Puzzle Coat and L-Pads
Well, my buddy Jase installed the L-Pads on the FE103E's earlier this week.
Since he's a bass head, he had the mid-tweeters turned way down so that the speakers sounded horribly muddy. I turned them back up to a more reasonable level with them turned down just a little bit. They sounded better, but were still a bit shouty.
We disconnected the drivers and I mixed up a 50/50 solution of puzzlecoat and water. I then applied two thin coats to the front side of the driver cones. On the first coat on the first driver I didn't mix the goop well enough and it made it a bit watery, so it soaked through the cone in places, making it look a bit blotchy. I mixed it up a bit and the next one turned out perfect. The stuff dries pretty fast, and we hooked them up after maybe 20 minutes.
I'm fully aware that when you make a change to your system, the sound will be different and the novelty will make you think it's "better". I listened to the drivers before coating them through an entire CD to make sure that I was reasonably familiar with their sound. They're not at my place, so I'm not acclimated to them.
Even though these are relatively inexpensive drivers, I was concerned that I would ruin them by putting goop on them. I figured that it might improve one aspect of the sound, only to ruin another. There had to be a downside, I thought.
I was wrong. There is no downside. Every aspect improved. Most, but not all of the shouty character went away. I would absolutely recommend this to anyone building this speaker. It is a dirt cheap way to improve these little full range drivers, minimizing their weaknesses while keeping almost all of their strengths.
Buy the smallest bottle of puzzlecoat you can find. The brand Mod Podge is available from amazon, but I found it in several art supply and also craft stores. It's cheap and the bottle I bought will treat approximately ten thousand drivers. Make sure that you mix the solution well.
I can hardly wait for my phase plugs to get here! Over the long weekend I hope to try enabl on the woofers and I will report back with results.
Well, my buddy Jase installed the L-Pads on the FE103E's earlier this week.
Since he's a bass head, he had the mid-tweeters turned way down so that the speakers sounded horribly muddy. I turned them back up to a more reasonable level with them turned down just a little bit. They sounded better, but were still a bit shouty.
We disconnected the drivers and I mixed up a 50/50 solution of puzzlecoat and water. I then applied two thin coats to the front side of the driver cones. On the first coat on the first driver I didn't mix the goop well enough and it made it a bit watery, so it soaked through the cone in places, making it look a bit blotchy. I mixed it up a bit and the next one turned out perfect. The stuff dries pretty fast, and we hooked them up after maybe 20 minutes.
I'm fully aware that when you make a change to your system, the sound will be different and the novelty will make you think it's "better". I listened to the drivers before coating them through an entire CD to make sure that I was reasonably familiar with their sound. They're not at my place, so I'm not acclimated to them.
Even though these are relatively inexpensive drivers, I was concerned that I would ruin them by putting goop on them. I figured that it might improve one aspect of the sound, only to ruin another. There had to be a downside, I thought.
I was wrong. There is no downside. Every aspect improved. Most, but not all of the shouty character went away. I would absolutely recommend this to anyone building this speaker. It is a dirt cheap way to improve these little full range drivers, minimizing their weaknesses while keeping almost all of their strengths.
Buy the smallest bottle of puzzlecoat you can find. The brand Mod Podge is available from amazon, but I found it in several art supply and also craft stores. It's cheap and the bottle I bought will treat approximately ten thousand drivers. Make sure that you mix the solution well.
I can hardly wait for my phase plugs to get here! Over the long weekend I hope to try enabl on the woofers and I will report back with results.
Martin i looked at the dashed red line in fig. 6 and while it looks right to me
for a speaker with a high qts, it certainly does not correspond to the graph
given by emminence with their driver. their graph shows a real flat curver
from about 40 hz on up. where did you obtain your curve? thanks again.
for a speaker with a high qts, it certainly does not correspond to the graph
given by emminence with their driver. their graph shows a real flat curver
from about 40 hz on up. where did you obtain your curve? thanks again.
