Hi Dan
Thanks for responding and sharing
Your confirmation of the wiring confirms my initial findings with the pair i've acquired.
I was disappointed to discover my new found treasure was missing an eye and the rest (well not all) of the drivers are suffering from stiff dried out supensions and spiders.Which begs me to ask do you know of a good hydroscopic solution for treating the surrounds and spiders with? I'm worried that my attempt restor them to original may fail on the basis of driver availability.
On the subject of drivers i contemplated reloading these boxes with Visaton Fr 13's but they only seem to come in the 4 ohm flavour.I hope we don't wind up bidding against each other trying to buy Hox 22's off ebay.
I'd give anything to hear yours or mine to see if that zigzag baffle produces a cohesive wavefront or if it's riddled with off axis lobing
Thanks for responding and sharing
Your confirmation of the wiring confirms my initial findings with the pair i've acquired.
I was disappointed to discover my new found treasure was missing an eye and the rest (well not all) of the drivers are suffering from stiff dried out supensions and spiders.Which begs me to ask do you know of a good hydroscopic solution for treating the surrounds and spiders with? I'm worried that my attempt restor them to original may fail on the basis of driver availability.
On the subject of drivers i contemplated reloading these boxes with Visaton Fr 13's but they only seem to come in the 4 ohm flavour.I hope we don't wind up bidding against each other trying to buy Hox 22's off ebay.
I'd give anything to hear yours or mine to see if that zigzag baffle produces a cohesive wavefront or if it's riddled with off axis lobing
No one that i know of has found a reliable cure for stiff surround syndrome.
It has been suggested that some oil + solvent could work, the solvent loosening up the offending stuff and then the oil sucking it up (and subsequently removed).
dave
planet 10
i currently don't have a flat bed scanner or i'd copy and make an attempt at posting it here
in the mean time if you could get your hands on a copy of "Audio Cyclopedia" by Howard M. Tremaine and lookup Section 20 page 1117 entry 20.94 and tell me what you think about this info
sincerely
turk 182
( i think i just used an old school URL)
i currently don't have a flat bed scanner or i'd copy and make an attempt at posting it here
in the mean time if you could get your hands on a copy of "Audio Cyclopedia" by Howard M. Tremaine and lookup Section 20 page 1117 entry 20.94 and tell me what you think about this info
sincerely
turk 182
( i think i just used an old school URL)
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I will suggest that this only applies to drivers where the surround is a continuation of the paper cone.
dave
Attachments
thanks planet10
i've used this for paper and cloth/mesh surrounds as well as treating VC spider assemblies.
it's probably not applicable on newer foam or rubber/butyl surrounds but it has helped me with older drivers.
old stiff speakers need not go to the junkbox.
p.s.: i wonder what the difference of using this method compares to adding mass to lower resonance.
i've used this for paper and cloth/mesh surrounds as well as treating VC spider assemblies.
it's probably not applicable on newer foam or rubber/butyl surrounds but it has helped me with older drivers.
old stiff speakers need not go to the junkbox.
p.s.: i wonder what the difference of using this method compares to adding mass to lower resonance.
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well i just reloaded my bifrons boxes with their drivers (post treatment) minus the one i was missing(so i removed 1 from the complete box and used two visaton's to complete the missing driver count) i must say this is a case for sound quality vs measurement.i can't quite put my finger on it but i like how they sound despite what the RTA is telling me.
after listening to all kinds of music tracks on them and playing with positioning i prefer them horizontal with the single driver side facing the wall about a foot and a half out from the wall they rock (for lack of a better descripitive term)!
after listening to all kinds of music tracks on them and playing with positioning i prefer them horizontal with the single driver side facing the wall about a foot and a half out from the wall they rock (for lack of a better descripitive term)!
Hey there Turk. You definitely didn't offend me! I've just been so busy it's crazy.
Good news on the bifrons; sounds like you ended up arranging them exactly as I have mine. In the end the only thing I really had to change about them was the hot mid-range resonances I was getting. I added a ring of putty around the whizzer cone (pressed right into the gap where the voice coil former is visible) as a terminator to damp transverse modes in the cones. This ended up having exactly the desired effect and also reduced fs a bit for better bass response. The only real drawback to this mod is a reduction in efficiency but they are still very efficient.
