Just thought I'd add a bit of modelling I did on this design.
So, took the SB driver data, traced it and put it into Boxsim 2.0. Modeled as close as I could the box and the driver positions. SB23's in 25litres sealed each with fairly heavy stuffing, SB15 in Sealed 4litres heavily stuffed.
As I will probably be using a nanodigi I then put in a very basic LR2 crossover at 200hz and 2.8khz (matched on parallel bass and tweeters, mid out of phase), all drivers at 0 gain and no delay added. And you can see the response below, can it be really this good ! (note I did model the published crossover passively and this is still very good as well)
Relatively flat with a littler lower mid/upper bass hump, phase looks very good at crossover frequencies and there are some very good nulls when the mid polarity is reversed. Probably would add a notch at 700hz, 2500hz and 8500hz to flatten it out but that would be final tweaks.
All comments welcome.
So, took the SB driver data, traced it and put it into Boxsim 2.0. Modeled as close as I could the box and the driver positions. SB23's in 25litres sealed each with fairly heavy stuffing, SB15 in Sealed 4litres heavily stuffed.
As I will probably be using a nanodigi I then put in a very basic LR2 crossover at 200hz and 2.8khz (matched on parallel bass and tweeters, mid out of phase), all drivers at 0 gain and no delay added. And you can see the response below, can it be really this good ! (note I did model the published crossover passively and this is still very good as well)
Relatively flat with a littler lower mid/upper bass hump, phase looks very good at crossover frequencies and there are some very good nulls when the mid polarity is reversed. Probably would add a notch at 700hz, 2500hz and 8500hz to flatten it out but that would be final tweaks.
All comments welcome.
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To be honest, if/when I ever get to build these then as it is +/-1db between 400hz and 15khz around and average of 89db with such a simple crossover it’s probably not worth the effort to do the notches.
But as this is a very basic crossover it looks so good as a starting point, moving the upper crossover point a few hz Down for the tweeter this may solve the 2500hz dip and the same for the lower dip as well, hopefully this will not mess up the phase. May have a play later.
But as this is a very basic crossover it looks so good as a starting point, moving the upper crossover point a few hz Down for the tweeter this may solve the 2500hz dip and the same for the lower dip as well, hopefully this will not mess up the phase. May have a play later.
You will hear the output from the mid 5k. I really suggest changing crossover, the notch won't work because it only works for narrow peaks not for spread over 2 octaves. Additional coil or coil and capacitor with resistor should work.
It seems there’s a vacuum when it comes to info about these speakers. It looks like there may be info on them on a Facebook page (I don’t have FB), but there’s basically no talk about them on forums and no one (ie Meniscus) offers a kit version.
Am I just horrible at using Google?
Am I just horrible at using Google?
I, too, don't like to see any resonances. So I aim to strike out resonances down to below the noise floor. So in my room, if I'm playing at 85dB (C) then I want resonances to be below 45dB for lower. So I think "down 40dB" is safe. But is 30? or 20dB? Or do I need 50dB?
I don't know if there's any research that answers that, at least not that I've seen.
And the question is whether the resonance is sufficiently suppressed, on their own, or whether they are masked by other driver eg. tweeter, or effects of the room.
Like if I'm playing at 100dB I can hardly hear anything else, and there's a good question whether something down 20dB is even audible, particularly when it's masked by the tweeter.
This is a different question to whether Jeff can make a good sounding speaker (he can), or whether he didn't hear the resonance, or whether he thought the resonance but minor but didn't think it was worth spending more crossover parts to suppress it more.
I don't know if there's any research that answers that, at least not that I've seen.
And the question is whether the resonance is sufficiently suppressed, on their own, or whether they are masked by other driver eg. tweeter, or effects of the room.
Like if I'm playing at 100dB I can hardly hear anything else, and there's a good question whether something down 20dB is even audible, particularly when it's masked by the tweeter.
This is a different question to whether Jeff can make a good sounding speaker (he can), or whether he didn't hear the resonance, or whether he thought the resonance but minor but didn't think it was worth spending more crossover parts to suppress it more.
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Most of my listening is at 75-78-80dB at listening spot.
No particular genre of music. I'll listen anything from scandinavian jazz, balkan ethno music, swing, funk, acoustic, electronic... Anything from Rammstein to Arvo Pärt - if i like it, i listen. For a few months i'll listen one genre (or even one band sometimes), then i'll switch to other genre when i feel the hunger for different type music.
I am more inclined to listen a good recordings which is almost always with movie soundtracks, so for a few years it is more often on the repertoire. I guess their movie budgets are enormous so they can afford good composers and studio work. We'll see if that practice continues when this covid **** ends.
This was discussed where Jef Bagsby was active, on his FB page "DIY Loudspeaker Project Pad". He was not so active on this forum or any others anymore since he had that page (which is very popular and active, even after his death). And he did sell his kits always trough Meniscus, so ...
This is a big speaker …would it be possible to replace the woofer pair with a pair of SB17cac …while doing the wish list maybe a pair of Viawave SRT-7 as tweeters!