The curve includes the floor reinforcement, the crossover, and a listening position off axis from the woofer. It is a calculated curve. If you look at Figure 4, the dashed blue curve shows an infinite baffle response but still off axis hence the slight falling response as frequency increases. This is also a calculated curve but probably closer to the Eminence curve.
open baffles nice , very nice
FINALLY got them done. I had a wiring glitch which kept me from listening
for a half hour after I had them wired up. This allowed me to listen to the
bass circuit only. Now I understand why a 2nd order xover was employed
instead of a 1st order; I definitely wouldn't want the alpha driver to go higher than it already does.
The speakers ( unfortunately not mine) are being driven by a 6v6 dared integrated
amplifier. The cd played is a Heart 6000. Tomorrow I shall have a Panasonic
receiver so i should be able to put 100-200 watts per channel to them. The little amp drives them surprisingly well, so much so that I am almost afraid to change
it out. I definitely have to wick it up a bit on the volume compared to my
Fe164 bass reflexes. I suggest 30-40 watts at least.
The little fostex cones were treated with two coats of thinned modpodge.
I also did this mod to my fe164 speakers and liked the change very muçh.
A sealed sub is added to the bottom with the control set at 50 hz. The
speakers are run from the 4 ohm taps. I did not bother to try the 8 ohms.
The sound is crisp but smooth; at least as good as i expected and they
are not close to being broken in ( sorry, I am one of those people who
(really) believes that speakers break in. I am hoping that the balance
will change a bit after the woofers loosen up as I do find the treble to
be a bit too much.
Despite the great distance between the two drivers, they blend very well
together. the sound is not as direct and pure as my singledrivers, but
the tone and detail are better than 95% of the open baffles I have heard.
I would rather have the Bastanis Prometheus speakers than these, but
then one is talking alot more money and a much larger size. The sound
quality of the two drivers is different. The fostex offers a very clean and
crisp sound while the woofer is muddier and looser. I fully expect that
the class d receiver will do ALOT to firm up the bass while (hopefully) not
ruining the good qualities of the fostex driver.
Thankyou very much Martin. Anyone wishing to ask me about these terrific
speakers is free to contact me sundbyd2-at-gmail.com
I am amazed that a speaker of this caliber can be designed and work so
well without building , testing, and modding a dozen prototypes. My hat '
is off to Martin King.
FINALLY got them done. I had a wiring glitch which kept me from listening
for a half hour after I had them wired up. This allowed me to listen to the
bass circuit only. Now I understand why a 2nd order xover was employed
instead of a 1st order; I definitely wouldn't want the alpha driver to go higher than it already does.
The speakers ( unfortunately not mine) are being driven by a 6v6 dared integrated
amplifier. The cd played is a Heart 6000. Tomorrow I shall have a Panasonic
receiver so i should be able to put 100-200 watts per channel to them. The little amp drives them surprisingly well, so much so that I am almost afraid to change
it out. I definitely have to wick it up a bit on the volume compared to my
Fe164 bass reflexes. I suggest 30-40 watts at least.
The little fostex cones were treated with two coats of thinned modpodge.
I also did this mod to my fe164 speakers and liked the change very muçh.
A sealed sub is added to the bottom with the control set at 50 hz. The
speakers are run from the 4 ohm taps. I did not bother to try the 8 ohms.
The sound is crisp but smooth; at least as good as i expected and they
are not close to being broken in ( sorry, I am one of those people who
(really) believes that speakers break in. I am hoping that the balance
will change a bit after the woofers loosen up as I do find the treble to
be a bit too much.
Despite the great distance between the two drivers, they blend very well
together. the sound is not as direct and pure as my singledrivers, but
the tone and detail are better than 95% of the open baffles I have heard.
I would rather have the Bastanis Prometheus speakers than these, but
then one is talking alot more money and a much larger size. The sound
quality of the two drivers is different. The fostex offers a very clean and
crisp sound while the woofer is muddier and looser. I fully expect that
the class d receiver will do ALOT to firm up the bass while (hopefully) not
ruining the good qualities of the fostex driver.
Thankyou very much Martin. Anyone wishing to ask me about these terrific
speakers is free to contact me sundbyd2-at-gmail.com
I am amazed that a speaker of this caliber can be designed and work so
well without building , testing, and modding a dozen prototypes. My hat '
is off to Martin King.
