DC resistance?
OK, I have some FE103 (and 40-1197), some plywood, and I'm building a microphone amplifier to go with my loudspeaker measuring system tomorrow. I could buy a pair of the bass drivers. What DC resistance are the crossover chokes? I have various reels of enamelled copper wire and can easily design and build the inductors, then trim their inductance to the required value on the bridge.
OK, I have some FE103 (and 40-1197), some plywood, and I'm building a microphone amplifier to go with my loudspeaker measuring system tomorrow. I could buy a pair of the bass drivers. What DC resistance are the crossover chokes? I have various reels of enamelled copper wire and can easily design and build the inductors, then trim their inductance to the required value on the bridge.
I used the values on the Parts Express data sheets in my simulations.
9 mH ---> 0.35 ohms
4 mH ---> 0.22 ohms
Hope that helps,
9 mH ---> 0.35 ohms
4 mH ---> 0.22 ohms
Hope that helps,
Impressions, a week and a half later...
Well, I hadn't gone over to my buddy's place to hear the MJK open baffle speakers since the Sunday before last - he's been running them constantly while he's been at work, at times running the 103's full range and the woofer with the crossover while he's gone. I went over there yesterday and here are my updated impressions:
They've improved, but not much. They still tend to be a bit "tinny" and can get shrill if pushed really hard. These qualities varied greatly depending on which recording we played, but I think it had more to do with the level of certain frequencies in the recordings rather than the quality of the recordings themselves. This lends me to believe that the driver is peaking at certain frequencies, something that isn't surprising, really. I went into this knowing that it would likely take a long breaking in period before these drivers sounded their best. Treble is there, but "airy" is not a term I'd use to describe these speakers. Bass is not as deep as I would like, but is it ever? The issues with bass probably have more to do with placement and the proximity of furniture than anything else.
On the positive side, imaging is very good, with lots of depth to the sound. Dynamics are amazingly good, and this is a very rhythmic and involving loudspeaker - making you want to listen despite their flaws. The reproduction of transient sounds, such as plucked strings and drums, is close to the best if not the best I've ever heard. It sounds very "electrostatic like" if you get my drift, and another aspect I like about it is that it sounds like it's "cut of one cloth" if that makes any sense.
I might add that beer helps the sound, good beer helps even more and strong Belgian beer appears to help the most.
I'd like to wait a while before modifying the drivers too much, but my friend really wants to get going (he has to live with them, after all). So here's what I'm going to do near term:
Round the rear edge of the baffle holes for the 103 drivers to allow for easier air flow.
Damp the frame of the driver and make the air flow easier, as per planet 10's mods.
Planet 10 phase plugs, of course!
At that point I may let the drivers break in a little more. In the meantime, I'll probably build a really nice 3/4 inch baffle with solid bracing. Right now the base is attached to the baffle via two "L" brackets to allow for easy modification of "tilt" and the wood thickness is 1/2 inch ply. Once I install the drivers in the better baffle (say it ten times fast, it's fun!), I'll probably solder most of the crossover components together. Right now they're just screwed together on terminal strips.
After that, I'll look into enable and mamboni mods, but that's a ways off. I really want the changes (hopefully improvements) to be due to the driver modification and not so much to driver break in.
Questions? Suggestions? I'd also love to hear impressions from others that have built this project.
🙂
Well, I hadn't gone over to my buddy's place to hear the MJK open baffle speakers since the Sunday before last - he's been running them constantly while he's been at work, at times running the 103's full range and the woofer with the crossover while he's gone. I went over there yesterday and here are my updated impressions:
They've improved, but not much. They still tend to be a bit "tinny" and can get shrill if pushed really hard. These qualities varied greatly depending on which recording we played, but I think it had more to do with the level of certain frequencies in the recordings rather than the quality of the recordings themselves. This lends me to believe that the driver is peaking at certain frequencies, something that isn't surprising, really. I went into this knowing that it would likely take a long breaking in period before these drivers sounded their best. Treble is there, but "airy" is not a term I'd use to describe these speakers. Bass is not as deep as I would like, but is it ever? The issues with bass probably have more to do with placement and the proximity of furniture than anything else.
On the positive side, imaging is very good, with lots of depth to the sound. Dynamics are amazingly good, and this is a very rhythmic and involving loudspeaker - making you want to listen despite their flaws. The reproduction of transient sounds, such as plucked strings and drums, is close to the best if not the best I've ever heard. It sounds very "electrostatic like" if you get my drift, and another aspect I like about it is that it sounds like it's "cut of one cloth" if that makes any sense.
