pattern than the existing ones - ARB2. The JBL2445J I have are 3dB less sensitive, but the high end is a bit more extended. It is supposed to be a clone of JBL2380
For comparison, here is the original horn and both curves overlayed with some smoothing.
The new horns feel like more "dynamic", I have another pair where I plan to smooth out all the edges and paint it black, I think these will stay in until some super nice wooden horns are made for my drivers.
The use of the HF horn does not seem to limit me in any regard, maybe I will use a passive crossover for it. I like the combination a lot - but will not hesitate much to replace it later with the 1.4" driver mentioned above - once there is some extra cash available.
The next step will be a lot of measurements and crossover tuning - the new crossover points will be something like 145/500/5500 Hz and the HF horns will be fixed to the top of the MF horns to have the stack symmetrical, with the upper horns tilted forward.
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I tried a first order HP on the tweeter and no LP on the MF horn. I can definitely hear the difference in sound, but hard to say if there is a change in quality - there is definitely a "color" change. I plan to use a passive crossover for the tweeter, this was a test on how a single capacitor would work - I would say, it works OK.
By the way, I had the MF horn inverted in phase without knowing it and I had reversed phase on the tweeter by purpose to remove dip at the XO point. Now that was set up properly.
I plan to have a first order series crossover between HF/MF. The XO point is high enough and the 2445 rolls of in a nice manner. My only issue is that the MF is 16 ohms nominal and the tweeter is 8 ohms nominal, while the MF is a bit more sensitive. The next step is to get FR and Z curves and play around in some software before buying the parts.
When changing the crossover points, I removed all the delays that compensated the different placement of the drivers - the maximum delay was around 5 ms, most of it coming from the bass horn. I cannot say I hear any significant change in sound, but for my good feeling, I will adjust that again for the listening position.
As a side note, this system, albeit far from perfect, can sound really scary when there are some effects in the recordings - especially sounds coming from unexpected places. And also revealing some hidden details or unwanted sounds in the recordings. And all that with Spotify Premium as music source via RPI+ Allo Boss or Google Chromecast Audio.
If that was only possible in a smaller package
By the way, I had the MF horn inverted in phase without knowing it and I had reversed phase on the tweeter by purpose to remove dip at the XO point. Now that was set up properly.
I plan to have a first order series crossover between HF/MF. The XO point is high enough and the 2445 rolls of in a nice manner. My only issue is that the MF is 16 ohms nominal and the tweeter is 8 ohms nominal, while the MF is a bit more sensitive. The next step is to get FR and Z curves and play around in some software before buying the parts.
When changing the crossover points, I removed all the delays that compensated the different placement of the drivers - the maximum delay was around 5 ms, most of it coming from the bass horn. I cannot say I hear any significant change in sound, but for my good feeling, I will adjust that again for the listening position.
As a side note, this system, albeit far from perfect, can sound really scary when there are some effects in the recordings - especially sounds coming from unexpected places. And also revealing some hidden details or unwanted sounds in the recordings. And all that with Spotify Premium as music source via RPI+ Allo Boss or Google Chromecast Audio.
If that was only possible in a smaller package
I tried a passive crossover, 2nd order LP and 3rd order HP - described here: JBL2445 to Beyma CP385Nd crossover tuning
Sounds OK, but there are issues with time/phase alignment. I cannot really say I hear the issues. The passive XO will free up two amp and DSP channels for ambience speakers experiments.
Also, I turned the HF/MF section upside down, even with the tweeters pointed at the listening distance ear height, it did not sound right. With the tweeters at ear height, it sounds more like I am used to.
Sounds OK, but there are issues with time/phase alignment. I cannot really say I hear the issues. The passive XO will free up two amp and DSP channels for ambience speakers experiments.
Also, I turned the HF/MF section upside down, even with the tweeters pointed at the listening distance ear height, it did not sound right. With the tweeters at ear height, it sounds more like I am used to.
