Hi all,
I'm not really up on speaker design and crossovers, but I've inherited some fairly hefty 25mm MDF cab 3-way speakers of unknown origin. I've been told they were originally 4-way, as there was a hole in the back of the mid enclosure (now sealed) which originally house a small ribbon tweeter (which is weird in itself).
External dimensions are: 1150mm high, 330mm deep, 220mm wide with the mid enclosure taking up the top 180mm.
The Mid driver is in a sealed box at the top front, HF driver is in the bottom half of the cab mounted just below the Mid driver in the same box as the 2 parallel LF drivers which are fitted rear mounted at the bottom of the enclosure.
The crossovers are DIY point-to-point wired on MDF boards, the LF separate, but both wired to the terminals. I don't have any component values (including drivers) other than the caps and resistors.
I have absolutely no details on the drivers other than the tweeter is silk dome, them mid is 4" kevlar, and the 2 bass drivers are 6" (unknown material).
Sound wise, they are not the worst sounding speakers I have ever heard. The mid's/hf's are pretty tight, but the bass is a little flabby (all subjective mind you).
Any thoughts on the crossovers (apart from the obvious mistake at C2 which should be in parallel with R1)?
😕
I'm not really up on speaker design and crossovers, but I've inherited some fairly hefty 25mm MDF cab 3-way speakers of unknown origin. I've been told they were originally 4-way, as there was a hole in the back of the mid enclosure (now sealed) which originally house a small ribbon tweeter (which is weird in itself).
External dimensions are: 1150mm high, 330mm deep, 220mm wide with the mid enclosure taking up the top 180mm.
The Mid driver is in a sealed box at the top front, HF driver is in the bottom half of the cab mounted just below the Mid driver in the same box as the 2 parallel LF drivers which are fitted rear mounted at the bottom of the enclosure.
The crossovers are DIY point-to-point wired on MDF boards, the LF separate, but both wired to the terminals. I don't have any component values (including drivers) other than the caps and resistors.
I have absolutely no details on the drivers other than the tweeter is silk dome, them mid is 4" kevlar, and the 2 bass drivers are 6" (unknown material).
Sound wise, they are not the worst sounding speakers I have ever heard. The mid's/hf's are pretty tight, but the bass is a little flabby (all subjective mind you).
Any thoughts on the crossovers (apart from the obvious mistake at C2 which should be in parallel with R1)?
😕
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You can tighten the bass if you block the vent and put a good amount of staffing inside the enclosure.
Topology of the crossover is OK.
Woofers on the back of the enclosure is an odd design, but not unheard of.
Topology of the crossover is OK.
Woofers on the back of the enclosure is an odd design, but not unheard of.
Check the values of the caps. C5 & C4 most likely culprits (if not tired woofer spiders).
I'm assuming it's not on purpose.
I'm assuming it's not on purpose.
There are some foam panels in the bottom of the enclosure. but I'll get some extra flocking and see if that improves things. I'll also try blocking the vent with some high density foam and see if that makes a difference.
C4 is a polypropylene 33uF/100v (Bennic), and C5 is a bipolar electrolytic 100uF/100v (Mundorf E-Cap Audio Raw). The Mundorf caps look brand new.
I haven't got a Capacitance meter, but they appear normal (infinite resistance after a short period) when checked with a multi-meter.
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it was once quite popular to add a rear facing tweeter to balance the power response, some is still using it
I think reward facing woofers is your problem. The crossover to the midrange is ~500Hz plus, so all the upper bass / lower mids are reflected and time delayed relative to the midrange above 500Hz, which is a really bad idea. With a front facing port mid-bass from the rear of the cones leaking out through the port may well dominate over the radiation off the front of the drivers as well. I don't even like the sound of rear or sideways bass drivers with a crossover as low as 100Hz because they do not integrate properly IMO.
I can't see fiddling with the crossover as a means to fix this. I would turn the box around and mount the mid and tweeter on the same baffle as the bass drivers, and block up the old holes.
I can't see fiddling with the crossover as a means to fix this. I would turn the box around and mount the mid and tweeter on the same baffle as the bass drivers, and block up the old holes.
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