Attachments
BHD said:Just wait 'till you try phase plugs...
Mwhahahahahahahahahhaaaaahhhhh...
you got yours installed?
dave
Thanks, I am glad it worked out so well. I think when you go to a SS amp you will find that the bass will tighten up and everything will sound better.
My goal in running simulations is to get the design to 90% of the potential of the drivers or better and then tweak the rest of the way to the final optimum result. As I learn more the simulations become more accurate. I cannot imagine just jumping in and building something without first running simulations, but that is just me. My next OB designs have the simulations done already and will go on to the build/measurement phase and then get documented .... as soon as I find the time.
Alright, here goes...
The FE103's with puzzlecoat (mod podge) sounded much better than stock, but all you had to do was move your head a couple of inches to either side and the high end went away, period. To their credit and much to my suprise, adding the layers of puzzlecoat gave significantly MORE treble, which I suppose shouldn't have been the case since I was adding mass to the cone. But the decay of high notes went on much further than before on acoustic guitar and cymbals. I know it sounds weird, but it really did this. But it was like listening to an old pair of Quads, it was absolutely a "one man speaker". You either kept your head still or you didn't get the magic.
Phase plugs changed all this. The soundstage GREW. There was more treble. You could shift left and right in your chair till you were ready to fall over - and while there was still a "sweet spot", it was much wider and someone sitting 20-30 degrees off axis could still enjoy a lot of what the person in the sweet spot was getting.
To be fair, it wasn't the only modification that was performed. I put ductseal on the transition between basket and magnet to make the air movement out the back of the driver more aerodynamic and my buddy Jase chamfered out the 'till then flat walled holes for the FE103e drivers via a loaned Dremel moto tool (thanks, Dylan!). In a perfect world, we would have done each modification and then listened to them. Sorry, but I don't have that level of patience.
One thing that has been consistent with every modification has been the ability to turn up the volume higher before the dreaded Fostex "shout" kicks in. The FE103e is absolutely incredible with acoustic guitar, vocals and any transients that might come from any drum thats higher in frequency. The other aspect that I've noticed is the high level of "intelligibility" of lyrics with these drivers. There have been at least a dozen occasions while listening where I've been startled by lyrics that are incredibly easily understood with these drivers that have been completely obscured from understanding with more conventional speakers.
I have purposely limited my access to these speakers so that I don't get acclimatized to them. I want to hear what they do, warts and all. I've been very skeptical of claims that Fostex drivers take a long time to break in, but after this experience, I now know it to be true. My ears have not "gotten used" to these drivers - I don't live with them - but the changes have been obvious.
Another factor is the Eminence Alpha 15 woofer. While I was there, the woofer was doing all kinds of weird stuff - peaking here, sucking out there, much different than the last time I heard it. I think this woofer is taking a very long time to break in. When you put your hand on the woofer, its barely moving at all. I'm going to try to procure a SS reciever and pump some really loud 20Hz tones through that woofer for a week or two.
With all these changes, the basic nature has not really changed. There is a point where you turn the volume up... up... and then the cones "go bananas" and start to distort, and the dreaded "Fostex shout" manifests itself with no mercy. With every modification this point has been pushed higher and higher. I'm hoping that with with the EnABL mods I'll push the envelope further, that the drivers will be able to handle even more input before they lose control.
One realization that came to me this weekend was that with the addition of the phase plugs and other mods, I felt that this speaker went from an interesting experiment to a real contender. It sounds GREAT. No, it doesn't have bass down to 20Hz, but it was fun to listen to with everything that we threw at it - Riener, PIL, Monk, it was FUN TO LISTEN TO.
What more could you want?
NEXT STOP, ENABL...
The FE103's with puzzlecoat (mod podge) sounded much better than stock, but all you had to do was move your head a couple of inches to either side and the high end went away, period. To their credit and much to my suprise, adding the layers of puzzlecoat gave significantly MORE treble, which I suppose shouldn't have been the case since I was adding mass to the cone. But the decay of high notes went on much further than before on acoustic guitar and cymbals. I know it sounds weird, but it really did this. But it was like listening to an old pair of Quads, it was absolutely a "one man speaker". You either kept your head still or you didn't get the magic.
