BHD,
Sounds like everything is working out well ............ huge relief for me. When I wrote the article I intended it to be just a study and design guide. I never suspected that anybody would build the design so quickly. The fact that it seems to be performing will with budget drivers is really great news. You must be really pushing the speakers hard to get the Fostex to shout. Try some acoustic jazz. Some piano trio, some horns, something non-electric to see how they perform.
Your story about the fire department coming cracked me right up. It reminded me of the night many years ago when some buddies and I were tossing back a few and listening to some music at my dive apartment. When I came out of the bathroom I found the East Hartford police standing in the middle of the room checking things out. The older cop was disgusted and gave me a hard time. The younger cop was enjoying the music and was heard to say "Great system!". They did not run us in, asked us to turn it down, and pretty much ended the night ...... until we went out. But that was a long long time ago.
Sounds like everything is working out well ............ huge relief for me. When I wrote the article I intended it to be just a study and design guide. I never suspected that anybody would build the design so quickly. The fact that it seems to be performing will with budget drivers is really great news. You must be really pushing the speakers hard to get the Fostex to shout. Try some acoustic jazz. Some piano trio, some horns, something non-electric to see how they perform.
Your story about the fire department coming cracked me right up. It reminded me of the night many years ago when some buddies and I were tossing back a few and listening to some music at my dive apartment. When I came out of the bathroom I found the East Hartford police standing in the middle of the room checking things out. The older cop was disgusted and gave me a hard time. The younger cop was enjoying the music and was heard to say "Great system!". They did not run us in, asked us to turn it down, and pretty much ended the night ...... until we went out. But that was a long long time ago.
Hi all,
I have a pair of Coral Flat 10s and would like to try it in such a design. The flat 10s are ~95db but MJK's design puts it at ~89db.
How feasble is it to use 2 Eminence 15A per side?
I'm thinking that by keeping the baffle dimensions, FR driver placement and xo points the same, I only need to modify the low pass crossover for a 4ohm load for the woofers with everything else kept the same.
The net effect is a +6db at 95db with lower distortion in the nether regions of sound. Would appreciate any comments on this plan, thanks!
I have a pair of Coral Flat 10s and would like to try it in such a design. The flat 10s are ~95db but MJK's design puts it at ~89db.
How feasble is it to use 2 Eminence 15A per side?
I'm thinking that by keeping the baffle dimensions, FR driver placement and xo points the same, I only need to modify the low pass crossover for a 4ohm load for the woofers with everything else kept the same.
The net effect is a +6db at 95db with lower distortion in the nether regions of sound. Would appreciate any comments on this plan, thanks!
Hey, have some faith, we did!
The funny thing is that while you were replying to my last post, we were listening to Miles Davis's "Kind of Blue" and it sounded GREAT.
The treble is opening right up. The upper midrange is still a little bit forward, but these are Fostex drivers, they have a reputation of taking a long time to break in.
When the firemen came downstairs into the basement, they freaked out - they smelled the burning wood from my circular saw. They started pounding on doors and we came out and told them what we were doing and they were like "hey, look at this, they're building speakers!" and were totally cool with it. They had on the full regalia with oxygen tanks and everything, but all they said was that we might want to try cutting the wood outside next time. Cool guys, they were.
Well, now we're going to turn the wick up a bit with some Primus...
Wish us luck.
Oh, and thanks, Martin. You're the greatest.
I am truly impressed by these speakers. Elegant design. Simple construction. The sound is amazing so far, but be prepared to play with placement in room. I will try to get more seat time with them soon, but pre-term labor is keeping me by the wife's bed in hospital.
Thanks Martin!
best regards,
PSz.
Thanks Martin!
best regards,
PSz.
I could not see a reason it would not work Martin. I am a believer in Lpads (ok let the purist start their thing). If you incorporate an Lpad on the mid/upper driver it can give a great deal of versitility in the applications. The 103 is a really good driver(once broken in) and i even used it in my first horn design, great presence and soundstage and could do a true piano sound. Only drawback is SPL levels without loading. IMHO the 127 with an Lpad would work better.
ron
But that was a long long time ago.
Happens to me about once /month. Nothing like horns to bring the cops out of the Dunkin Donuts.
