I have some 4592's (mid/high coax) and may be using the passive crossover for these. Not sure yet. I've seen the stock crossover and components don't seem to be that great.
So I'm wondering if anyone has built a good crossover for the 4592. I was going to look at Xsim to see if that could help me build the XO.
Suggestions would be appreciated.
So I'm wondering if anyone has built a good crossover for the 4592. I was going to look at Xsim to see if that could help me build the XO.
Suggestions would be appreciated.
Hi Johnnyjo,
Nice looking drivers!
I always promote XSim, but to make any Xover simulator work correctly you need impedance, frequency and distance. If you can use a pre-designed crossover / horn you would find a much easier time. If you'd like an example of what a complete simulation looks like, find the LM-1 thread and look at the Xsim files near the end.
Another alternative of course is to keep the crossover but upgrade the caps.
Post a pic of what you have.
Best,
Erik
Nice looking drivers!
I always promote XSim, but to make any Xover simulator work correctly you need impedance, frequency and distance. If you can use a pre-designed crossover / horn you would find a much easier time. If you'd like an example of what a complete simulation looks like, find the LM-1 thread and look at the Xsim files near the end.
Another alternative of course is to keep the crossover but upgrade the caps.
Post a pic of what you have. Best,
Erik
Title Fixed
Hi Johnnyo,
You need the frequency response of the individual drivers in their cabinet/location before you can determine a crossover or XO frequency. Looking at the BMS website they claim the drivers share the same distance. Not sure if that's true, but here's a blog on how and why you measure distances.
Best,
Erik
You need the frequency response of the individual drivers in their cabinet/location before you can determine a crossover or XO frequency. Looking at the BMS website they claim the drivers share the same distance. Not sure if that's true, but here's a blog on how and why you measure distances.
Best,
Erik
The horn/waveguide used has a major effect on the passive crossover circuit. Constant directivity waveguides like the SEOS24 require significant high frequency boost for a flat in-room response. The shape of the front baffle, and the location of the horn on the baffle also effects the crossover circuit. example - Locating the horn/waveguide at the top edge of the cabinet can extend the "narrow" directivity control from the horn to a lower frequency than if there are several inches of baffle wood above the horn/waveguide extending the 180-degree baffle forward projection.
Attached one example passive crossover for the BMS 4594Nd on a SEOS24 waveguide. This circuit topology is used in a few posted DIY designs. A first order 6db circuit using one high quality capacitor is common for the tweeter coil for low phase shift.
Measure twice, Spend once, Enjoy many times!
Attached one example passive crossover for the BMS 4594Nd on a SEOS24 waveguide. This circuit topology is used in a few posted DIY designs. A first order 6db circuit using one high quality capacitor is common for the tweeter coil for low phase shift.
Measure twice, Spend once, Enjoy many times!
Attachments
I'm using an RCF HF950 Horn. The cutoff freq on that horn is 400Hz. I need to play the BMS 4594 coaxial low since I'm using an MTM configuration. So I was calculating around 550Hz.
I thought I could use the stock crossover. However, I'm after the best sound out of these because the coax driver is expensive. So might as well get the best sound I can get.
From what I gather the stock xo is shown below. I don't know the value of the inductor yet. If I do use the stock xo and just upgrade the caps, the 4.4uF is hard to find in quality caps.
I thought I could use the stock crossover. However, I'm after the best sound out of these because the coax driver is expensive. So might as well get the best sound I can get.
From what I gather the stock xo is shown below. I don't know the value of the inductor yet. If I do use the stock xo and just upgrade the caps, the 4.4uF is hard to find in quality caps.
An externally hosted image should be here but it was not working when we last tested it.
2 x 2.2uF in parallel will give you 4.4uF then you only need to buy one value of capacitor.
If you want to improve much over the stock crossover then active would be the way to go. An active passive hybrid could also do well with only 2 amp channels per side.
Use a 2 channel active crossover to split the signal and process separately then use passive components for one of the crossover points.
e.g active for the two drivers in the coax and then then passive for the woofer to lower coax crossover. Design a passive crossover for the woofer to coax and then use the active to replace the BMS passive crossover.
Depending on the response of the drivers it may be better to use the active split in a different way, but the benefit is that you can apply all the notches and tweaks you want to the signal and avoid having to have lots of passive components which when high power and quality is needed can be very expensive.
Two stereo amps can the be used to drive the system.
e.g active for the two drivers in the coax and then then passive for the woofer to lower coax crossover. Design a passive crossover for the woofer to coax and then use the active to replace the BMS passive crossover.
Depending on the response of the drivers it may be better to use the active split in a different way, but the benefit is that you can apply all the notches and tweaks you want to the signal and avoid having to have lots of passive components which when high power and quality is needed can be very expensive.
Two stereo amps can the be used to drive the system.
FYI, as long as you don't listen very loud, you could even get away with no crossover between the 4594's mid and tweeter. Their crossover is mainly for protecting the HF driver. If you truly need flat response at the crossover frequency, you will need some form of DSP. This is coming from my experience with the 4594 and SEOS 24.
The crossover point on the BMS boards is 6.3Khz and the components will be different for the change in impedance, the 16Ohm will need less padding to match levels with the woofers.
This was from the US distributor in another thread
With only 2 capacitors and an inductor it would seem to be 1st order highpass and second order lowpass
At 16 Ohms 1.58uF will give you a 6.3KHz First Order Highpass
1.12uF and 0.57mH will give a 6.3KHz second order butterworth lowpass
Standard values should get you close
Maybe send an email to BMS support to ask for more information that might give you the values. They have responded to questions via email quite quickly.
contact at bmsspeakers.com
It would also seem that leaving the passive on the coax and using the active split between the woofer and coax would probably be the better way to go. Easy enough to EQ the coax as a whole to fix the response you get in the horn you have.
I'm just about to try the BMS 4594nd drivers with my Azura 340 horns (LeCleach) and I've been looking for crossovers.
Came across a good post here from @LineSource that mentioned:
"Constant directivity waveguides like the SEOS24 require significant high frequency boost for a flat in-room response".
Although my LeCleach horns are a different profile I have found that even though the Yamaha 6681b driver I'm now using is meant to have a flat response it falls away as the frequency increases.
As I want this system to be passive, the crossover shown in post 9 might be what I'm after to help compensate for the horn HF roll-off.
Does anyone have any comments or advise before I start ordering these parts?
Been looking too much and now its time to start building!!!
Cheers
Came across a good post here from @LineSource that mentioned:
"Constant directivity waveguides like the SEOS24 require significant high frequency boost for a flat in-room response".
Although my LeCleach horns are a different profile I have found that even though the Yamaha 6681b driver I'm now using is meant to have a flat response it falls away as the frequency increases.
As I want this system to be passive, the crossover shown in post 9 might be what I'm after to help compensate for the horn HF roll-off.
Does anyone have any comments or advise before I start ordering these parts?
Been looking too much and now its time to start building!!!
Cheers
sorry to drag you back with an old post!
What happened with your build? Im looking to get these drivers with a similar horn (while Im waiting for the woofers to arrive in 3 weeks!).
Thanks
G'day mate, I've still got those driver's..... In a box somewhere! They worked really well but I found the Yamaha 6681B drivers were just a smig smoother. Being coaxial they were easy to mount in the mid horns, also didn't take much xover as they have quite a step natural roll off between driver elements.
Do you want a pair? Make an offer....
Do you want a pair? Make an offer....
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