Phase plugs changed all this. The soundstage GREW. There was more treble. You could shift left and right in your chair till you were ready to fall over - and while there was still a "sweet spot", it was much wider and someone sitting 20-30 degrees off axis could still enjoy a lot of what the person in the sweet spot was getting.
To be fair, it wasn't the only modification that was performed. I put ductseal on the transition between basket and magnet to make the air movement out the back of the driver more aerodynamic and my buddy Jase chamfered out the 'till then flat walled holes for the FE103e drivers via a loaned Dremel moto tool (thanks, Dylan!). In a perfect world, we would have done each modification and then listened to them. Sorry, but I don't have that level of patience.
One thing that has been consistent with every modification has been the ability to turn up the volume higher before the dreaded Fostex "shout" kicks in. The FE103e is absolutely incredible with acoustic guitar, vocals and any transients that might come from any drum thats higher in frequency. The other aspect that I've noticed is the high level of "intelligibility" of lyrics with these drivers. There have been at least a dozen occasions while listening where I've been startled by lyrics that are incredibly easily understood with these drivers that have been completely obscured from understanding with more conventional speakers.
I have purposely limited my access to these speakers so that I don't get acclimatized to them. I want to hear what they do, warts and all. I've been very skeptical of claims that Fostex drivers take a long time to break in, but after this experience, I now know it to be true. My ears have not "gotten used" to these drivers - I don't live with them - but the changes have been obvious.
Another factor is the Eminence Alpha 15 woofer. While I was there, the woofer was doing all kinds of weird stuff - peaking here, sucking out there, much different than the last time I heard it. I think this woofer is taking a very long time to break in. When you put your hand on the woofer, its barely moving at all. I'm going to try to procure a SS reciever and pump some really loud 20Hz tones through that woofer for a week or two.
With all these changes, the basic nature has not really changed. There is a point where you turn the volume up... up... and then the cones "go bananas" and start to distort, and the dreaded "Fostex shout" manifests itself with no mercy. With every modification this point has been pushed higher and higher. I'm hoping that with with the EnABL mods I'll push the envelope further, that the drivers will be able to handle even more input before they lose control.
One realization that came to me this weekend was that with the addition of the phase plugs and other mods, I felt that this speaker went from an interesting experiment to a real contender. It sounds GREAT. No, it doesn't have bass down to 20Hz, but it was fun to listen to with everything that we threw at it - Riener, PIL, Monk, it was FUN TO LISTEN TO.
What more could you want?
NEXT STOP, ENABL...
class d amplification of the open baffles
the speakers were hooked up for one whole day to the sa xr55 100 watt
per channel home receiver. at that point, we plugged them back into
the 12 watt per channel dared 6v6 amp. the dared just gives a more
musical presentation and a better balance of the bass to the mid/highs.
the panasonic offered a much cleaner and tighter bass, which was a
most welcome improvement. the opportunity to equalize the bass
meant that we could ditch the sub used with the dared. 5 db was
added to the bass at 50 hz., and I adjusted this by the timbre or tone
of the bass rather than by quantity of low bass.
the reason i think that the bal. was better with the dared is that there
is less distortion with a big class d driving the bass, and more harmonic
distortion, perhaps some from clipping, always makes it sound like there
is MORE bass. The little dared had it all over the inexpensive panny
in the mids and highs. The larger amp definitely had greated dynamics
but in the end, the threadbare sound of this particular class d lost out
to the harmonically richer 6v6.
I would love to employ a little 6v6 ( i also have a voice of music 1448
modded to be just an amplifier) on the top and the panny on the
bottom when I get my wright sound preamp back from wright, using
the two outputs on the pre and the existing passive crossovers on
the alpha/fostex open baffles.
