I'm building the ETON 7.3 Kit (ER4 ribbon tweeter, 7-375 mid/bass).
I've assembled a couple of cabinets (one with a rear-facing, 3" flared port, and one with a front-facing, 2" non-flared port as per the plans), and in general I think I'm hearing the promise of some good sound, but right now there are some anomolies.
#1: Midrange boominess. Currently the cabinets aren't finished; the front, back, and sides are glued, with the top and bottom clamped on for testing. They're built with 1" MDF and with 2 horizontal cross-braces, but they aren't yet lined (I've bought some acoustic damping material from parts express), and aren't filled with polyfill. There's also no internal baffle, so there's probably some influence from backwave reflections.
How much do you think each of these are contributing to the midrange problem? I could try some more testing with some polyfill, perhaps, but I don't want to apply the damping mats until I'm sure I'm going to use the cabinets. Hmm, actually I guess I could stick them on with some double sided tape...
#2: Fairly ragged response from 10K to 20K. What could be causing this? Problems with the rear chamber? Baffle step? Non-rounded edges? I added some felt to the chamber, as per the plans, but there's currently a tiny hole for the wires that I haven't plugged. I'm wondering how much this might be affecting the tweeter's performance. I might try just plugging it with clay and measuring again.
Speaking of measuring, I'm using LspCAD 5 with JustMLS. I find the UI and documentation pretty painful, but I'm slowly familiarizing myself with it. I had a difficult time just figuring out how to calibrate JustMLS.
When I tried the 47Kohm + 10Kohm setup mentioned in the manual, the levels were too low even with the volume at max.
So (not having much of a clue what I am doing, in case you haven't guessed by now) I tried tossing the 47Kohm resistor altogether and just leaving the 10Kohm in place across the terminals (and turning the volume back down, of course
). This seemed to give me some meaningful results. When I measured my Paradigm Studio 100's, the response curve looked to be at least in the right ballpark.
My biggest problem remains just how best to do the measurement. Where to place the mic, etc. I'll have to do some more experimentation, but my wife is getting awfully tired of pink noise...
Anyway, I digress. On to the next question:
#3: if I want to diverge from the kit, and start using LspCAD to help with the crossover (assuming I can ever figure out how to do so...), are there inexpensive components that people play with? Experimenting with crossovers looks like it can get to be fairly expensive. Or should I just optimize the xover in LspCAD and trust what it gives me?
#4: Further to the above, if I start messing with the crossover, should I also experiment with the cabinet? Maybe try the ER4 in an open-baffle mode? Has anyone else done this?
I've assembled a couple of cabinets (one with a rear-facing, 3" flared port, and one with a front-facing, 2" non-flared port as per the plans), and in general I think I'm hearing the promise of some good sound, but right now there are some anomolies.
#1: Midrange boominess. Currently the cabinets aren't finished; the front, back, and sides are glued, with the top and bottom clamped on for testing. They're built with 1" MDF and with 2 horizontal cross-braces, but they aren't yet lined (I've bought some acoustic damping material from parts express), and aren't filled with polyfill. There's also no internal baffle, so there's probably some influence from backwave reflections.
How much do you think each of these are contributing to the midrange problem? I could try some more testing with some polyfill, perhaps, but I don't want to apply the damping mats until I'm sure I'm going to use the cabinets. Hmm, actually I guess I could stick them on with some double sided tape...
#2: Fairly ragged response from 10K to 20K. What could be causing this? Problems with the rear chamber? Baffle step? Non-rounded edges? I added some felt to the chamber, as per the plans, but there's currently a tiny hole for the wires that I haven't plugged. I'm wondering how much this might be affecting the tweeter's performance. I might try just plugging it with clay and measuring again.
Speaking of measuring, I'm using LspCAD 5 with JustMLS. I find the UI and documentation pretty painful, but I'm slowly familiarizing myself with it. I had a difficult time just figuring out how to calibrate JustMLS.
When I tried the 47Kohm + 10Kohm setup mentioned in the manual, the levels were too low even with the volume at max.
So (not having much of a clue what I am doing, in case you haven't guessed by now) I tried tossing the 47Kohm resistor altogether and just leaving the 10Kohm in place across the terminals (and turning the volume back down, of course
). This seemed to give me some meaningful results. When I measured my Paradigm Studio 100's, the response curve looked to be at least in the right ballpark. My biggest problem remains just how best to do the measurement. Where to place the mic, etc. I'll have to do some more experimentation, but my wife is getting awfully tired of pink noise...
