You might find this useful. See enclosed crossover for the B2500.1 and ATC mid
Note: The ATC is VERY difficult to integrate with the bass driver and equalise with a passive crossover.
FYI- Adjust the ATC level using R2. R1 is required to help equalisation and not to be used for level adjsutment. Capacitor C1 is critical so experiment with different values to get the best sound. R3 is used to equalise the response peak on the ATC. 8.2ohms works best on my setup.
If you can get it right then it's well worth the effort
Note: The ATC is VERY difficult to integrate with the bass driver and equalise with a passive crossover.
FYI- Adjust the ATC level using R2. R1 is required to help equalisation and not to be used for level adjsutment. Capacitor C1 is critical so experiment with different values to get the best sound. R3 is used to equalise the response peak on the ATC. 8.2ohms works best on my setup.
If you can get it right then it's well worth the effort
Attachments
I have used both the S and standard version of the ATC. The xover works for either. Adjust R2 to get the correct level to match the bass driver.
I have also used many different Volt drivers over the years including the
B250, RV3143, BM220 and the B2500.1. The B2500.1 for me sounds by far the
best. I know it doesn't model well at 75l but I have tried the driver with various size enclosures and it sound best at 70 or 75l tuned to 30Hz - 32Hz. The driver gives a very tight controlled bass with no boom. Ideal for the ATC mid. The only problem with this driver is it is very sensitive to any air leaks in the enclosure and you need to 2/3 fill the enclosure with wadding. Careful adjustment of the port tunning is required to get the best sound. Even 1Hz
deviation is critical.
I have also used many different Volt drivers over the years including the
B250, RV3143, BM220 and the B2500.1. The B2500.1 for me sounds by far the
best. I know it doesn't model well at 75l but I have tried the driver with various size enclosures and it sound best at 70 or 75l tuned to 30Hz - 32Hz. The driver gives a very tight controlled bass with no boom. Ideal for the ATC mid. The only problem with this driver is it is very sensitive to any air leaks in the enclosure and you need to 2/3 fill the enclosure with wadding. Careful adjustment of the port tunning is required to get the best sound. Even 1Hz
deviation is critical.
Thanks again spd. Interesting that you rate the B2500.1 over the B250.8 that I have are they close would you say? I was going to go with the 2500.1's myself but my cab is already tuned to 26Hz and the 250.8 looked like it would cope with that better. I am going to proceed with your design as you have obviously developed yours over time and so is a good place to start for mine. I have ordered the components for the xover so will let you know how I get on. One last question. All my drive units are brand new, would you reccomend running them in before fine tuning? I am guessing Yes.
Regards, Ed
Regards, Ed
The B250 will give good results with the ATC, giving a fairly punchy/warm bass sound. You will need to re-tune your cabinet to around 32Hz in 80l for
the B250. For the B2500 reduce the cabinet volume to 70l and tune to 30Hz.
Use bricks to reduce the internal volume of the cab. Make sure you put a few layers of wadding behind the bass driver to absorb rear sound from the
driver. The B250 will need around 40% wadding fill the B2500 around 60%.
You can experiment with wadding volume and placement to get the best sound. The B250 is far less critical for wadding placement and port tunning
frequency. The B2500 is very fusy and takes lots of experimenting with wadding and tuning frequency to get the best out of it.
Not sure about running in the drivers - I think the difference is small compared to crossover setup and port tunning etc. By the time you get this right the drivers will be run in. Do you have any sound measuring equipment?
the B250. For the B2500 reduce the cabinet volume to 70l and tune to 30Hz.
Use bricks to reduce the internal volume of the cab. Make sure you put a few layers of wadding behind the bass driver to absorb rear sound from the
driver. The B250 will need around 40% wadding fill the B2500 around 60%.
You can experiment with wadding volume and placement to get the best sound. The B250 is far less critical for wadding placement and port tunning
frequency. The B2500 is very fusy and takes lots of experimenting with wadding and tuning frequency to get the best out of it.
Not sure about running in the drivers - I think the difference is small compared to crossover setup and port tunning etc. By the time you get this right the drivers will be run in. Do you have any sound measuring equipment?
Thanks again for the help. The cabs have foam in places at the moment and I was going to damp the boxes with some bitumin sheets to deaden them and I will go for a 40% fill as you suggest. I don't have any sound measuring equipment. I guess with a good quality soundcard and mic you could use a PC?
Regards
Ed
Regards
Ed
Ed, not sure if can change your order but if you talk very nice to ATC they will sell direct. Bought mine from them direct and saved 100's.
Good luck with the project it will a good challange but well worth it.
Thanks for that, very handy to know. Project is on hold for a bit as I now have to find a new job.
design with atc sm75 16 ohm standard version
Hello Spd.
I have owned atc sm75 16 ohm standard version (non s version) plus b2500.1 and T25CF. The project is pending quite sometime and i need to design an enclosure with 70L tuned to 30hz as your recommendation. Can i use your crossover schematic with little modification to adjust/ equalize the impedance and spl response (ie. adjusting R2 and R3)? Do you have other crossover design for sm75 16 ohm standard version?
Thanks and appreciate for your advise.
Regards
daniel.
Hello Spd.
I have owned atc sm75 16 ohm standard version (non s version) plus b2500.1 and T25CF. The project is pending quite sometime and i need to design an enclosure with 70L tuned to 30hz as your recommendation. Can i use your crossover schematic with little modification to adjust/ equalize the impedance and spl response (ie. adjusting R2 and R3)? Do you have other crossover design for sm75 16 ohm standard version?
Thanks and appreciate for your advise.
Regards
daniel.
Hi - I have not tried the 16ohm version but I would think that the crossover
would need to be re-designed. ie, Component values would need to be changed. You will need to measure the response from the ATC to work out
the new values. Doing it only by ear is not simple because the ATC mid has a non-linear response so it's easy to get confused.
I will dig out some response plots so you can see what to aim at - if that helps. The ultimate end result will be amazing with this set of drivers. If you can get the xover right.
would need to be re-designed. ie, Component values would need to be changed. You will need to measure the response from the ATC to work out
the new values. Doing it only by ear is not simple because the ATC mid has a non-linear response so it's easy to get confused.
I will dig out some response plots so you can see what to aim at - if that helps. The ultimate end result will be amazing with this set of drivers. If you can get the xover right.
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