Once again, a big thankyou to Martin for making this design available
and for all of his great work in modelling loudspeakers. You have
saved a whole forest of trees.
the speakers were hooked up for one whole day to the sa xr55 100 watt
per channel home receiver. at that point, we plugged them back into
the 12 watt per channel dared 6v6 amp. the dared just gives a more
musical presentation and a better balance of the bass to the mid/highs.
the panasonic offered a much cleaner and tighter bass, which was a
most welcome improvement. the opportunity to equalize the bass
meant that we could ditch the sub used with the dared. 5 db was
added to the bass at 50 hz., and I adjusted this by the timbre or tone
of the bass rather than by quantity of low bass.
the reason i think that the bal. was better with the dared is that there
is less distortion with a big class d driving the bass, and more harmonic
distortion, perhaps some from clipping, always makes it sound like there
is MORE bass. The little dared had it all over the inexpensive panny
in the mids and highs. The larger amp definitely had greated dynamics
but in the end, the threadbare sound of this particular class d lost out
to the harmonically richer 6v6.
I would love to employ a little 6v6 ( i also have a voice of music 1448
modded to be just an amplifier) on the top and the panny on the
bottom when I get my wright sound preamp back from wright, using
the two outputs on the pre and the existing passive crossovers on
the alpha/fostex open baffles.
Once again, a big thankyou to Martin for making this design available
and for all of his great work in modelling loudspeakers. You have
saved a whole forest of trees.
Attachments
IMHO to really move a large cone it takes power. Its a simple power requirement to move a given mass a given distance in a given time and mantain cone control.(overshoot). I am still a fan of the older Marantz 22xx or Mac amps as they tend to get close to a tube sound with lots of smooth punch.
Yes, dont overlook the 103. It was my first FR driver and i remember how different , and better, it sounded than the old Jensen HUGE 3 way studio monitors that i had at the time(real lease breakers). However forget real bass with just the 103 in a horn or otherwise.
I added an Lpad to Martins OB and yes it was better, but still lacked that LF slam that i get from my old Dallas I with the 208.
ron
Yes, dont overlook the 103. It was my first FR driver and i remember how different , and better, it sounded than the old Jensen HUGE 3 way studio monitors that i had at the time(real lease breakers). However forget real bass with just the 103 in a horn or otherwise.
I added an Lpad to Martins OB and yes it was better, but still lacked that LF slam that i get from my old Dallas I with the 208.
ron
mjk design
The speakers are breaking in very nicely; I have yet to biamp them
but will have my preamp with it's two sets of outputs up and running
shortly, and shall report on the result.
Although I am enjoying these speakers very much, there are still a
couple aspects of the design that i don't understand. First, how can
the crossover be designed by merely plugging in the 8 ohm figure for
each of the drivers? the impedance must surely vary alot in the 200-
400 hz. range, and each driver must have a different curve than the
other.
Secondly, Mr. King stresses the importance of having a significantly more
efficient woofer than the mid/tweeter for a 2way passive OB system.
yet when one looks at the response curve for the woofer on usspeakers.com,
it holds very near the 90 db. output level at the freqencies at which is
is used.
Martin?
The speakers are breaking in very nicely; I have yet to biamp them
but will have my preamp with it's two sets of outputs up and running
shortly, and shall report on the result.
Although I am enjoying these speakers very much, there are still a
couple aspects of the design that i don't understand. First, how can
the crossover be designed by merely plugging in the 8 ohm figure for
each of the drivers? the impedance must surely vary alot in the 200-
400 hz. range, and each driver must have a different curve than the
other.
Secondly, Mr. King stresses the importance of having a significantly more
efficient woofer than the mid/tweeter for a 2way passive OB system.
yet when one looks at the response curve for the woofer on usspeakers.com,
it holds very near the 90 db. output level at the freqencies at which is
is used.
Martin?
Re: mjk design
The crossovers were not designed assuming a perfect 8 ohm resistance for the drivers. The actual driver impedance curve was used to size the crossover filters. But in the range 200 to 400 Hz both drivers have impedances close to the voice coil's DC resistance which helps simplify the crossover, notice that no Zobels of resonance traps were applied across the driver treminals. All of this work was done in a custom version of the MathCad two driver OB worksheet that includes passive crossover capabilities.
