I put a pair of Alpair 10.2 in a repurposed pair of cabs from an old pair of B&W DM100 speakers.
They do make pretty decent bass, but the mids ended up 'shouty' sounding. There was too much midrange; they sounded far too 'forward' and 'aggressive'. Not horrible, but noticeably off.
I have a collection of 30-some odd years' worth of speaker chokes of various values, and a decent selection of 5W wirewound resistors. I read up on baffle step compensation networks, calculated a ballpark set of values, and wired them in.
After experimenting for a few days, I wound up with a 3.3mH choke and 10R resistor in parallel, placed in series with the + lead from the amplifier to speaker + binding post.
The - lead from the amplifier is connecting directly to the speaker's - binding post.
I used two pairs of speakers I have as references, and tried to get the Alpairs to sound as close to those speakers as possible. (The other two speakers are JBL Studio 530 and Snell E/III.) I got close enough to where I'm now happy using the Alpair 10,2 speakers as my nearfield PC speakers.
My question is, do my BSC values sound in the ballpark, or am I making a mess of things?
They do make pretty decent bass, but the mids ended up 'shouty' sounding. There was too much midrange; they sounded far too 'forward' and 'aggressive'. Not horrible, but noticeably off.
I have a collection of 30-some odd years' worth of speaker chokes of various values, and a decent selection of 5W wirewound resistors. I read up on baffle step compensation networks, calculated a ballpark set of values, and wired them in.
After experimenting for a few days, I wound up with a 3.3mH choke and 10R resistor in parallel, placed in series with the + lead from the amplifier to speaker + binding post.
The - lead from the amplifier is connecting directly to the speaker's - binding post.
I used two pairs of speakers I have as references, and tried to get the Alpairs to sound as close to those speakers as possible. (The other two speakers are JBL Studio 530 and Snell E/III.) I got close enough to where I'm now happy using the Alpair 10,2 speakers as my nearfield PC speakers.
My question is, do my BSC values sound in the ballpark, or am I making a mess of things?
Dimensions (H x W x D): 370 x 220 x 210 mm.
If we assume 15mm material (what is it in reality), about 12 litres. Similar in size to the smaller Mar-Ken10.2. We found no need for BSC.
From your description you may need some midrange suppression.
Did you relieve the back of the driver cutout. What amplifier are you using.
dave
If we assume 15mm material (what is it in reality), about 12 litres. Similar in size to the smaller Mar-Ken10.2. We found no need for BSC.
From your description you may need some midrange suppression.
Did you relieve the back of the driver cutout. What amplifier are you using.
dave
Hi Dave
I did relieve the back of the driver cutout some. Not as much as recommended, as I didn't want to make a mess of it, and I'm not a competent woodworker.
Can you describe the sound that results from inadequate relief of the back of the driver cutout? A 'honky' or 'squawky' resonance, perhaps?
The amplifier for testing purposes was a Behringer A800. It's a bit of a beast -- a class D amp that can make 140W into 8 ohms. It has a low Zout.
The amplifier I'm using from the PC is a cheapie TPA3116 with "Breeze Audio" on its front panel. I think it makes about 20W into 8 ohms. That amp probably has a high-ish Zout, which I suppose helps the bass come up a little.
I did relieve the back of the driver cutout some. Not as much as recommended, as I didn't want to make a mess of it, and I'm not a competent woodworker.
Can you describe the sound that results from inadequate relief of the back of the driver cutout? A 'honky' or 'squawky' resonance, perhaps?
The amplifier for testing purposes was a Behringer A800. It's a bit of a beast -- a class D amp that can make 140W into 8 ohms. It has a low Zout.
The amplifier I'm using from the PC is a cheapie TPA3116 with "Breeze Audio" on its front panel. I think it makes about 20W into 8 ohms. That amp probably has a high-ish Zout, which I suppose helps the bass come up a little.
Often the case.
Both the class D amps will have low Rout, a higher RRout amplifier may have teh same effect as teh BSC>
dave
The boxes are sealed right? Guessing that's not helping the brightness in the mids. Are the 10.2s broken in?
jeff
jeff
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It's a start. Perhaps tuned a little low, hard to say without measuring. Your impedance rise toward higher frequencies may come through as a treble boost.
The boxes are ported. I started out with them sealed, which does produce enough bass to be listenable, keeping in mind that the cabs are in the mini-monitor size class. The ports added some oomph. It's a semi-aperiodic kind of thing, by accident. I have two 2" tubular ports in each cab. One of them is stuffed tightly with poly wadding. The open port is 2 inches D x 6 inches L.
The 10.2s are downright old. Well broken in, many hours of use.
Perhaps I need to open them back up and put more relief on the back of the driver cutouts.
But if the BSC network values sound reasonable then I think I'm happy enough with them to use them for a while as is. I'll probably get the itch to experiment some more in a few months.
The 10.2s are downright old. Well broken in, many hours of use.
Perhaps I need to open them back up and put more relief on the back of the driver cutouts.
But if the BSC network values sound reasonable then I think I'm happy enough with them to use them for a while as is. I'll probably get the itch to experiment some more in a few months.
BTW, when I had them connected to the big system, powered by the A800 amp, they sounded surprisingly good. I like the lack of crossover in the midrange. Voices have a coherence I don't get from 2-ways. I can see why so many people really like these drivers.
If it sounds ok, then just leave it in. Yeah, the old A10.2's were pretty decent, so not surprised you like them.
jeff
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