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Still no time to do proper measurements. The Beymas are now in BC ME-20 horns placed above the midrange horns. I need to align the passively crossed over drivers.
A friend of mine will build a pair of Yuichi horns and 135 Hz horns by John Inlow. Two more bass horns are on the way, I just could not resist
As a side note, the FH-1 clones with Fane 12-250TC in closed boxes make a nice little garden party PA. I only wish I could do something about the beaming, maybe try an acoustic lens made from corrugated cardboard.
A friend of mine will build a pair of Yuichi horns and 135 Hz horns by John Inlow. Two more bass horns are on the way, I just could not resist
As a side note, the FH-1 clones with Fane 12-250TC in closed boxes make a nice little garden party PA. I only wish I could do something about the beaming, maybe try an acoustic lens made from corrugated cardboard.
The bass horns are at home. So now the whole front wall will be basically 4 x 40 Hz bass horns next to each other. The bad thing is that the current midbass horns are too high. If they fit on top of the bass horns I will most probably need to put the mid and HF horns somehow in front of them in a kind of coaxial arrangement (and move the fridge not seen in the picture out of the way
The passive crossover unfortunately does not work too well due to the misaligned drivers. I hope to get some 1" to 2" adapters soon to try two identical horns with both drivers.
The passive crossover unfortunately does not work too well due to the misaligned drivers. I hope to get some 1" to 2" adapters soon to try two identical horns with both drivers.
The Beymas will be mounted to the second pair of JBL2380 clones using a custom made 3D printed adapter which is discussed here: 3D printed 1" to 2" driver adapter - anyone tried before?
I can't help but think that splitting the treble with the two horns is not the way forward as they can never be close enough to each other to avoid uneven response through the room. As the 2380A has a diffraction slot it seems to maintain coverage in the 10-20khz region:
https://www.jblpro.com/pages/pub/components/2380a.pdf
Your system looks very fun though the 15" ported horns are quite something!
https://www.jblpro.com/pages/pub/components/2380a.pdf
Your system looks very fun though the 15" ported horns are quite something!
Uneven response across the room is true now. It is tuned to the listening spot. I tried to EQ the JBL horn flat to 20 kHz, which is possible, but a separate tweeter sounded better. It is an experiment in progress, so I actually plan to get a better midrange driver to cover all up from 500 Hz one day, most probably a 1.4" from BMS.
Yes, they can never be close enough, so I want to at least time align them and match the directivity - I did the time alignment with DSP and I got nice impulse response - and hope o get close to that with a passive crossover.
It is fun for sure, I always liked music played in a horn loaded PA betweez the bands and now I have that at home
Yes, they can never be close enough, so I want to at least time align them and match the directivity - I did the time alignment with DSP and I got nice impulse response - and hope o get close to that with a passive crossover.
It is fun for sure, I always liked music played in a horn loaded PA betweez the bands and now I have that at home
Thanks to GM and his suggestion of using two identical horns and 3D printing, it just sounded right from the first note played. Great, clean, balanced sound over a wider spot. Until I can find a horn/driver combo, that could do the same (not coaxial), I am really happy. As a bonus, it also looks better
The large black horn is the HF - I will most probably soon make a new fixture allowing HF to be positioned on top or between midbass and MF.
Measurements will follow, but now the system is reasonably flat, maybe requiring just a touch of DSP EQ. HF+MF is easily within +- 3 dB window from 500 Hz up, no more notches caused by misalignment.
I wonder if it would make any sense to make a baffle wide as the midbass horn where the HF and MF horns would be flush mounted.
The large black horn is the HF - I will most probably soon make a new fixture allowing HF to be positioned on top or between midbass and MF.
Measurements will follow, but now the system is reasonably flat, maybe requiring just a touch of DSP EQ. HF+MF is easily within +- 3 dB window from 500 Hz up, no more notches caused by misalignment.
I wonder if it would make any sense to make a baffle wide as the midbass horn where the HF and MF horns would be flush mounted.
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