I might add that beer helps the sound, good beer helps even more and strong Belgian beer appears to help the most.
I'd like to wait a while before modifying the drivers too much, but my friend really wants to get going (he has to live with them, after all). So here's what I'm going to do near term:
Round the rear edge of the baffle holes for the 103 drivers to allow for easier air flow.
Damp the frame of the driver and make the air flow easier, as per planet 10's mods.
Planet 10 phase plugs, of course!
At that point I may let the drivers break in a little more. In the meantime, I'll probably build a really nice 3/4 inch baffle with solid bracing. Right now the base is attached to the baffle via two "L" brackets to allow for easy modification of "tilt" and the wood thickness is 1/2 inch ply. Once I install the drivers in the better baffle (say it ten times fast, it's fun!), I'll probably solder most of the crossover components together. Right now they're just screwed together on terminal strips.
After that, I'll look into enable and mamboni mods, but that's a ways off. I really want the changes (hopefully improvements) to be due to the driver modification and not so much to driver break in.
Questions? Suggestions? I'd also love to hear impressions from others that have built this project.
🙂
I am buiding an OB based on Fostex FE167E as the mid-range driver, without any mods, it can sound a little thin. I think it is typical of Fostex on OB without mods.
I also used 2*12in bass drivers for the bass and made some measurements, I didn't like what I get, the response is not good, I change to U frame, the overall bass response improves dramatically, I introduce have other problems I need to solve.
If you change to a different mid range driver it may sound very different. I have an 8in Hemp full range I still need to try it out.
Overall if you pay just pay $400 for the parts I think it is a bargain. It will beat any system in that price range.
I also used 2*12in bass drivers for the bass and made some measurements, I didn't like what I get, the response is not good, I change to U frame, the overall bass response improves dramatically, I introduce have other problems I need to solve.
If you change to a different mid range driver it may sound very different. I have an 8in Hemp full range I still need to try it out.
Overall if you pay just pay $400 for the parts I think it is a bargain. It will beat any system in that price range.
Re: Impressions, a week and a half later...
When i get a few more pictures together, i've got a thread to start about "extreme basket treatment"
I'd EnABL the driver 1st, then evaluate need for phase plugs... (this comment just for the current FE103/107/126/127), the whizzer drivers definitly need plugs
dave
BHD said:
When i get a few more pictures together, i've got a thread to start about "extreme basket treatment"
I'd EnABL the driver 1st, then evaluate need for phase plugs... (this comment just for the current FE103/107/126/127), the whizzer drivers definitly need plugs
dave
Well, since this is coming from the guy that sells the phase plugs, I guess I'd better listen, eh?
Well, I'm going to order a set for my FE206ES-R's in any case.
🙂
BHD ok i see you are using the atmosphere amp
i had the pleasure of hearing one with a fostex system years ago; nice amp
are you using the 4 ohm taps? have you had a chance to try the pp scott yet?
i am anxious to get my pr up and running thanks for the posts 😕
i had the pleasure of hearing one with a fostex system years ago; nice amp
are you using the 4 ohm taps? have you had a chance to try the pp scott yet?
i am anxious to get my pr up and running thanks for the posts 😕
The Atma-Sphere's don't have taps, so they're running straight in. I figure they're putting out a good 30 watts, so no need to hook up the zero's that my friend has.
I haven't had a chance to do anything with them yet, yesterday was the first time I'd heard them since the very first day. They have real potential, I've been eyeing some of the alternative spendier drivers, but I want to try my hand at modifying the 103's. I think the Scott will be an excellent match for them, it's a 299B that's been upgraded, but not upgraded "too much" if you know what I mean.
🙂
I haven't had a chance to do anything with them yet, yesterday was the first time I'd heard them since the very first day. They have real potential, I've been eyeing some of the alternative spendier drivers, but I want to try my hand at modifying the 103's. I think the Scott will be an excellent match for them, it's a 299B that's been upgraded, but not upgraded "too much" if you know what I mean.
🙂
BHD said:
We have one those (had 2 until the mains trafo on 1 expired filling the house with acrid smoke). It has been stripped and rebuilt as an El Cheapo inspired Class A triode PP with all Solen PS caps in the CLCRC supply. 4 of the most incredible watts you'll hear.
dave
BHD,
I would EnABL both drivers, bass and FR. The bass driver will actually show more "improvement" in whatever constitutes EnABL clarity, than even the Fostex will. Bass with the same transient characteristics and internal detail of instruments as the Fostex, in short.