My own measurements of the Alpha 15A produce a 92.4 dB/W/m result. That is consistent with the blue dashed curve in Figure 4. Since the Qts is ~ 1.2, there will be a slight peak near resonance which brings the driver up to about 95 dB/W/m. So when you cross them over low the effective working efficiency is higher due to the hump in the SPL response. It is all about optimizing and mating two drivers with an OB, something that most people ignore when they trial and error a design with uncompatible drivers.
Hope that helps,
mor2bz said:
The crossovers were not designed assuming a perfect 8 ohm resistance for the drivers. The actual driver impedance curve was used to size the crossover filters. But in the range 200 to 400 Hz both drivers have impedances close to the voice coil's DC resistance which helps simplify the crossover, notice that no Zobels of resonance traps were applied across the driver treminals. All of this work was done in a custom version of the MathCad two driver OB worksheet that includes passive crossover capabilities.
My own measurements of the Alpha 15A produce a 92.4 dB/W/m result. That is consistent with the blue dashed curve in Figure 4. Since the Qts is ~ 1.2, there will be a slight peak near resonance which brings the driver up to about 95 dB/W/m. So when you cross them over low the effective working efficiency is higher due to the hump in the SPL response. It is all about optimizing and mating two drivers with an OB, something that most people ignore when they trial and error a design with uncompatible drivers.
Hope that helps,
biamping the mjk open baffle two-way
yes! I had the speakers hooked up to my wright preamp driving the bass
with the panny xr55, and the mid/treble was driven with the amp section of
a modified voice of music 1448 (pp miniature 6v6).
this combo worked very well, although the highs were rolled off somewhat
from when i used the dared 6v6. this setup allowed for a more relaxed sound
from the fostex drivers, and a cleaner sound from the 15" drivers. the bass was firmer and more extended as i bumped up the freq. @ 50 hz. 5 db. it was great to control the vol. of the bass amp while the other remained at a set level. this allowed one to add a little bass at just the right frequencies ( 300 and under) on those re-
cordings that were bass light, and to lower the bass on those recordings
that were bass heavy. the treble and mids were much smoother and more
listenable than using the panny on both the top and bottom. the best of
both worlds, really. I know that this system was meant to get around the
need to biamp, but i just had to try it as i had the equipment.
it seemed like the further away from the speakers i got, the better they sounded.
i don't think that this is a great nearfield setup on account of the distance
between the two drivers. The further away i got, the better the sound was
blended from the drivers. i believe that the height of the fostex driver was
chosen to place it at ear height when seated, and the position of the bass driver
was place low for optimum output. when i played a Tim Berne (tenor sax, i believe) cd, there was a passage where he would alternate notes several
octaves apart, and this really sounded unusual, with the sound first emanating
from high in the speaker and then a couple feet lower.
Martin, if i were to mount the fosted driver near the eminence and tilt the baffle back to project the treble up to ear level, should i leave the top of the baffle intact?
or could i lower it within five inches of the top of the fostex driver as it is now
and still preserve the bass balance and reinforcement?
thankyou very much.
the rest of the
yes! I had the speakers hooked up to my wright preamp driving the bass
with the panny xr55, and the mid/treble was driven with the amp section of
a modified voice of music 1448 (pp miniature 6v6).
this combo worked very well, although the highs were rolled off somewhat
from when i used the dared 6v6. this setup allowed for a more relaxed sound
from the fostex drivers, and a cleaner sound from the 15" drivers. the bass was firmer and more extended as i bumped up the freq. @ 50 hz. 5 db. it was great to control the vol. of the bass amp while the other remained at a set level. this allowed one to add a little bass at just the right frequencies ( 300 and under) on those re-
cordings that were bass light, and to lower the bass on those recordings
that were bass heavy. the treble and mids were much smoother and more
listenable than using the panny on both the top and bottom. the best of
both worlds, really. I know that this system was meant to get around the
need to biamp, but i just had to try it as i had the equipment.
it seemed like the further away from the speakers i got, the better they sounded.
i don't think that this is a great nearfield setup on account of the distance
between the two drivers. The further away i got, the better the sound was
blended from the drivers. i believe that the height of the fostex driver was
chosen to place it at ear height when seated, and the position of the bass driver
was place low for optimum output. when i played a Tim Berne (tenor sax, i believe) cd, there was a passage where he would alternate notes several
octaves apart, and this really sounded unusual, with the sound first emanating
from high in the speaker and then a couple feet lower.
