A quick upgrade to my Buschhorns - the addition of an old metal framed tweeter with it's original passive crossover left in place. The difference is quite noticeable; on good recordings they give extra depth to vocals and cymbals. Don't ask me about their values as I haven't got a clue..
Attachments
Hi Dave, I don't know anything about the tweeter or crossover other than they came from my old Wharefdale Lintons (6 ohm '70s bookshelfs that were always fluffy in the bass but good in the mids and highs).
The crossover is probably overkill so this w/e I might take it out and install just some 3.3 caps that I have laying about. As you say, the 1197s have benefitted from some help in the high frequencies, plus the build quality of these tweeters is sturdy to say the least.
The crossover is probably overkill so this w/e I might take it out and install just some 3.3 caps that I have laying about. As you say, the 1197s have benefitted from some help in the high frequencies, plus the build quality of these tweeters is sturdy to say the least.
Compression Chamber
A quick question about Compression Chamber.
I too build the Buschhorn using 108ESigma and have left the compression chamber as it is. Read from earlier messge that 108ESigma should have a smaller compression chamber and some have mentioned about adding cork sheet or wood to cover it up so as to make the CC smaller.
My question is, what is the effect of a smaller compression chamber?
Thanks.
A quick question about Compression Chamber.
I too build the Buschhorn using 108ESigma and have left the compression chamber as it is. Read from earlier messge that 108ESigma should have a smaller compression chamber and some have mentioned about adding cork sheet or wood to cover it up so as to make the CC smaller.
My question is, what is the effect of a smaller compression chamber?
Thanks.
Re: Compression Chamber
the size of the compression chamber determines the frequency of the low pass on the sound getting into the horn.
Leach defines it as Vb = Vas / ((system resonance grequency/driver resonance frequency)^2 -1) where the frequencies are in radians (the 2pis should cancel so you should be able to just plug in hertz)
Dinsdale as V = c*St/(2*pi*f)
Martin King's (unreleased) horn worksheet actually models it.
Ideally the (low Q) driver is falling off in output at this cutoff frequency, and the length of the horn is an odd number of half-wavelengths at this frequencies so that comb filtering is minimized (ie above this frequency the front of the driver is strong and the horn weak, below it, the horn is strong and the front of the driver rolling off, and at the frequency the horn & driver are in phase (except for the (2n-1)/2 wavelength delay of the signal coming thru the horn).
Leach should get you into the ballpark, and from there you are tuning.
The attached excerpt from Dinsdale gives the rationale...
dave
niteraider said:
the size of the compression chamber determines the frequency of the low pass on the sound getting into the horn.
Leach defines it as Vb = Vas / ((system resonance grequency/driver resonance frequency)^2 -1) where the frequencies are in radians (the 2pis should cancel so you should be able to just plug in hertz)
Dinsdale as V = c*St/(2*pi*f)
Martin King's (unreleased) horn worksheet actually models it.
Ideally the (low Q) driver is falling off in output at this cutoff frequency, and the length of the horn is an odd number of half-wavelengths at this frequencies so that comb filtering is minimized (ie above this frequency the front of the driver is strong and the horn weak, below it, the horn is strong and the front of the driver rolling off, and at the frequency the horn & driver are in phase (except for the (2n-1)/2 wavelength delay of the signal coming thru the horn).
Leach should get you into the ballpark, and from there you are tuning.
The attached excerpt from Dinsdale gives the rationale...
dave
Attachments
And here is Leach's paper...
http://users.ece.gatech.edu/~mleach/papers/HornPaper/HornPaper.pdf
dave
http://users.ece.gatech.edu/~mleach/papers/HornPaper/HornPaper.pdf
dave
The effect of adding a tweeter to the Buschhorn has been a small but noticeable improvement in depth of soundstage, so I was thinking of taking this further by having active tweeters, rather than passive ones as they are now. Does anyone think this would be a worthwhile move?
Also, I need to get some better units as the tweeters I am using are not the best and sound a bit harsh to say the least. Any suggestions for suitable units would be much appreciated - I've read that Vifa D27TG are pretty good for the money (around £35 / $60 each).
Also, I need to get some better units as the tweeters I am using are not the best and sound a bit harsh to say the least. Any suggestions for suitable units would be much appreciated - I've read that Vifa D27TG are pretty good for the money (around £35 / $60 each).
Tweeters?
Ropie, from your photos on post #24 / 25, it looks like you're using RS40-1197 with wooden phase plugs.
When I had my horns, I tried 1197, Dave's secret stash FE103A, and finally Fostex FE108E Sigmas, and tested all with an add-on horn loaded tweeter, rolled in at around 10-12K IIRC ( DAVE - you could probably post a picture of the outrigger).
I generally found the 1197's improved with the tweeter, the Alnicos depending on program material, and the Fostex Sigmas didn't need it at all. My listenening is now almost exclusively under 90dB, so even with only 2W from my EL84 triode monoblocks, with the sensitivity levels of the BHorns and the add on tweeter I didn't find the passive components for the filter compromised things enough to justify an extra amp.
Try a pair of FE108E Sigmas in the B-horns - of course cost more than most budget tweeters, but an outstanding combination - and no filters at all to worry.
.