Those alpha 15's are doing most of the grunt work that would otherwise upset the fe103's. It would take quite a bit to get them out of shape in this design. And, FWIW nobody that has heard them so far said anything about ringing low frequencies. They are not audiophiles though (yet). The biggest "complaint" was how strange it was to hear the room disappear. Music coming from behind the rear wall, etc.
I will strongly recommend breaking in the fe103s before hooking them up to the crossover. IMHO it would take a LONG time to break them in due to the low excursion required of them in this case.
best regards,
PSz.
I will strongly recommend breaking in the fe103s before hooking them up to the crossover. IMHO it would take a LONG time to break them in due to the low excursion required of them in this case.
best regards,
PSz.
PSz.,
That is a great idea and should really speed along the break-in process.
Sounds like you have had some success with the design, thanks for the feedback.
Something tells me that your free time is about to take a serious hit, but it is well worth it. I have three and there was a period when I had no time or energy for speaker building, then a few years later they would sit and listen with me, and now they request I remove myself from their site and go listen to my stereo. Got lotsa free time now, they would not be caught dead listening to my music.
That is a great idea and should really speed along the break-in process.
Sounds like you have had some success with the design, thanks for the feedback.
Something tells me that your free time is about to take a serious hit, but it is well worth it. I have three and there was a period when I had no time or energy for speaker building, then a few years later they would sit and listen with me, and now they request I remove myself from their site and go listen to my stereo. Got lotsa free time now, they would not be caught dead listening to my music.
ronc,
You never know, I was working with manufacturer's specs. The driver could have sounded like crap, hard to believe from Fostex but you never know.
There are a lot of options that could be taken in driver selection and SPL tuning. I just went as cheap and simple as possible. I think the FE-108EZ would be a great choice, but the cost was a bit higher. Any of the Fostex driver I listed in the Table in the article are candidates, just a question of what you want to spend and possibly revising the high pass crossover components slightly for a different driver.
You never know, I was working with manufacturer's specs. The driver could have sounded like crap, hard to believe from Fostex but you never know.
There are a lot of options that could be taken in driver selection and SPL tuning. I just went as cheap and simple as possible. I think the FE-108EZ would be a great choice, but the cost was a bit higher. Any of the Fostex driver I listed in the Table in the article are candidates, just a question of what you want to spend and possibly revising the high pass crossover components slightly for a different driver.
will try to get more seat time with them soon, but pre-term labor is keeping me by the wife's bed in hospital.
I have never had the experience. Never had children, I am envious, but i gave up on things to achieve, maybe my legacy will be safer bridges or ships or pipelines or even better sounding horns and such.
Enjoy your life, its short.
ron
I have never had the experience. Never had children, I am envious, but i gave up on things to achieve, maybe my legacy will be safer bridges or ships or pipelines or even better sounding horns and such.
Enjoy your life, its short.
ron
Greets!
When I was messing with OB I did like Carver and mass loaded them to lower Fs, raise Qts and used multiple drivers to get back the lost efficiency. As MJK's work shows, baffle size is inversely proportional to rising Qts, so Carver raised his to >3 to allow a narrow baffle, then used several to make a line array with the trade-off being a low required XO point due to the increased break-up modes of such stiff cones. With today's ultra high excursion, low Fs sub drivers, relatively cheap high power prosound amps and digital EQ though, why bother unless you have a bunch of cheap drivers laying around collecting dust?
GM
When I was messing with OB I did like Carver and mass loaded them to lower Fs, raise Qts and used multiple drivers to get back the lost efficiency. As MJK's work shows, baffle size is inversely proportional to rising Qts, so Carver raised his to >3 to allow a narrow baffle, then used several to make a line array with the trade-off being a low required XO point due to the increased break-up modes of such stiff cones. With today's ultra high excursion, low Fs sub drivers, relatively cheap high power prosound amps and digital EQ though, why bother unless you have a bunch of cheap drivers laying around collecting dust?
GM
Thanks GM!
I've just been itching for something different to do with my fe108esigma's. But here in germany there is absolutely 0 high Qts bass drivers! The eminence alpha 15 is nowhere to be found and when you do find it they say it is no longer imported! There is another 15 incher with Qts of 1.43 but sensitivity of 88db for 29 euro!
