Ghee... 30 minute limit for editing...
Bob... i now remember why i tried the mltl worksheet first. On the Metronome website it's stated that the Metronome behaves much like a TQWT which is modelled with the mltl worksheet according to MJK.
And if i understand Scottmoose correctly he says something similar on page one of this thread (but i could be wrong with that).
So the question is how big the differences really are. Probably someone else simulated it with different worksheets?
Bob... i now remember why i tried the mltl worksheet first. On the Metronome website it's stated that the Metronome behaves much like a TQWT which is modelled with the mltl worksheet according to MJK.
And if i understand Scottmoose correctly he says something similar on page one of this thread (but i could be wrong with that).
So the question is how big the differences really are. Probably someone else simulated it with different worksheets?
Another follow-up on the F120a Mets.
Being disappointed in the F120a drivers, I decided to run a sim in MJK's MLTL worksheet to see if the FE127e would work in the Met designed for the F120a. It looks good to me. 😀
Comparing this result to a sim run with the dimensions from the Met tables on the Frugel Horn site: the larger Met for the F120a is tuned a few Hz lower than the one given in the Met tables, so you get a few more Hz extension in the bass; otherwise, essentially no difference.
Bottom line: I think I'll get another pair of FE127e's, stick them in the spiffy new Mets, then see if I can unload the F120a's.
Cheers, Jim
Being disappointed in the F120a drivers, I decided to run a sim in MJK's MLTL worksheet to see if the FE127e would work in the Met designed for the F120a. It looks good to me. 😀
Comparing this result to a sim run with the dimensions from the Met tables on the Frugel Horn site: the larger Met for the F120a is tuned a few Hz lower than the one given in the Met tables, so you get a few more Hz extension in the bass; otherwise, essentially no difference.
Bottom line: I think I'll get another pair of FE127e's, stick them in the spiffy new Mets, then see if I can unload the F120a's.
Cheers, Jim
Hi Bob, wow, a Qts of .26 (vs. .18 on the factory spec sheet). .26 is what the FE207E is what the FE207E is supposed to be. Do you recall offhand your measured Qts for the FE207E?
Also, may I ask which Smith & Larson you're getting? (I have a Dayton Woofer Tester 3, and it's pretty flimsy.)
My average for a half dozen 207's is 0.32.
The S&L products have absolutely nothing to do with the Dayton knock-off. You should have paid the 50% premium to get the real thing. Oh, well....
I got the Speaker Tester. I can't justify the Woofer Tester Pro.
Bob
The S&L products have absolutely nothing to do with the Dayton knock-off. You should have paid the 50% premium to get the real thing. Oh, well....
I got the Speaker Tester. I can't justify the Woofer Tester Pro.
Bob
Bob Brines said:
Ok... with these specs a much taller enclosure (75 inch internal height) is needed for max flat extension than with the FE207E (Assumption made that the mltl worksheet can be used to model a Metronome).
Efficiency suffers as well, because of needed serial resistance.
An externally hosted image should be here but it was not working when we last tested it.
OK, but do you really want a max-flat alignment? IMO this just leads to a boomy sounding speaker. I prefer a EBS type alignment like this:
Trust me. This give PLENTY of bass.
Bob
An externally hosted image should be here but it was not working when we last tested it.
Trust me. This give PLENTY of bass.
Bob
Bob Brines said:
I think it depends on the kind of music you normally listen to. Tbh, i would prefer a higher tuning to limit excursion in the 60 Hz - 100 Hz range with some roll off below 50 Hz, because i mainly listen to rock music (i know that fullrangers aren't naturally suited to this kind of music, but i like the simplicity of such builds). With the FE206E the enclosure can be much smaller than with this max flat simulation i posted, but it probably is still bigger than the FE207E Metronome, but with less extension and less excursion.
After all i'm still learning how to work with the worksheets, so probably i'll find a simulation that fits my needs better than the already modelled ones, and isn't that one of the best things in diy? Build your own speaker according to your needs and preferences? 🙂
The issue I am raising here is room lift. Unless you are going to use your speakers in a really large room, you are going to get some room lift at the bottom. It acts as if you are using bass boost. Suppose that you will get 10dB of lift at 30Hz. Add 10dB to your plot. Is that going to sound bass heavy or even "one-note bass"?. Add 10 dB to the bottom of my plot and the speaker is darn near flat in-room to 30Hz.
See what I mean?
Bob
See what I mean?
Bob
I'm with Bob on this; a max flat (anechoic) alignment in practice is rarely ideal, except in extreme circumstances. I generally design max flat MLTL / MLCH alignments for 'net use (for e.g., most [although not all] of the Metronomes) on the understanding that it's purely a baseline & it is for the end user to tailor things to their own requirements via adjusting the damping & Fp.
