Thanks angchuck! I think you meant the recommended double bass reflex enclosure with somewhat modified dims... and the port on the rear. Looks like you may possibly be correct!
http://www.madisound.com/pdf/fostexdrivers/fe127erev.pdf
Scroll down to see recommended enclosure design. Has anyone compared this to the ref project (simple ported box)?
Peace,
Godzilla
http://www.madisound.com/pdf/fostexdrivers/fe127erev.pdf
Scroll down to see recommended enclosure design. Has anyone compared this to the ref project (simple ported box)?
Peace,
Godzilla
Greets!
Yeah, from a strictly gross Vb POV, it works out if you use thicker material to make it.
GM
Yeah, from a strictly gross Vb POV, it works out if you use thicker material to make it.
GM
Help with folded-n monopole
I built a pair of the folded-n monopoles. Unfortunately they did not turn out very well. The output starts dropping off below 200 Hz (this is just by ear with a tone generator, I don't have any measurement equipment).
I included a 4 dB BSC circuit (designed using Martin King's spreadsheet).
I did make a mistake building the cabinets. I misread the plans and placed the driver 3/4" too high. Is the geometry of the transmission line sensitive enough that this is likely to be my problem?
How low does the range on this speaker usually extend?
I'm trying to decide whether to rebuild the same cabinet correctly, or try one of the other plans for this driver (maybe the Fonkens).
I built a pair of the folded-n monopoles. Unfortunately they did not turn out very well. The output starts dropping off below 200 Hz (this is just by ear with a tone generator, I don't have any measurement equipment).
I included a 4 dB BSC circuit (designed using Martin King's spreadsheet).
I did make a mistake building the cabinets. I misread the plans and placed the driver 3/4" too high. Is the geometry of the transmission line sensitive enough that this is likely to be my problem?
How low does the range on this speaker usually extend?
I'm trying to decide whether to rebuild the same cabinet correctly, or try one of the other plans for this driver (maybe the Fonkens).
I'd say there is something wrong somewhere. The ones we built (Chris' mom's) went well below 100 Hz... 50-65 Hz would be my guess. They use boundary reinforcement for BSC.
dave
dave
I should clarify.
The output goes well below that. It does reach as low as 50-65 Hz. 200Hz is when the output level is noticably lower than higher frequencies.
Is that normal? I was hoping for something flat to at least 80 Hz.
The output goes well below that. It does reach as low as 50-65 Hz. 200Hz is when the output level is noticably lower than higher frequencies.
Is that normal? I was hoping for something flat to at least 80 Hz.
To get "flat" you need to deal with baffle-step somehow...
http://www.t-linespeakers.org/tech/bafflestep/intro-bds.html
dave
http://www.t-linespeakers.org/tech/bafflestep/intro-bds.html
dave
Try pulling the BSC out of circuit and playing with room placement / mounting height.
The pair I built for mom were raised only a few inches off the floor and tilted back at about 5`. Situated near a back wall this provides some decent boundary reinforcement (1/4 space), as well as pleasant soundstage height presentation.
FWIW, I've played these and a series of FE126 horn designs on a limited number of amp types,(SE and PP EL84 tubes, mini-aleph SS, and of course mom's 80's vintage HK receiver). None were more than 30w, all with great results. While the low damping factor SE tube amps may have added some bloom and weight to the bass over the mini-aleph, I think it'd be fair to say they are not particularly fussy about amp "matching".
As for Dave's comments on dealing with baffle step, at the risk of repeating myself, I've found the easiest way to do that is bi-pole. If your listening room is of sufficient dimensions that the monopole has deficiencies, then you could have enough space for the bipole to come into its own.
The pair I built for mom were raised only a few inches off the floor and tilted back at about 5`. Situated near a back wall this provides some decent boundary reinforcement (1/4 space), as well as pleasant soundstage height presentation.
FWIW, I've played these and a series of FE126 horn designs on a limited number of amp types,(SE and PP EL84 tubes, mini-aleph SS, and of course mom's 80's vintage HK receiver). None were more than 30w, all with great results. While the low damping factor SE tube amps may have added some bloom and weight to the bass over the mini-aleph, I think it'd be fair to say they are not particularly fussy about amp "matching".
As for Dave's comments on dealing with baffle step, at the risk of repeating myself, I've found the easiest way to do that is bi-pole. If your listening room is of sufficient dimensions that the monopole has deficiencies, then you could have enough space for the bipole to come into its own.
