And the compound angles make getting everything flush a problem too as I recall. I did a spreadsheet back when I looked at this originally to get the cuts correct, and the small difference between square and flush was enough to make a weaker joint.
I'll have to search for that spreadsheet, it would take another week or two of education to replicate it if I had to.
I'll have to search for that spreadsheet, it would take another week or two of education to replicate it if I had to.
Are people really having success using underdamped horn drivers in the Metronome?? (for example the FE126) I can't imagine this 'working' without a notch filter, and even then, fixing peaky speakers with EQ or notch filters often is less than satisfying. They remain underdamped.
I have not built or heard the Met, per se, but IME moderately to under damped drivers tend to work the best in equivalent types. If I had to pick an ideal driver, I'd go for Qts .6 or so, with a highish Qms. Perhaps .4-.5 would be suitable if using tube amplifiers.
I have not built or heard the Met, per se, but IME moderately to under damped drivers tend to work the best in equivalent types. If I had to pick an ideal driver, I'd go for Qts .6 or so, with a highish Qms. Perhaps .4-.5 would be suitable if using tube amplifiers.
IIRC, the angle to cut the compound angles correctly is something like ~1/2 a degree. As someone pointed out, that's well within the margin of error on most saws.
If working with pre-veneered stock, it'd be prudent to cut to a little sharper angle (1 degree?) to get a tight outer edge joint. (assuming you have some sort of pro $$ super accurate saw)
BTW, veneer edge tape is available for just about every common type of hardwood.
If working with pre-veneered stock, it'd be prudent to cut to a little sharper angle (1 degree?) to get a tight outer edge joint. (assuming you have some sort of pro $$ super accurate saw)
BTW, veneer edge tape is available for just about every common type of hardwood.
I was looking through this thread and I guess I had pointed that out at one point. It is a really tiny amount.
I know there is veneer tape, but it is the stain matching that will be hard. This flooring is pre-stained. I'll have to see what I used on the molding for the floor. It was close.
I've had a number of non-starts on this project.
I know there is veneer tape, but it is the stain matching that will be hard. This flooring is pre-stained. I'll have to see what I used on the molding for the floor. It was close.
I've had a number of non-starts on this project.
I believe you mean 'over-damped' [<0.5 Qts], so yes, BSC or similar will normally be required to get it tonally flat to anywhere near Fs.
If one looks at some vintage drivers and their recommended cab alignments we see that the ‘effective’ Qts [Qts + any series resistance = Qts’] tends to be around 0.7, which in turns defines a max flat alignment, so this is my target Qts’, though I've had equally good results with as high as 1.0 when Vas is high also and there's no cab size restriction.
A ~0.403 Qts’ gets you a T/S max flat alignment where Fb = Fs, Vb = Vas, though 1/4 WL pipe loading normally allows a bit lower tuning if desired and assuming there's enough extra net Vb [> Vas] to support it. Otherwise, just like with a reflex, a Qts’ > 0.5 results in a > Vas net Vb and < Fs tuning.
GM
I checked the dimensions in the tables vs. the dimensions of my flooring. For a 126E driver I see 48" high and a 7.75" max width. My floor boards are 95 3/8" long and 7.875" wide. So one board will give me front and back, but I'm a little bit short, especially if I want a solid front. It also doesn't leave length for the bottom stand. Ah, but this wood has click lock joints, so I could extend it, no problem then. And width is nearly perfect, I'll adjust the overall area of the bottom and compensate on the sides.
The flooring is 5/8" thick, so OK for these too.
When I did the floors I was learning as I went. They came out great, it really is pretty easy. The hardest part is I'm in an old house and the corners weren't square so I had to cut long tapers. And this is exactly what these speakers call for...
One question. Do you line these boxes with damping material?
The flooring is 5/8" thick, so OK for these too.
When I did the floors I was learning as I went. They came out great, it really is pretty easy. The hardest part is I'm in an old house and the corners weren't square so I had to cut long tapers. And this is exactly what these speakers call for...
One question. Do you line these boxes with damping material?
I haven't taken the time to check its taper, but it takes a > ~12 deg included angle for 'slap echo’ to rapidly decay, so best to assume that at least some wadding is required at the extreme top and lining one side and back in the immediate driver area.
After that, it becomes too personal a preference IME and the amounts recommended in MJK's software to make the super smooth response folks tend to 'demand' has many times proven to 'suck the life' out of 'FR' drivers, especially the 'delicate' ones such as the Jordans [at least the older ones].
GM
After that, it becomes too personal a preference IME and the amounts recommended in MJK's software to make the super smooth response folks tend to 'demand' has many times proven to 'suck the life' out of 'FR' drivers, especially the 'delicate' ones such as the Jordans [at least the older ones].
GM
Zacster,
In all the Mets I've built, I line only the back--from top to bottom. More lining will over damp as GM says & suck the life out of the speaker.
I will be interested to hear how your project goes. Having built Mets with a number of different Fostex drivers, the FE126e isn't one I would use.
Cheers, Jim
In all the Mets I've built, I line only the back--from top to bottom. More lining will over damp as GM says & suck the life out of the speaker.