There are a couple of Qts .43 15 inchers that have an fs of 25Hz and frequency range of 40-5000Hz at 98db for 88euro.
Then you go to some lovely monocors and more eminence etc.
Strange I know but hey.... the U.S. is just much cheaper and has more choice.
Cheers Stroop
I've just been itching for something different to do with my fe108esigma's. But here in germany there is absolutely 0 high Qts bass drivers! The eminence alpha 15 is nowhere to be found and when you do find it they say it is no longer imported! There is another 15 incher with Qts of 1.43 but sensitivity of 88db for 29 euro!
There are a couple of Qts .43 15 inchers that have an fs of 25Hz and frequency range of 40-5000Hz at 98db for 88euro.
Then you go to some lovely monocors and more eminence etc.
Strange I know but hey.... the U.S. is just much cheaper and has more choice.
Cheers Stroop
I've a nagging question about reccomended qt for dipole bass driver. This seems to contradict some current advice.
Linkwitz's (http://www.linkwitzlab.com/faq.htm#Q10)reccomendation of qts 0.5-0.8
Dick olsher's reccomendation of qts 0.6-0.7 in his review of Visaton's NoBox BB kit (http://www.enjoythemusic.com/Magazine/equipment/0606/visation_nobox_bb_loudspeaker.htm)
My personal experience with a 2x4' baffle and Ciare CH250 with added magnet (qts 1.1?) gives some what tubby bass, not as tight as i would like. I happen to link orion's bass and would like something as close as possible (since im too cheap to make the orions)
Is it a matter of design requirements and/or preference? I know it would be easier to just try it out but there's no stocks for eminance 15a here yet so i've time to ponder
Linkwitz's (http://www.linkwitzlab.com/faq.htm#Q10)reccomendation of qts 0.5-0.8
Dick olsher's reccomendation of qts 0.6-0.7 in his review of Visaton's NoBox BB kit (http://www.enjoythemusic.com/Magazine/equipment/0606/visation_nobox_bb_loudspeaker.htm)
My personal experience with a 2x4' baffle and Ciare CH250 with added magnet (qts 1.1?) gives some what tubby bass, not as tight as i would like. I happen to link orion's bass and would like something as close as possible (since im too cheap to make the orions)
Is it a matter of design requirements and/or preference? I know it would be easier to just try it out but there's no stocks for eminance 15a here yet so i've time to ponder
I think the point you are missing is the requirement for a second amp. I believe the first two speaker systems you mentioned use a seperate amp for the bass driver, this allows you to turn up the boost to make up for the falling low frequency response inherent in a lower Qts driver in a narrow baffle. You apply more power to the driver to raise the SPL to achieve decent bass and match the efficiency of the mid or full range driver. The displacement requirement for the low frequency driver also rises. If you have two amps, an EQ, and an active crossover this works.
The thrust of my article was to design a completely passive two way OB speaker system at a modest price (cheap). For this type of speaker system I believe that the only way of achieving decent bass in a reasonably sized baffle is with an efficient woofer with a Qts value above 1.0. A lower Qts driver will be rolling off the low frequencies, couple that to a small baffle and the bass starts to suffer significantly.
You cannot compare multi-amp OB systems with single amp designs, the requirements for the woofer drivers will be different and more limiting for the passive system
Just as an aside, in my biamped OB system I still use two Alpha 15A drivers per side and the entire set-up is driven by SS amps. I have not heard any looseness or tubby sound in the bass. I believe the bass from my bi-amped OB's easily reaches down to 40 Hz and probably lower.
Correction :
The Visatron No Box does not require two amps. But to get 40 Hz bass you need a current amp, in this case Nelson Passes F2 amp. If you use a conventional amp the low frequency response is not that great as seen in the SPL measurements. So I would still conclude that the higher Qts woofer driver would be a better candidate if a typical voltage amp is to be used.
The Visatron No Box does not require two amps. But to get 40 Hz bass you need a current amp, in this case Nelson Passes F2 amp. If you use a conventional amp the low frequency response is not that great as seen in the SPL measurements. So I would still conclude that the higher Qts woofer driver would be a better candidate if a typical voltage amp is to be used.
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