The spreadsheet I use was written by Thorsten Loesch, based on a compilation of others work (White Allison, Steele).
It does not allow print a graph, but with printscreen I can copy it.
I have measured the parameters of the speakers, and the 2A9 have too low a Q for my purpose, so in time I will replace them and sell them.
But they do give a marvelous depth to the sound. Best should be to find someone who can make a new spider with a high Q.
See my current simulation with 2A3 on top. It is interesting that the moment I turn around the speakers, the 2A9 at the bottom, the two outputs coincide!
I included the spreadsheet.
It is a simple version (I expect it calculates from a point source on the baffle), on the web there is a sophisticated version (for sale) that allows sort of depicting many small speakers to get a more realistic output. I do not have that version
I have used a boost in the preamp but I discarded it as too artificial.
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Just came across this thread. I want to share my experience.
I use a German 8" Greatz field coil speaker on an open baffle. I have a simple Foster Horn tweeter crossed in at above 10khz.
This is all on a baffle of just over 16" wide.
Here is the thing I tried to make an acceptably small baffle for my (wife) livingroom. I got some nice 10" bass drivers from an old B&O system. Instead of trying to brute force the bass I put them into a smallish aperiodic box (leaky vent box), this means that these relatively small bass drivers put out very clean and relatively deep bass without to much effort and without a massively wide baffle.
Aperiodic boxes are a sensible compromise solution for a OB coupled to a nice medium sized field coil or alnico fullrange driver. The German Greatz drivers sound surprisingly good and can be had for less than €200.00 a pair. Mine had an anular ring which needed damping to calm down a nazal honk and I added a simple hollow phase plug to the naked pole piece.
Overall for a set of speakers which which date back to the seventies at the earliest they sound amazingly detailed and modern.
Shoog
I use a German 8" Greatz field coil speaker on an open baffle. I have a simple Foster Horn tweeter crossed in at above 10khz.
This is all on a baffle of just over 16" wide.
Here is the thing I tried to make an acceptably small baffle for my (wife) livingroom. I got some nice 10" bass drivers from an old B&O system. Instead of trying to brute force the bass I put them into a smallish aperiodic box (leaky vent box), this means that these relatively small bass drivers put out very clean and relatively deep bass without to much effort and without a massively wide baffle.
Aperiodic boxes are a sensible compromise solution for a OB coupled to a nice medium sized field coil or alnico fullrange driver. The German Greatz drivers sound surprisingly good and can be had for less than €200.00 a pair. Mine had an anular ring which needed damping to calm down a nazal honk and I added a simple hollow phase plug to the naked pole piece.
Overall for a set of speakers which which date back to the seventies at the earliest they sound amazingly detailed and modern.
Shoog
I had dual sealed 8" subs under my fullrange drivers, and I thought that was quite nice. It is indeed the easy way to get some bass in a small package.
I've since switched the sealed 8" for a couple of 15" in OB, and strangely enough, the wife was ok with the change.
What I gained is bass even at low volume, which I didn't have before with the dual sealed 8 inchers.
But yes, for someone who is space constrained, smaller sealed or vented boxes will do fine for the low end.
It's always a balance between what we want and what we can do.
I've since switched the sealed 8" for a couple of 15" in OB, and strangely enough, the wife was ok with the change.
What I gained is bass even at low volume, which I didn't have before with the dual sealed 8 inchers.
But yes, for someone who is space constrained, smaller sealed or vented boxes will do fine for the low end.
It's always a balance between what we want and what we can do.
Aperiodic behave very like Transmission Lines if set up correctly. They will tend to have a slightly higher cutoff point than a typical TL. They are a very different beast to any form of reflex ported designs.
The issue I see with sealed box subs is that they need significant power to drive and powerful magnets to overcome the airspring without heavy distortion. This makes them a very poor match to the typically 100db/w field coil drivers they are been partnered with. Aperiodics present little back load to the sub so they are easy to drive.
Shoog
The issue I see with sealed box subs is that they need significant power to drive and powerful magnets to overcome the airspring without heavy distortion. This makes them a very poor match to the typically 100db/w field coil drivers they are been partnered with. Aperiodics present little back load to the sub so they are easy to drive.
Shoog
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