I will be interested to hear how your project goes. Having built Mets with a number of different Fostex drivers, the FE126e isn't one I would use.
Cheers, Jim
I'm only using the 126E because that's what I have. This is going to be a virtually no cost build. I was also going to try the Radio Shack drivers that I have, but I've searched for the specs on them and was never able to find any. They are NOT the ones that everyone uses, but they still sounded OK in my cardboard boxes. I was thinking that I'd make the bottom replaceable so I could adjust the length by trial and error to see if I could tune the sound.
A funny Comparison of 2 full rangers
This thread has the model number, and you had even replied to it back then. 40-1041. I had the same plan then too, to build them from the flooring. And I still haven't finished the closet!
In the three intervening years I haven't done anything related to audio or video. I had bought a plasma TV, and an Oppo blu-ray in 2011, and put it "temporarily" on a glass table until I could find a suitable cabinet that could also accommodate my tube amp, pre-amp and large center channel speaker. Well, the center channel is still sitting in my hallway, my subwoofer hasn't been plugged in since, I use the rear speakers occasionally (Game of Thrones comes to mind). I listen to Pandora with its mediocre sound quality more than anything else. I guess I just had other priorities.
This thread has the model number, and you had even replied to it back then. 40-1041. I had the same plan then too, to build them from the flooring. And I still haven't finished the closet!
In the three intervening years I haven't done anything related to audio or video. I had bought a plasma TV, and an Oppo blu-ray in 2011, and put it "temporarily" on a glass table until I could find a suitable cabinet that could also accommodate my tube amp, pre-amp and large center channel speaker. Well, the center channel is still sitting in my hallway, my subwoofer hasn't been plugged in since, I use the rear speakers occasionally (Game of Thrones comes to mind). I listen to Pandora with its mediocre sound quality more than anything else. I guess I just had other priorities.
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I think I remember the 40-1041. It was IIRC sort of a less fancy 40-1354, with a smaller magnet. Did it maybe have a plastic whizzer?
I'd expect that they have moderately high Qts, and IMO are more suited to a Metronome than the FE126, but again, impossible to make an ideal box without specs. Anyhow, you would most likely have to measure them yourself, unless someone has one in their stash, and is willing to do it for you. Why not just make a fancier Metronome for them, since you like the sound? The less than perfectly resolved aspect of the bargain drivers will make things like Pandora more listenable.
The FE126 should go in a back horn, a front horn, or perhaps a scaled Karlsonator.
I'd expect that they have moderately high Qts, and IMO are more suited to a Metronome than the FE126, but again, impossible to make an ideal box without specs. Anyhow, you would most likely have to measure them yourself, unless someone has one in their stash, and is willing to do it for you. Why not just make a fancier Metronome for them, since you like the sound? The less than perfectly resolved aspect of the bargain drivers will make things like Pandora more listenable.
The FE126 should go in a back horn, a front horn, or perhaps a scaled Karlsonator.
It's rolling the dice to simply guess, and in fact it will take much less time to measure the speakers than rebuilding an enclosure that doesn't sound good. That caveat out of the way, I'd probably go for the smaller one for the FE167 in those tables. Make some sort of provision for experimenting with different ports, as the stock tuning is unlikely to be right.
Sometimes it's good to just do, and figure out what you did later...
Measuring T/S parameters is pretty easy. You need a multimeter, a resistor, and a computer with a soundcard to use as a signal generator. Oh, and a tupperware bowl or some enclosure of known volume for Vas. There are tutorials on the web. Or just buy the USB dongle device from partsexpress and click a couple buttons.
Sometimes it's good to just do, and figure out what you did later...
Measuring T/S parameters is pretty easy. You need a multimeter, a resistor, and a computer with a soundcard to use as a signal generator. Oh, and a tupperware bowl or some enclosure of known volume for Vas. There are tutorials on the web. Or just buy the USB dongle device from partsexpress and click a couple buttons.
![40-1041 specs [GM SWAG].gif](/community/data/attachments/393/393305-24a8ea8f64bde4477d51db7e97443df1.jpg)
I put the RS drivers back into my cardboard Mets, and braced the boxes better than they were before by wrapping tape tight around them.
On some tracks they sounded fantastic, in particular jazz vocals, with some nice bass. On other tracks, you could hear immediately that something was completely missing. It seems that transient bass, like kick drums, doesn't come through, nor does electric bass, but acoustic bass does. This could be a function of my box just absorbing it, it is cardboard after all, but it lets an extended bass line through? Or it could just be the wrong dimension?
I looked at how to take measurements, and I probably have enough on-hand to do it. I have an SPL meter and a computer, lots of resistors laying around and a DVM.
What is this?
On some tracks they sounded fantastic, in particular jazz vocals, with some nice bass. On other tracks, you could hear immediately that something was completely missing. It seems that transient bass, like kick drums, doesn't come through, nor does electric bass, but acoustic bass does. This could be a function of my box just absorbing it, it is cardboard after all, but it lets an extended bass line through? Or it could just be the wrong dimension?
I looked at how to take measurements, and I probably have enough on-hand to do it. I have an SPL meter and a computer, lots of resistors laying around and a DVM.
What is this?
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