Good news on the bifrons; sounds like you ended up arranging them exactly as I have mine. In the end the only thing I really had to change about them was the hot mid-range resonances I was getting. I added a ring of putty around the whizzer cone (pressed right into the gap where the voice coil former is visible) as a terminator to damp transverse modes in the cones. This ended up having exactly the desired effect and also reduced fs a bit for better bass response. The only real drawback to this mod is a reduction in efficiency but they are still very efficient.
duo
busy is good i hope that along with the craziness there's cash!
i'm still running the original wiring scheme and drivers (other than the visaton's on the back)
and just a comparision of terms i'd be more apt to say that they have comb filtering happening in the upper mid's which colors them not resonances but i will have to try the putty thing to see.
i'll ask again what is your acoustic resistor for aperiodic tuning?
the next thing i am going to experiment with on these is to rewire them to obtain a more cohesive wave front(the original scheme places the "hot" drivers in series legs at co-incident points which doesn't help)
p.s. : i'm still trying to confirm a rumbling about a low frequency compensation circuit that was built into a companion (matching/intended) amp.
busy is good i hope that along with the craziness there's cash!
i'm still running the original wiring scheme and drivers (other than the visaton's on the back)
and just a comparision of terms i'd be more apt to say that they have comb filtering happening in the upper mid's which colors them not resonances but i will have to try the putty thing to see.
i'll ask again what is your acoustic resistor for aperiodic tuning?
the next thing i am going to experiment with on these is to rewire them to obtain a more cohesive wave front(the original scheme places the "hot" drivers in series legs at co-incident points which doesn't help)
p.s. : i'm still trying to confirm a rumbling about a low frequency compensation circuit that was built into a companion (matching/intended) amp.
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the Bifrons hox-05 is appropriately named!
after listening to these speakers for a couple of months i still couldn't quite figure out what it was about them that made me stop and focus so intently on them.
i've now realized it's the comb filtering!
after a few quick checks with the RTA there's huge notch's in the mid range from aprox. 800 hz up to about 3khz that occur in the 17 to 48 degree region not to mention the 300 hz broad peak that i'm pretty sure is the result of too small a box ,being that it's intended as a sealed enclosure.
after some experimentation (as in running half the box and aperiodic and reflex tuning it; even trying a six inch sub driver in dipole) i'm reasonably certain that without changing the box geometry and implementing the right combination of crossover/eq they are a masterful example of how not to build a speaker!
after listening to these speakers for a couple of months i still couldn't quite figure out what it was about them that made me stop and focus so intently on them.
i've now realized it's the comb filtering!
after a few quick checks with the RTA there's huge notch's in the mid range from aprox. 800 hz up to about 3khz that occur in the 17 to 48 degree region not to mention the 300 hz broad peak that i'm pretty sure is the result of too small a box ,being that it's intended as a sealed enclosure.
after some experimentation (as in running half the box and aperiodic and reflex tuning it; even trying a six inch sub driver in dipole) i'm reasonably certain that without changing the box geometry and implementing the right combination of crossover/eq they are a masterful example of how not to build a speaker!
They do have some funny frequency response effects and a nasty peak in response for sure. I improved mine dramatically by adding mass to the cones of the drivers (I may have mentioned that earlier in this thread).
After adding mass to the drivers I found an aperiodic or sealed enclosure ended up being the best thing. You still get the comb effects and the bass response lacks but regardless of empirical measurements there was a quality about the Bifrons I could never get past; most of my friends had the same impression of them.
After adding mass to the drivers I found an aperiodic or sealed enclosure ended up being the best thing. You still get the comb effects and the bass response lacks but regardless of empirical measurements there was a quality about the Bifrons I could never get past; most of my friends had the same impression of them.
sorry duo you can add whatever you want to the drivers or tune the box how you like; it's a bad design which would make even the best drivers you can find sound like a--!
your right i couldn't get passed the quality of comb filtering !
p.s. the drivers individually in a 1.5 liter enclosure sound awesome!
your right i couldn't get passed the quality of comb filtering !
p.s. the drivers individually in a 1.5 liter enclosure sound awesome!
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