Martin, if i were to mount the fosted driver near the eminence and tilt the baffle back to project the treble up to ear level, should i leave the top of the baffle intact?
or could i lower it within five inches of the top of the fostex driver as it is now
and still preserve the bass balance and reinforcement?
thankyou very much.
the rest of the
Mathscad Exp8 speed
I tried the sample work sheet using the MathCad Explorer8 from MJK's site . The graphs updated themselves ( not fast at all !) as I scrolled down but when I reached the "part2 - Detailed SPL response section " it took a very long time ( several minutes) to plot the first couple of graphs. Then when I scrolled further downwards it plotted the others much faster though still not as fast as I would expect from a 1.5gig CPU.
My computer has an AMD Sempron running at 1.5GHz. 512 Mb Ram.
Is this normal ?
I tried the sample work sheet using the MathCad Explorer8 from MJK's site . The graphs updated themselves ( not fast at all !) as I scrolled down but when I reached the "part2 - Detailed SPL response section " it took a very long time ( several minutes) to plot the first couple of graphs. Then when I scrolled further downwards it plotted the others much faster though still not as fast as I would expect from a 1.5gig CPU.
My computer has an AMD Sempron running at 1.5GHz. 512 Mb Ram.
Is this normal ?
Greets!
It takes awhile, though back when I had a slow machine I found that un-checking the math auto calc and instead clicked on 'calculate worksheet' when I wanted to refresh it seemed a little faster and saves time lost scrolling to make each section do its calculating.
GM
It takes awhile, though back when I had a slow machine I found that un-checking the math auto calc and instead clicked on 'calculate worksheet' when I wanted to refresh it seemed a little faster and saves time lost scrolling to make each section do its calculating.
GM
Greetings everyone
Somehow with the pressures of running business I missed this thread, what a blow. Holidays are now upon me and I am excited by the new possibilities here.
I found the article fascinating as I have been running an analogue based open baffle system based on heavily modded 4 inch drivers and bass reinforcement for about 8 months now and remain totally mesmerized by the sound but I never really could work out why.
Here is a link to some pics of the drivers in progress, further modded now though:
http://homepage.mac.com/braddles/Menu2.html
Many mates have heard the system and all have commented on the accuracy, live feeling, dynamics etc, but because most OB proponents were going down the pathway of big full rangers I thought I must have been missing something, or my ears were deceiving me.
I have tried larger drivers but none have the "real being there" sound of the 4s. I have not used Fostex 103s but I do now have 4 Foster 103s that I will enable and mod to try out on the OBs.
Just a couple of ideas that may be worth trying:
My 4 inch drivers are not actually baffle mounted, instead they are mounted via the magnets to stands and sit in an opening behind the main baffle, the speakers have small light ply baffles that extend 2 inches or so around the front of the basket, so I get a better interface with the main baffle. Curiously I feel this actually reinforces the mid bass a bit to.
The bass drivers are mounted in sealed boxes, that are aimed downwards to the floor (wedged). I would be interested to try the approach of this thread instead, but I must say this is pretty effective though it should be noted I am using bi-amping.
I wonder how it might work if the 15 drivers were aimed at the floor wedge style but with the backs still open of course, so they rear wave was directed more towards the ceiling/corner of the room?
I really feel from my experience the concept of 4 inch 90db driver and very efficient big woofer is great and makes terrific sense, after all the whole idea is about achieving balance not just volume. In any case the OBs seem quite a bit louder than non-horn boxed type systems.
I have also added peizo tweeters, properly crossed over up high, both rear and front firing variants and this worked a treat, peizos done well in this application are much better than they have any right to be, though now I think I am just going to have to enable the cones in them.
Somehow I get the feeling that OB is about to have a bit of a tech driven resurgence and that is a pretty good thing in my book so a big thanks to Martin for his work.
Somehow with the pressures of running business I missed this thread, what a blow. Holidays are now upon me and I am excited by the new possibilities here.
