I recycled an enclosure from a less than successful project that I attempted about a year ago. Surprisingly enough the FE207E fit pretty well.
http://www.timn8er.com/alegria_audio_fq.htm
http://www.timn8er.com/alegria_audio_fq.htm
Timn8ter said:
Those look very nice. I noticed that you used the BSC design from Martin King's ML-TL for the FE206/207E. I was currious what you are using to drive this speaker and what value of resistor you have settled upon? Many of the builders of the 206/207 ML TL swear by Mills resitors, what brand are you using?
As for the BSC, do you find that the values for the rectangular enclosure also work for your tappered section?
One last question (for now!) ... What do you estimate your efficiency to be with the stuffing and BSC in place?
Cheers,
GM.
Yes, I used Martin's BSC circuit as described. I used Mills resistors and settled on the 1 ohm. I'm using an EL-34 push-pull amp and don't feel the need to attenuate the mids any further. At this point it seems well balanced. I may change my mind but I'm happy for now. Estimate is right, but I would say they are still more efficient than my 90 db speakers, I guess 92-93db.
It may be a little early to make an objective comparison. I'm still like a kid with a new toy so naturally I think it's great. I like listening to music with a lot of acoustic bass so that was always a short-coming with the FE103E since the best I could hope for was mid to upper 50Hz response. The FE127E is better but doesn't have the power handling I would like. I haven't built anything with the pair of FE167E I have sitting on the shelf and I haven't used the FE207E without the tweeter other than putting my hand over the tweeter while it's playing. All that considered I'm surprised at the overall balance of the FE207E. Just when I wonder if there's enough bass along comes a song like Hot Milk (Monty Meets Sly and Robbie) and I'm pleasently surprised. Details are quite good in the mid-range but I'll have to do an A/B test with the FE103E to be more objective. I've been listening to this setup for about a week and I'm still hearing new things in my music. That's probably a good sign.
Josephjcole said:
Ok Joe, today I did an A/B test between the 207 TQWT and my FE103E bipoles. I chose a couple of acoustic songs without a lot of bass so that wouldn't distract me from concentrating on the mids. Specifically, "God's Song" and "This One's Gonna Bruise" from Beth Orton's Daybreaker LP, English pressing on the Heavenly label. It was not apparent at first but when Beth would hit a lower guitar string the FE103E had a more definite sound to it than the FE207E. Believe me, I had to listen closely several times to notice it but I can't deny that it's there. Additionally, I find the mid-range of the FE207E to be better than the FE127E which may be surprising to some, but that's MHO.
I blocked off the super tweeter, listened for a while then un-blocked it. I noticed ambient things like the decay of a brushed snare drum are much better with the super tweeter but, once again, not obvious unless you're listening closely and enjoy that sort of thing like I do.
I should add that this is a highly subjective comparison and just MHO.
Hello Tim:
I have a couple of questions:
How well did the numbers from the previous project fit the needed specs for the fe207. Do you think that the recycled box optimizes the potential of the driver?
How many hours do you have them so far. I noticed with my fe167's it took a long time before I thought they were broken in and ready for critical listening tests.
Good news about acoustic bass. I love a good stand up bass.
Do you think the drivers will perform better in a tapered pipe or in a MLTL.
By the way: Good for you, I wish I had the time to do what you are doing.
Going to Surrey Nov 20?
I have a couple of questions:
How well did the numbers from the previous project fit the needed specs for the fe207. Do you think that the recycled box optimizes the potential of the driver?
How many hours do you have them so far. I noticed with my fe167's it took a long time before I thought they were broken in and ready for critical listening tests.
Good news about acoustic bass. I love a good stand up bass.
Do you think the drivers will perform better in a tapered pipe or in a MLTL.
By the way: Good for you, I wish I had the time to do what you are doing.
Going to Surrey Nov 20?
I notice in Martin's numbers that he gets a bump at driver resonance which is usually good. According to the graphs the response is a little lower and drops off faster than my TQWT does. Also, the phase graphs on my design seem smoother, probably because I was able to put the driver in the middle of the line rather than towards the top. This is supposed to be better but I've not had the opportunity to listen to Martin's design so it's purely academic. I'll be bringing it to Surrey on the 20th so you can form your own opinion. My hunch is that a cabinet design specifically for the driver rather than one that comes close should be better. I may have 20 hours on them and now I started fiddling with the Isa's again so the 207s are sitting in the corner, but not for long. Thanks for the confidence boost.
I may have 20 hours on them and now I started fiddling with the Isa's again so the 207s are sitting in the corner, but not for long. Thanks for the confidence boost. Hi Tim,
Actually the hump is an artifact of the software and is not real. I have assumed that the driver and the port are coincident, which is obviously not the case. When you factor in the different positions in the simulation, the hump disappears and the slight sag just above it fills in nicely. In the present version of the MathCad worksheets the coincident assumption tends to make the ripples, dips, and bumps a little more pronounced then they are in reality. In my newer versions under development this is taken care of, along with the baffle step calculation, by using the real enclosure geometry.
Actually the hump is an artifact of the software and is not real. I have assumed that the driver and the port are coincident, which is obviously not the case. When you factor in the different positions in the simulation, the hump disappears and the slight sag just above it fills in nicely. In the present version of the MathCad worksheets the coincident assumption tends to make the ripples, dips, and bumps a little more pronounced then they are in reality. In my newer versions under development this is taken care of, along with the baffle step calculation, by using the real enclosure geometry.
Thanks so much for the comparisons Tim! It is supprising that the 207 has a better midrange than the 127. I've always figured the larger drivers gave something up in the midrange/treble to achieve more bass/dynamics. I guess it shouldn't be suprising that such a huge over-simplification doesn't stand up to reality. Anyways they look good and it sounds like they are putting out some good music to boot. Glad you're enjoying them.
Joe
Anyways they look good and it sounds like they are putting out some good music to boot. Glad you're enjoying them.Joe
Hi Tim,
I am very excited about these improvements. On the down side I am not going to make them available for downloading. I continue to find people using my MathCad worksheets for personal gain without remembering where they came from or how much work went into developing the math. So my current thinking is to write the software, show the results and interesting design possibilities, but hold onto the math and the actual worksheets.
I am very excited about these improvements. On the down side I am not going to make them available for downloading. I continue to find people using my MathCad worksheets for personal gain without remembering where they came from or how much work went into developing the math. So my current thinking is to write the software, show the results and interesting design possibilities, but hold onto the math and the actual worksheets.
Hello Martin:
I am with Tim on this one. I think that the service you provide to the DIY community is great. I would hate to see it diminish. Allowing selected licencing of the sheets might be a way to ensure your efforts are fairly compensated and recognised. I for one am happy with the project I completed based on your work. I have heard a few other projects based on your work and have been very impressed. If some people are abusing your magnanimus efforts perhaps focusing in on them is the way to go or structuring a safety net for future efforts is appropriate.
Keep up the good work and thanks for all the help
I am with Tim on this one. I think that the service you provide to the DIY community is great. I would hate to see it diminish. Allowing selected licencing of the sheets might be a way to ensure your efforts are fairly compensated and recognised. I for one am happy with the project I completed based on your work. I have heard a few other projects based on your work and have been very impressed. If some people are abusing your magnanimus efforts perhaps focusing in on them is the way to go or structuring a safety net for future efforts is appropriate.
Keep up the good work and thanks for all the help
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