I'm dreaming about a project where BSC could be avoided and 1st order crossovers could be used, to achieve high sensitivity.
1. Two side to side woofers in a bipole configuration, close as possible to the tweeter
Enclosure: ML-TL
-question A, how high can I cut these? How about 200 to 300Hz for 7" midbass units?
2. Two 5" mid-range units in MTM configuration. Being the same impedance as the woofer's and same sensitivity. Enclosures: sealed or dampened quarter wave
-question B. Baffle width gets tricky, isn't it? I need to make it wide enough to avoid baffle step roll off soonest than woofer roll off.
3. Lowest roll-off of the tweeter as possible. I'm aware of the right lobing of MTMs.
What kind of other problems and difficulties should I expect in such project?
1. Two side to side woofers in a bipole configuration, close as possible to the tweeter
Enclosure: ML-TL
-question A, how high can I cut these? How about 200 to 300Hz for 7" midbass units?
2. Two 5" mid-range units in MTM configuration. Being the same impedance as the woofer's and same sensitivity. Enclosures: sealed or dampened quarter wave
-question B. Baffle width gets tricky, isn't it? I need to make it wide enough to avoid baffle step roll off soonest than woofer roll off.
3. Lowest roll-off of the tweeter as possible. I'm aware of the right lobing of MTMs.
What kind of other problems and difficulties should I expect in such project?
Side fired woofers are commonly used as subwoofers and 200-300Hz cross point seems too high. Maybe 80Hz and below would be much better.
I would recommend real subwoofer drivers, at least 8" (10" is better), powered by separate amplifier instead of 7" mid-bass. The smaller drivers won't go that low or if they could, they will have limited sensitivity..
Regards Georgi
I would recommend real subwoofer drivers, at least 8" (10" is better), powered by separate amplifier instead of 7" mid-bass. The smaller drivers won't go that low or if they could, they will have limited sensitivity..
Regards Georgi
Have you considered making the baffle as large as you can?
Going down the road you're suggesting is a long thought process, it might help to see what you've considered and how far you're prepared to go.
Going down the road you're suggesting is a long thought process, it might help to see what you've considered and how far you're prepared to go.
I expect it will have a lot to do with the dispersion of the bass driver. We have successfully used side firing Silver Flute W14 up to 450 Hz.
Of you can get away with it there are huge advantages to a push-push arrangment.
Same sensitivity? If you want to use the transition between mid & woofer you usually want the woofers to be 2-6 dB more sensitive than the mids. XO based on where the BS9-3) sits.
dave
Avoid baffle step ?
Make the woofers cross at the baffle step's f3.
Make sure woofers are 6db louder than mid/tweet.
Lol, like dave said above.
Make the woofers cross at the baffle step's f3.
Make sure woofers are 6db louder than mid/tweet.
Lol, like dave said above.
Thanks folks! Sorry for the late reply, was fighting with severe post-covid symptoms 🙁
Judging by your answers, things get quite complicated.
1. I wish not to make a wide baffle for such project, if possible. Do you mean to front-rear bipole in this case? Sadly the speakers have to be close to a wall, approximately 2 feet.
2. The woofers being so sensitive? So I must find a less sensitive tweeter/midrange. The woofers are 87-88 db/W/m
Judging by your answers, things get quite complicated.
1. I wish not to make a wide baffle for such project, if possible. Do you mean to front-rear bipole in this case? Sadly the speakers have to be close to a wall, approximately 2 feet.
2. The woofers being so sensitive? So I must find a less sensitive tweeter/midrange. The woofers are 87-88 db/W/m
You could side mount the woofers and load them push-push. It makes them a WWMTM thou, unles you go WWMTMWW
dave
dave
You're ok with the baffle step itself happening, but want simpler electrical dealings.
Have you considered the 2.5 way? A second woofer is used to cover the region in question and fill the response, that is its only job. It typically uses a first order crossover so it continues to fit in with the other woofer and tweeter.
Have you considered the 2.5 way? A second woofer is used to cover the region in question and fill the response, that is its only job. It typically uses a first order crossover so it continues to fit in with the other woofer and tweeter.
It doesn't make sense to me if I put it on the back for a bipole. That way, the need for BSC is not anymore and there will be two bass reinforcement vs only one midrange in the front. We're talking about a 2 way here. The back speaker won't keep up in the midrange like the front one, will it?
Think of it this way, there will be the primary issue, the baffle step proper. At low frequencies it doesn't make a difference whether it is on the front or back.
Then there are likely to be smaller secondary issues. The subtleties of how the middle frequencies diffract around the cabinet etc. Things you should hopefully be able to measure and adjust.
Now if you were to put the woofer on the back, in theory it wants the same crossover frequency as a 2.5 way mounted on the front. Any higher and you have unnecessary midrange directing backward, and any lower and you don't fully support all of the baffle step radiation.
It might be slightly different in practice as suggested above.
Then there are likely to be smaller secondary issues. The subtleties of how the middle frequencies diffract around the cabinet etc. Things you should hopefully be able to measure and adjust.
Now if you were to put the woofer on the back, in theory it wants the same crossover frequency as a 2.5 way mounted on the front. Any higher and you have unnecessary midrange directing backward, and any lower and you don't fully support all of the baffle step radiation.
It might be slightly different in practice as suggested above.
I just rescued these old units from the Evil Step Daughters shed. The small sealed box on the bottom held a 10inch LF woofer. Other drivers were 8's and 4's. Lots of tweaking by ear but the mids were never good enough. They are now a project looking for some good cheapish 4" drivers to replace the POS that I was experimenting with. Going sealed really helped a lot even with simple first order on the 10" and the 8's. Mids needed 3rd order tho and I'm hoping to reuse the XO tho to save some dollars. Anyway the sealed bass unit was my solution. 4R woofer with a 5.6mH coil in front of it. 30 litre box
~250mm baffle
~250mm baffle