I sold my pair a few weeks ago, to a very nice home, and am now readjusting to loudspeaker with a much different signature. Heil AMT tweeter with bipole Fostex FW227 bass drivers. Provides a bigger and more romantic presentation, particularly with (passively) bi-amped, but definitely lacking the coherency, palpable midrange and imaging of the single driver.
with apologies, some fragmented song lyrics could summarize:
"it ain't the meat, it's the motion"
and
"too much .(is) .... not enough"
Ropie, from your photos on post #24 / 25, it looks like you're using RS40-1197 with wooden phase plugs.
When I had my horns, I tried 1197, Dave's secret stash FE103A, and finally Fostex FE108E Sigmas, and tested all with an add-on horn loaded tweeter, rolled in at around 10-12K IIRC ( DAVE - you could probably post a picture of the outrigger).
I generally found the 1197's improved with the tweeter, the Alnicos depending on program material, and the Fostex Sigmas didn't need it at all. My listenening is now almost exclusively under 90dB, so even with only 2W from my EL84 triode monoblocks, with the sensitivity levels of the BHorns and the add on tweeter I didn't find the passive components for the filter compromised things enough to justify an extra amp.
Try a pair of FE108E Sigmas in the B-horns - of course cost more than most budget tweeters, but an outstanding combination - and no filters at all to worry.
.
I sold my pair a few weeks ago, to a very nice home, and am now readjusting to loudspeaker with a much different signature. Heil AMT tweeter with bipole Fostex FW227 bass drivers. Provides a bigger and more romantic presentation, particularly with (passively) bi-amped, but definitely lacking the coherency, palpable midrange and imaging of the single driver.
with apologies, some fragmented song lyrics could summarize:
"it ain't the meat, it's the motion"
and
"too much .(is) .... not enough"
Hi Chris,
I'd love to try a pair of FE108Es but would also like to work to get the best from the 1197s. Who knows, maybe if I get round to hearing them with the 108s I'll wonder why I didn't upgrade sooner (financial reasons mainly)!
From what you say it seems that it would not be worth going to the trouble of biamping with tweeters. Did you use one of the Fostex horn tweeters or some other arrangement?
BTW, I too have been messing about with open baffles recently. Would love to know more about your new speakers also.
I'd love to try a pair of FE108Es but would also like to work to get the best from the 1197s. Who knows, maybe if I get round to hearing them with the 108s I'll wonder why I didn't upgrade sooner (financial reasons mainly)!
From what you say it seems that it would not be worth going to the trouble of biamping with tweeters. Did you use one of the Fostex horn tweeters or some other arrangement?
BTW, I too have been messing about with open baffles recently. Would love to know more about your new speakers also.
Break-in
Ropie, even the 1197's probably need several hundred hours to fully break-in, and there are numerous minor tweaks reported at various forums. You've already made the most dramatic physical mod by removing the dustcap and adding the phase plugs.
Some cone treatment and basket dampening ( ductseal ) would be the next to try .
The horn tweeter we used was actually some generic import . I think I've still got the box in my workshop, and Dave can certainly post a picture of same. Actually a very nice sounding little horn, although I never proceeded past the cheap XO parts - I bought the 108's instead.
Best $200 I ever spent
Probably do it all over again, maybe with some slight mods on the enclosure construction. The AMT/Fostex combo just ain't doinit for me
As Dave Cope might say, " I say, you been spoiled boy"
Ropie, even the 1197's probably need several hundred hours to fully break-in, and there are numerous minor tweaks reported at various forums. You've already made the most dramatic physical mod by removing the dustcap and adding the phase plugs.
Some cone treatment and basket dampening ( ductseal ) would be the next to try .
The horn tweeter we used was actually some generic import . I think I've still got the box in my workshop, and Dave can certainly post a picture of same. Actually a very nice sounding little horn, although I never proceeded past the cheap XO parts - I bought the 108's instead.
Best $200 I ever spent
Probably do it all over again, maybe with some slight mods on the enclosure construction. The AMT/Fostex combo just ain't doinit for me
As Dave Cope might say, " I say, you been spoiled boy"
Here is a pic of the MG tweeters... i'm pretty sure you've seen my tweeters of the week page
http://www.t-linespeakers.org/FALL/bd-pipes.html
Horns tend to work pretty well. I speculate that their narrower dispersion is a better match way up where they are working...
dave
http://www.t-linespeakers.org/FALL/bd-pipes.html
Horns tend to work pretty well. I speculate that their narrower dispersion is a better match way up where they are working...
dave
Attachments
If you are going to use a dome, or a variation like these nominal 14mm domes (the 10mm are better), try loading them in a waveguide...
dave
An externally hosted image should be here but it was not working when we last tested it.
dave
Thanks for all that info. Dave, I have spent a lot of time browsing over at t-line.org but had not seen 'tweeter of the week'. I am going to look at some horn tweeters then to see if I can get some for a reasonable price.
Chris, are you Chris who built the Dalines as featured on Dave's pages? If so, I came *this* close to building a pair before I was offered a bargain pair of 1197s to try.
Chris, are you Chris who built the Dalines as featured on Dave's pages? If so, I came *this* close to building a pair before I was offered a bargain pair of 1197s to try.
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