I put a pad of 1 inch dacron behind the driver twice as high as the driver extending up from the bottom of the driver placement. This helped reduce an echoing sound that must have been a rear reflection. It didn't seem to do much else.Jim Shearer said:
Then I tried the BSC. It is a clear improvement but I'm not settled on it yet. I used the 1mH and 3r9 combination with no zobel. I found the zobel just muted the highs. I liked 3r3 but the highs sounded a little too there and I'm not sure but I think 3r9 is just better. 4r7 was a little muted in the mids, I think.
I'm not sure about 1mH though. I say this because the speaker still sounds shouty under some circumstances but not others which makes me think there is a peak somewhere so I feel the need to measure. If nothing shows up then it must be a break in issue.
I took these to a larger room (30' x 50'). I had them a few feet from the wall to reduce boominess. The max flat alignment is obvious, the cut off almost souns like boom in this room. I tried a few different placements but I only spent an hour or so trying. I'd like to consider Bob Brines proposal here
so....
Would making the standard 3" long port on the 108es' longer be a valid tweak?Scottmoose said:
I also noticed in the larger room that the box seemed to sound hollow. There may have been some room acoustics confusing the matter, not sure but it did sound like pipe resonances. As I said I'm not using much damping yet but most suggest not to. The thing is that I can't notice it in a normal setting at closer listening distances, even at the same elevated volume levels. I might find an improvement if I pack the upper pipe so I should try that.
Bob Brines said:
Average of 8 FE206 (i've got more data but haven't coallated it yet (same with 207))
Fs 46.67
Re 7.01
Qms 5.02
Qes 0.36
Qts 0.33
Vas 62.37
Mms 11.81
Sd 211.24
dB 94.60
Cms 9.88E-07
BL 8.27
dave
Thank you Dave and Bob. Dang, Qts of .33 (vs. factory spec of .18). That's more than a little variance.
rjbond3rd said:
Not necessarily... the variance on the same pair (of FE127eN) between what i measured using FuzzMeasure & what Mark of Mark Audio measured using the same stuff most manufacturers use was of similar order.
T/S are not numbers they are a curve, and what we measure is a point on the curve. More reseacrh needs doing.
dave
I hope the following one is a bit better. 🙂
Simulation with the specs as measured by planet10:
Tuned it a bit higher for less excursion between 50 Hz an 100 Hz.
Simulation with the specs as measured by planet10:
An externally hosted image should be here but it was not working when we last tested it.
Tuned it a bit higher for less excursion between 50 Hz an 100 Hz.
rjbond3rd...
how's the turntable thing working out? (sorry for a bit of a OT comment, all)
As, usual, (by default), Dave's on top of almost most things fullrange. Both Bob's and Scott's points are well made: sim to a point, then let the end user tune to taste... just because something sims well or measures well, doesn't mean it will sound good.
how's the turntable thing working out? (sorry for a bit of a OT comment, all)
As, usual, (by default), Dave's on top of almost most things fullrange. Both Bob's and Scott's points are well made: sim to a point, then let the end user tune to taste... just because something sims well or measures well, doesn't mean it will sound good.
( Hi Stew, my turntable is kaput! But I'm working on a few speaker builds in parallel, may have pix soon... )
I'm going to build a second set of metronomes but these ones need to be rectangular. I want to fold them and install an opposing pair of corner reflectors in the bend. The depth of the cabinet would be constant.
Q. As the driver is not in the middle of the line, would I be best making a 'J' shaped enclosure with the driver centred between the reflectors at the end of the cabinet or should I fold the line in a 'U' shape with the driver in a straight portion of the line.
Q. Would the line still do the 'quadratic' thing?
Q. I want to set the rolloff to look like a lower Q so should I make the line longer or can I just leave it and tune it in other ways?
Q. As the driver is not in the middle of the line, would I be best making a 'J' shaped enclosure with the driver centred between the reflectors at the end of the cabinet or should I fold the line in a 'U' shape with the driver in a straight portion of the line.
Q. Would the line still do the 'quadratic' thing?
Q. I want to set the rolloff to look like a lower Q so should I make the line longer or can I just leave it and tune it in other ways?
well technically, then
it won't really be a metronome, but perhaps more like this:
these work quite well, and are not a particularly difficult build
it won't really be a metronome, but perhaps more like this:
An externally hosted image should be here but it was not working when we last tested it.
these work quite well, and are not a particularly difficult build
Allen,
The line becomes a folded ML-Voigt with a linear taper.
A couple fold possibilities pictured here:
http://www.diyaudio.com/forums/showthread.php?postid=1885581#post1885581
dave
The line becomes a folded ML-Voigt with a linear taper.
A couple fold possibilities pictured here:
http://www.diyaudio.com/forums/showthread.php?postid=1885581#post1885581
dave