Anyway, I digress. On to the next question:
#3: if I want to diverge from the kit, and start using LspCAD to help with the crossover (assuming I can ever figure out how to do so...), are there inexpensive components that people play with? Experimenting with crossovers looks like it can get to be fairly expensive. Or should I just optimize the xover in LspCAD and trust what it gives me?
#4: Further to the above, if I start messing with the crossover, should I also experiment with the cabinet? Maybe try the ER4 in an open-baffle mode? Has anyone else done this?
I think we have a classic case of cart before the horse. You need to finish the cabinets per instructions with lining and allow the drivers to break in. This may very well cure the ills you are decribing. I doubt a properly functioning 7.3 would sound as bad as you are describing, I remember reading good things about it. Only after that can you be sure that you really have a dud on your hands.
(sorry for my english)
hi theloniousbonk,
first point: the rear wave of the wf is dangerous for the ER4!!
close all the holes !
second : are you sure of the colours - ER4 wires terminals ( in phase- out of phase) because the red is "-" and blue/black is "+".
Now some personal considerations:
This kit is not well balanced : I know the ER4 , his potential is much higher. The woofer is too big. Hexacone is good only for 3 ways as woofer ( my friend use 7"wf ,4-300" mid,-ER4 but the mid have some limitations IMHO)
Bad news, sorry.
Regards,
hi theloniousbonk,
first point: the rear wave of the wf is dangerous for the ER4!!
close all the holes !
second : are you sure of the colours - ER4 wires terminals ( in phase- out of phase) because the red is "-" and blue/black is "+".
Now some personal considerations:
This kit is not well balanced : I know the ER4 , his potential is much higher. The woofer is too big. Hexacone is good only for 3 ways as woofer ( my friend use 7"wf ,4-300" mid,-ER4 but the mid have some limitations IMHO)
Bad news, sorry.
Regards,
Thanks for the replies so far. I will hopefully have some more time this weekend to experiment some more with it.
In the meantime, I've routed some roundovers on the baffle, and I'm adding the damping material (Sonic Barrier from Parts Express).
I'll plug that hole in the tweeter, but it's a very small hole (approximately equivalent to a couple of 1/8" drill holes), plus there's all that felt stuffed behind the tweeter, so I didn't think back pressure would be a huge issue for the short time I was testing them, although with a $300 tweeter, I really shouldn't take any chances. I'll plug it with clay while I'm testing, and then some caulk in the final assembly.
Yeah, I had the polarity of both speakers correct. I had even tried switching the polarity of the tweeter in case it was mislabeled in the crossover schematic, and got the expected dip in the xover region.
In the meantime, I've routed some roundovers on the baffle, and I'm adding the damping material (Sonic Barrier from Parts Express).
I'll plug that hole in the tweeter, but it's a very small hole (approximately equivalent to a couple of 1/8" drill holes), plus there's all that felt stuffed behind the tweeter, so I didn't think back pressure would be a huge issue for the short time I was testing them, although with a $300 tweeter, I really shouldn't take any chances. I'll plug it with clay while I'm testing, and then some caulk in the final assembly.
Yeah, I had the polarity of both speakers correct. I had even tried switching the polarity of the tweeter in case it was mislabeled in the crossover schematic, and got the expected dip in the xover region.
(sorry for my english)
Well, if all are O.K. this is the sound of the kit!
You are a fine listener and your doubts about the sound quality are right, in my opinion.
Maybe some little adyustments are possible but not big "revolutions"!
I think you can add a midrange instead of the tw and place the ER4
out of the cabinet (on the top) with a rear "nautilus - pipe".
You can use for example a MDM55 or similar .
But you can use also a Fostex 3" with a little rear volume.........
Oh , am I " out of thread" ?
Regards
Well, if all are O.K. this is the sound of the kit!
You are a fine listener and your doubts about the sound quality are right, in my opinion.
Maybe some little adyustments are possible but not big "revolutions"!
I think you can add a midrange instead of the tw and place the ER4
out of the cabinet (on the top) with a rear "nautilus - pipe".
You can use for example a MDM55 or similar .
But you can use also a Fostex 3" with a little rear volume.........
Oh , am I " out of thread" ?
Regards
An update: at long last I have completed the speakers! Thankfully, my original fears are gone. That original boominess I was hearing must have been due to a few factors:
I built these speakers for my brother, so the hardest thing is going to be saying goodbye to them.
