Heh, it's interesting how hard things get and shows quite obviously why high sensitivity loudspeakers are a rare thing in consumer audio. Use a 93dB mid and you need a 97+ dB bass driver to keep up once bafflestep is dialed in.
One thing to perhaps consider is mounting the bass driver very close to the floor, this effectively adds the floor in as the baffle and significantly reduces the effects of bafflestep, thus allowing you to use a 93-94dB bass driver with the 93dB mid. I tried measuring this outside and the floor mounted driver didn't show any baffle step losses at all.
You do obviously have to keep the xover point to the mid low enough so that comb filtering/lobing issues don't occur, but I can't see this being too much of a problem @ 500Hz, especially if this isn't intended for any overly critical listening.
One thing to perhaps consider is mounting the bass driver very close to the floor, this effectively adds the floor in as the baffle and significantly reduces the effects of bafflestep, thus allowing you to use a 93-94dB bass driver with the 93dB mid. I tried measuring this outside and the floor mounted driver didn't show any baffle step losses at all.
You do obviously have to keep the xover point to the mid low enough so that comb filtering/lobing issues don't occur, but I can't see this being too much of a problem @ 500Hz, especially if this isn't intended for any overly critical listening.
That's a good point, shame I can't use the floor.
I have to build these to "fly" from the roof but it isn't a critical listening area.
Salvaging drivers from old boxes is an interesting exercise. Some of those early Japanese speakers were very efficient, comes from only having 5 or 6 watts to drive them I guess.
I build the new mock-up later today, I really need to rebuild my tower computer too, I cannot plug a mike into this old laptop easily.
I have to build these to "fly" from the roof but it isn't a critical listening area.
Salvaging drivers from old boxes is an interesting exercise. Some of those early Japanese speakers were very efficient, comes from only having 5 or 6 watts to drive them I guess.
I build the new mock-up later today, I really need to rebuild my tower computer too, I cannot plug a mike into this old laptop easily.
One other factor to consider in the build is using what parts are " in the box " so to speak and trying to stay with-in standard values.
I just happen to have a pair of 5.8mH P-cored coils that I want to use in the mid XO, so I will be doing a juggling act with other components, like adding a few turns of wire to the other laminate coil to increase the inductance from its value of 5.6.
If I have to make a choice I try and use the higher resistance coils in the return to common and save the lower DCR stuff for the signal path in to the woofer and I can't unwind the dipped P-cores with out doing damage to them.
I just happen to have a pair of 5.8mH P-cored coils that I want to use in the mid XO, so I will be doing a juggling act with other components, like adding a few turns of wire to the other laminate coil to increase the inductance from its value of 5.6.
If I have to make a choice I try and use the higher resistance coils in the return to common and save the lower DCR stuff for the signal path in to the woofer and I can't unwind the dipped P-cores with out doing damage to them.
Been a while on this one, My mate has been using my big Tandy dual 8s as his garage set-up until now. He was just given a set of "White Van" 3 way speakers and wants me to help fix them up. This mid will fit in an existing hole. BTW those figures from Jaycars graph were of this driver in its plastic cup so the FS really is quite low if its Fb is 350Hz. I'm still looking in the parts box.
He is mounting these on a back wall about 1500 off the floor; I'm considering putting in an extra woofer firing down ( Garage speakers and not real Hi-Fi ) and just tilting the whole box a bit. Workshop on speakers over the week-end so I'll see what develops, Mates budget is as limited as mine at the moment, coils for the woofer are going to be the limiting factor as he owes me $70- for the mids and his budget is only $100-
New computer and ALL of my old data and projects have been lost.
He is mounting these on a back wall about 1500 off the floor; I'm considering putting in an extra woofer firing down ( Garage speakers and not real Hi-Fi ) and just tilting the whole box a bit. Workshop on speakers over the week-end so I'll see what develops, Mates budget is as limited as mine at the moment, coils for the woofer are going to be the limiting factor as he owes me $70- for the mids and his budget is only $100-
New computer and ALL of my old data and projects have been lost.
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