I believe my < 200 Hz frequency response is beyond what can be accounted for by baffle step considerations. Either the driver just doesn't extend low enough to be usable at those frequencies or I screwed up big time on the enclosure.
It sounds like people are pretty happy with this speaker even without a subwoofer, so I am guessing it is the latter.
So, rebuild the same enclosure? or a different one? Decisions, decisions.
It sounds like people are pretty happy with this speaker even without a subwoofer, so I am guessing it is the latter.
So, rebuild the same enclosure? or a different one? Decisions, decisions.
preiter said:
100 hours is just starting to get broken in, but certainly enuff that the bass should have loosened up.
dave
I've got a pair of 127s on their way here now and planning on building the folded monopole design, so hearing of a audible drop in spl below 200hz is a bit concerning. Dave, forgive me but Im not sure what "boundary reinforcement" means. I think I remember you saying your folded monopoles sounded great without a BSC circuit, so I assume boundary reinforcement is an alternative.
Also Im curious if you (Dave) agree with Chris that the Fonkens will get better sound out of the 127s than the folded monopole design. I prefer the aesthetics over the fonkens and the simplicity of the woodwork, but if the fonkens sound significantly better then maybe I should give them a try?
Thanks for your help guys, looking forward to having some decent speakers.
Also Im curious if you (Dave) agree with Chris that the Fonkens will get better sound out of the 127s than the folded monopole design. I prefer the aesthetics over the fonkens and the simplicity of the woodwork, but if the fonkens sound significantly better then maybe I should give them a try?
Thanks for your help guys, looking forward to having some decent speakers.
stelleg151 said:
Boundary reinforcement is a fancy name for getting them close to a wall which acts as an extended baffle... as these were implemented we actually used the floor & the wall. (the exectution was inspired by the Fostex recommended FE126 TL/BR hybrid)
The Fonkens out perform the ML-TL. They have better control & finesse in the bass. We asked the same question, "is it worth dealing with the extra complexity of the Fonken over the diyA ML-TL" -- so we arranged & did the compare.
dave
Attachments
Ok sounds good, I guess if you think its worth the loss in sound for the simplicity and aesthetics then it will be worth it for me since I dont have much skill with wood.
Thanks again for the help.
Thanks again for the help.
I've finally got my hands on a pair of Fe127E (7 week wait from Wilmslow audio) and am going to try out the folded monopoles asap. mainly because the WAF is a bit higher than the Fonkens.
I'll post my implementation when it's done / broken in...
Dave, in your experience how close to the back wall is optimal for the ML-TL?
Cheers,
gus
I'll post my implementation when it's done / broken in...
Dave, in your experience how close to the back wall is optimal for the ML-TL?
Cheers,
gus
Our implementation, so far, seems fairly unique. When i heard them in Chris' living room they were arraryed across a corner, and out from the wall 2' (60 cm) at the most. Our version is close to the ground, and the angled placement with respect to the walls and corners plays a role. Chris can comment on their siting at his mom's.
There was no lack of bass, but it did have some bloom. If you are using a SS amp some of this bloom should dry-up a bit as the amp takes gretter control of the speaker, but it will also likely get a bit leaner (even our SS amps lean towards lower damping)
dave
There was no lack of bass, but it did have some bloom. If you are using a SS amp some of this bloom should dry-up a bit as the amp takes gretter control of the speaker, but it will also likely get a bit leaner (even our SS amps lean towards lower damping)
dave
Cheers,
I'll be using my Charlize to drive the monoploes, so should be lots of control. Wall placement will be about 1.5' from the back wall and 8-10' away from the corners. I'll most likely put them on small (~6") angled stands. I'll keep you posted...
Gus
I'll be using my Charlize to drive the monoploes, so should be lots of control. Wall placement will be about 1.5' from the back wall and 8-10' away from the corners. I'll most likely put them on small (~6") angled stands. I'll keep you posted...
Gus
planet10 said:
Yes definately, sorry if I implied otherwise, I wouldnt be building them if I didnt have some faith in your opinion. 🙂
Anyways, one question I have is how long is the interior wall?
If that unclear, Im referring to the board that the arrow is pointing to.
An externally hosted image should be here but it was not working when we last tested it.
Just eyeballing it, it looks like it should be around 8", but I wanted to check in case that isnt drawn quite to scale.
Thanks a bundle