Pics are up at http://TheloniousBonk.smugmug.com/Hobbies, in the "Speaker Project #3" gallery. Feel free to peruse my other newbie projects as well... (Tip: when viewing a gallery, switch the view style to "Journal" in the options at the top of the page).
- the cabinets weren't complete at the time, and I had just clamped the tops & bottoms on
- I hadn't put the dampening material in yet
- break-in?
I built these speakers for my brother, so the hardest thing is going to be saying goodbye to them
. Pics are up at http://TheloniousBonk.smugmug.com/Hobbies, in the "Speaker Project #3" gallery. Feel free to peruse my other newbie projects as well... (Tip: when viewing a gallery, switch the view style to "Journal" in the options at the top of the page).
I did measure the speaker, using lspcad (via the JustMLS app), but I closed the app without saving the results (and discovered, to my horror, that justmls just quietly quits without prompting for you to save anything). I didn't feel like doing it all again. The results showed two nicely flat curves for the two drivers, and I don't remember what the xover point was. (At this point I'm still more of an "assembler" than a true DIY speaker builder, so forgive me ).
If (when?) I get around to building a set for myself, I suspect I'll do another set of measurements. I had a difficult time getting my Creative Labs card properly calibrated, and never quite trusted the results, especially in the low frequencies. One of these days I'll pick up an m-audio card and give it another shot.
At any rate, as I said the sound is excellent. The ER4 surprised me. I was prepared to be underwhelmed, and wasn't sure how I'd feel about a $300 tweeter. But after a few nights listening to it, I'm a believer. Without stooping to too much stereophile-ish hyperbole, the high end is more "real" than the tweeter on my Paradigm 100's (this was especially evident when listening to a few tracks on the excellent Burmester sampler CD #3), and the low end of the 7-375 driver meshes very well with my Adire Tempest sub. My brother also has a decent sub, so these should be a great fit for him as well.
).If (when?) I get around to building a set for myself, I suspect I'll do another set of measurements. I had a difficult time getting my Creative Labs card properly calibrated, and never quite trusted the results, especially in the low frequencies. One of these days I'll pick up an m-audio card and give it another shot.
At any rate, as I said the sound is excellent. The ER4 surprised me. I was prepared to be underwhelmed, and wasn't sure how I'd feel about a $300 tweeter. But after a few nights listening to it, I'm a believer. Without stooping to too much stereophile-ish hyperbole, the high end is more "real" than the tweeter on my Paradigm 100's (this was especially evident when listening to a few tracks on the excellent Burmester sampler CD #3), and the low end of the 7-375 driver meshes very well with my Adire Tempest sub. My brother also has a decent sub, so these should be a great fit for him as well.
killing the rear wave
(sorry for my english)
Hi ralphs99,
The first step is hear the difference from one ER4 "closed"(as like the 7.3 kit) VS one ER4 with the rear wave absorbed. A little rear box totally stuffed is enough 1 liter . Obviously the roll-on of the tweeter frequency response is different so you will develope a new high pass
filter. The second step could be replace the rear wall (of the little box)
with 1-2 cm of wool felt .
The finally step could be similar to the Nautilus concept but there is some problems. The propagations must be only axial and I have a big membrane rectangular vs. a little circular (nautilus)! Maybe a eliptic tapered tube
....maybe an internal division of the initial part....not so simply without
adeguate analysis instruments.
Anyway the step 1 and 2 is easy and the difference you can hear is big. Do not try with a PVC tube instead of the little-box: very bad result!
Note only the Aura 1" (and 2" ) at the moment coul be to permit a "nautilus-clone" , but only for the braves!
Regards
(sorry for my english)
Hi ralphs99,
The first step is hear the difference from one ER4 "closed"(as like the 7.3 kit) VS one ER4 with the rear wave absorbed. A little rear box totally stuffed is enough 1 liter . Obviously the roll-on of the tweeter frequency response is different so you will develope a new high pass
filter. The second step could be replace the rear wall (of the little box)
with 1-2 cm of wool felt .
The finally step could be similar to the Nautilus concept but there is some problems. The propagations must be only axial and I have a big membrane rectangular vs. a little circular (nautilus)! Maybe a eliptic tapered tube
....maybe an internal division of the initial part....not so simply without
adeguate analysis instruments.
Anyway the step 1 and 2 is easy and the difference you can hear is big. Do not try with a PVC tube instead of the little-box: very bad result!
Note only the Aura 1" (and 2" ) at the moment coul be to permit a "nautilus-clone" , but only for the braves!
Regards
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.