I found the article fascinating as I have been running an analogue based open baffle system based on heavily modded 4 inch drivers and bass reinforcement for about 8 months now and remain totally mesmerized by the sound but I never really could work out why.
Here is a link to some pics of the drivers in progress, further modded now though:
http://homepage.mac.com/braddles/Menu2.html
Many mates have heard the system and all have commented on the accuracy, live feeling, dynamics etc, but because most OB proponents were going down the pathway of big full rangers I thought I must have been missing something, or my ears were deceiving me.
I have tried larger drivers but none have the "real being there" sound of the 4s. I have not used Fostex 103s but I do now have 4 Foster 103s that I will enable and mod to try out on the OBs.
Just a couple of ideas that may be worth trying:
My 4 inch drivers are not actually baffle mounted, instead they are mounted via the magnets to stands and sit in an opening behind the main baffle, the speakers have small light ply baffles that extend 2 inches or so around the front of the basket, so I get a better interface with the main baffle. Curiously I feel this actually reinforces the mid bass a bit to.
The bass drivers are mounted in sealed boxes, that are aimed downwards to the floor (wedged). I would be interested to try the approach of this thread instead, but I must say this is pretty effective though it should be noted I am using bi-amping.
I wonder how it might work if the 15 drivers were aimed at the floor wedge style but with the backs still open of course, so they rear wave was directed more towards the ceiling/corner of the room?
I really feel from my experience the concept of 4 inch 90db driver and very efficient big woofer is great and makes terrific sense, after all the whole idea is about achieving balance not just volume. In any case the OBs seem quite a bit louder than non-horn boxed type systems.
I have also added peizo tweeters, properly crossed over up high, both rear and front firing variants and this worked a treat, peizos done well in this application are much better than they have any right to be, though now I think I am just going to have to enable the cones in them.
Somehow I get the feeling that OB is about to have a bit of a tech driven resurgence and that is a pretty good thing in my book so a big thanks to Martin for his work.
freq response measurements
here is what i got with the cheapo ratshack analog meter at about 8 ft with
the bass boosted 5 db at aprox. 50 hz. (boost curve unknown)
40hz 74db
50 82
63 84
80 81
100 82
125 81
160 82
200 82
250 81
315 79
400 79
500 80
630 82
800 80
1000 77
1250 79
1600 79
2000 77
2500 77
3150 79
4000 81
5000 82
6300 79
8000 71
10000 62
12500 55
I was very surprised to see how smoothly they measured in the bass and mids.
Not that they didn't sound smooth in those regions. I was equally surprised at
how rolled off the treble was; this was with two LIGHT coats of modpodge on the
fostex driver. Would someone care to comment on my request as to whether
or not to keep the upper portion of the panels if i lower the fostex driver down
near the alpha 15 for better integration between the drivers? thanks
here is what i got with the cheapo ratshack analog meter at about 8 ft with
the bass boosted 5 db at aprox. 50 hz. (boost curve unknown)
40hz 74db
50 82
63 84
80 81
100 82
125 81
160 82
200 82
250 81
315 79
400 79
500 80
630 82
800 80
1000 77
1250 79
1600 79
2000 77
2500 77
3150 79
4000 81
5000 82
6300 79
8000 71
10000 62
12500 55
I was very surprised to see how smoothly they measured in the bass and mids.
Not that they didn't sound smooth in those regions. I was equally surprised at
how rolled off the treble was; this was with two LIGHT coats of modpodge on the
fostex driver. Would someone care to comment on my request as to whether
or not to keep the upper portion of the panels if i lower the fostex driver down
near the alpha 15 for better integration between the drivers? thanks
Re: freq response measurements
Hi,
If I understand correctly the modelling is the baffle is mirrored in the
floor so is effectively 76" x 20" with "two" 15" drivers near the floor.
I cannot see that a < 20% reduction in height would cause problems.
🙂/sreten.
mor2bz said:
Hi,
If I understand correctly the modelling is the baffle is mirrored in the
floor so is effectively 76" x 20" with "two" 15" drivers near the floor.
I cannot see that a < 20% reduction in height would cause problems.
🙂/sreten.
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