Bud
I would EnABL both drivers, bass and FR. The bass driver will actually show more "improvement" in whatever constitutes EnABL clarity, than even the Fostex will. Bass with the same transient characteristics and internal detail of instruments as the Fostex, in short.
Bud
Does the "tinny" sound only appear when you are pushing the speaker really hard? Does it go completely away or just become less obvious if you back the level down to a more reasonable listening level. I am assuming you are really pushing the speakers while listening to electronic music. Same thing happen with all acoustic music?
I have never used the FE-103E so I don't have any experience to offer. If the driver is the limiting piece in the design, then I would probably recommend stepping up to the FE-108EZ driver which will be a drop in replacement. I have heard the FE-108EZ and been very impressed with the performance.
I think that the bass will always be limiting if you want output below 50 Hz. Small baffle with all passive crossover will not allow 20 Hz bass output, at least with any of the drivers I have tried in my simulations. The bass from an OB will also be a little different then what is heard from a boxed speaker. The frequencies are there but might not have the "bloom" that is typical of a boxed speaker.
Thanks for the update and keep us posted on your progress.
Hi Martin. Thanks for your efforts!
I have a pair of Fostex 108 sigmas (not EZ) sitting on the shelf. Would these be a drop in replacement as well?
Thanks in advance,
Scott.
I have a pair of Fostex 108 sigmas (not EZ) sitting on the shelf. Would these be a drop in replacement as well?
Thanks in advance,
Scott.
sreten said:
Yes streten, mounted on ceiling and tilted to point to the listening position. Idea to move the speakers out to where there is excess space. Problem being that my ceiling is not too high too, about 2.6m.
MJK said:
Looking at the room, I probably will have to tilt it about 30 degrees if it is going to be about 1m from the rear wall. I think the ceiling then will act like a "rear wall" too yeah so not advisable
What about mounting the woofer sort of parellel to the ceiling but with a angled top(or bottom in this case) to put the full ranger?
Hard to find other suitable woofers besides the eminience 15A!
scott_m said:
The original 108s have about 2 dB on the FE103 or the FE108eS.
It is most likely just the driver running out of steam (modding helps here) but it is also the kind of deficit that Bud's electron pools help out with.
dave
Foolishness!
Appears to provide a sub set of the benefits of a poured ground plane. Specifically, low level coherent dynamic information is pretty drastically increased with an EP on the return lug of a loud speaker. For electronic kit it is a mixed bag. The better the ground plane the less the effect.
An EP from my hands is a 6 inch piece of 140 strands of #40 AWG coil winding cable, with three small pieces of heat shrink tubing. Both ends are tinned and both ends are attached to a ground / return point.
So, a shorted loop of wire with massive surface area, a tiny amount of capacitance in localized places. Other experimenters have tried different schemes with varying results. Only one person, with a thick copper plate in his preamp reported no effect.
A thread with much speculation can be found here.
http://www.diyaudio.com/forums/showthread.php?postid=1213239#post1213239
Bud
MJK said:
Another one of Bud's devices... it substitutes for a poured ground plain in a piece of electronics.
Althou no one has confirmed why, the only reasonable theory i've seen is that it supplies available electrons when a transient momentarily (and you have to think VERY short time spans) exhausts the supply of electrons that are the flow of current.
This theory is backed up somewhat by papers that talk about ground planes in electronics.
It also seems to coincide with the results some people get when they connect the negative of their speaker to the basket -- the basket acts as an electron pool. This is not so common these days but vintage speakers (particularily European ones) came from the factory with a solder tag on the basket.
The clearly audible result is that it allows a dynamic passage to be more easily reproduced without audible strain.
dave
edit: i see Bud & i posted at the same time 🙂
electron pool
This method/device/concept might do something to improve something else, but the "replenishment of spent electron flux" would seem to fly in the face of the band gap theory of metallic conduction (i.e. conduction band is within the available energy band for the electron flow). Given the enormous # of electrons available in a good conductor relative to the flux at any reasonable current density, how could a transient deplete the available electrons?
planet10 said:
This method/device/concept might do something to improve something else, but the "replenishment of spent electron flux" would seem to fly in the face of the band gap theory of metallic conduction (i.e. conduction band is within the available energy band for the electron flow). Given the enormous # of electrons available in a good conductor relative to the flux at any reasonable current density, how could a transient deplete the available electrons?
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