Ok, I am going to build the triangle rear baffles/reflection for behind my speakers. I would like to include a driver to reach some of the lower freq. Does anyone have the dimensions for ones that they are using? Can I put the driver on the front two angled sides (using two drivers) or should I put it on the back facing the wall/corner? Also, could I down fire it instead? All suggestions would be great... Thanks Folks.
attached as built sketch for the pair in above photo.
intended as easy build, with simple clean lines from the front, which is why the single driver (SDX7) was rear mounted, and amp external
yes - in metric
That was quick - note on the drawings that the SDX7 enclosure is sealed. As long as the driver of your choice is comfortable in a smallish sealed application you could mount them (multiples if you like) where ever they fit, but keep in mind that boundary loading directly into the floor would require at least a few inches of clearance.
With the 90` equilateral triangle shape (chosen for ease of build), the back (hypotenuse) is the widest panel and you can see that it's still a tight fit for magnet to clear.
Two other thoughts - IMHO, it's at least as important to use plywood vs MDF in a small woofer such as this, and bracing is imperative.
And so we could call it a stealthWoofer...
and so that we would get maximum room loading to push the response downward.
downward firingwould be fine, but when you look at the size of the triangle you aren't going to get much woofer mounted there -- i haver some nice looking Peerless 4" i'm trying.
dave
damping materials needed
Hi everybody
I'm about to order the parts for my mk3 build. Question is, how much of the damping material do I need? I was thinking of ordering 2 sheets of this stuff:
Sonic Barrier 1/2" Acoustic Foam w/PSA 18" x 24" 260-520
And a bag of this:
Acousta-Stuf Polyfill 1 lb. Bag 260-317
Is that enough / too much ? The driver I'm planning on using is the chr-70 g3.
How do you glue that stuff down, does regular multipurpose glue do the trick?
Thanks,
Christian
ps: where do you usually route the cables? Do you just clamp them to the inside of the side panels?
Hi everybody
I'm about to order the parts for my mk3 build. Question is, how much of the damping material do I need? I was thinking of ordering 2 sheets of this stuff:
Sonic Barrier 1/2" Acoustic Foam w/PSA 18" x 24" 260-520
And a bag of this:
Acousta-Stuf Polyfill 1 lb. Bag 260-317
Is that enough / too much ? The driver I'm planning on using is the chr-70 g3.
How do you glue that stuff down, does regular multipurpose glue do the trick?
Thanks,
Christian
ps: where do you usually route the cables? Do you just clamp them to the inside of the side panels?
I prefer the 1/2" felted denim Ultratouch insulation as sold in small quantities by Bob Reimer at CSS
Creative Sound - Product Details
The FH3 full documentation has the diagrams for layout and quantities required.
If cut accurately, it will almost friction fit, but a little standard white (Weldbond etc) wood glue is more than enough.
The loose fibre fill in the closed end of taper ( i.e. behind the vertical divider) is the same for all drivers, but the amount of fill required between the driver and choke point will vary from system to system and requires experimentation. Be sure drivers are fully broken in according to Mark's guidelines, and since the section below driver is an expanding taper, it's a good idea to staple or hot glue a retaining mesh or wires to keep fill in place.
Several builders have fabricated with a removable top to allow access to the front taper section for adjusting fill levels during the fine tuning phase - then fill screw holes and complete the finishing when done. I wish I hadda thought of that.
Input terminals can go anywhere you like - I use a cheap round input cup with 5-way binding posts for banana plugs, and mount about 4" down from the top on the rear slanted panel. This keeps the internal wiring as short as possible - it's easily dressed over the top of internal divider and held in place by the damping fill.
I'm not a big fan of the former -- i was given a wholebunch of it, haven't found a use for it, and haven't been able to give it away.
The UltrTouch that chris mentions is trally good (i just bought another 800 ft^2),
Our FH3 flat-paks (with CHR) ship with 2 30g baggies of acoustastuff for the end taper, and 2 40g bags for under the driver (not all necessrily needed). The 1st round shipped with miraflex, but that is unobtainium now.
So 30x2 + 40x2 ~ 1/3 ib of Acoustastiff (Madisound sells in whatever quantity you need, but it never hurts to have a bit extra kicking around)
dave
As Dave has mentioned, skip the foam. It's only purpose, IMHO, is to allow an otherwise nice sounding speaker to sound worse. "Sonic Barrier" is certainly an appropriate name.
I could have had a bunch of that foam myself (rolls of it), but I knew why it was being given away, so I wisely turned it down.
Best Regards,
TerryO
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Quick question.
I've built the Frugel 3 with Alpair 7.3 drivers.
The bass is good; very musical but I'm considering adding a sub for a bit more impact. Since the sub will have a built in crossover, I figured i might as well add a high pass filter to the 7's to help ease the work they're doing on the lower end. What would be the best way to do this, I have been considering a single capacitor. Also what frequency would guys recommend?
I also like the idea of the baffles with helper woofers, but at the moment I don't have the space for them.
While we're at it, I'm also looking for ideas for a 2 way, utilizing a pair of Fostex Fe126n's I have and some type of woofer.
I've built the Frugel 3 with Alpair 7.3 drivers.
The bass is good; very musical but I'm considering adding a sub for a bit more impact. Since the sub will have a built in crossover, I figured i might as well add a high pass filter to the 7's to help ease the work they're doing on the lower end. What would be the best way to do this, I have been considering a single capacitor. Also what frequency would guys recommend?
I also like the idea of the baffles with helper woofers, but at the moment I don't have the space for them.
While we're at it, I'm also looking for ideas for a 2 way, utilizing a pair of Fostex Fe126n's I have and some type of woofer.
For the A7.3 i would suggest a single capacitor in front of your power amplifier... trying to do it passively at speaker level with a monster cap is fraught with problems, it will very likely subtract way more than any gain. Besides the huge sizes required (meaning elcos or big bucks pr both), the impedance at the low end is far from flat.
On ours i am just rolling off the woofers and letting the FH3 run wide open. At some point i'll try adding a HP on the sats (but 1st i need a buffer on the woofer out of my pre)
Small sealed for FE126 6 a suitable pair of midwoofers should work well. Will need to be bi-amped.
dave
On ours i am just rolling off the woofers and letting the FH3 run wide open. At some point i'll try adding a HP on the sats (but 1st i need a buffer on the woofer out of my pre)
Small sealed for FE126 6 a suitable pair of midwoofers should work well. Will need to be bi-amped.
dave
OK, it's a bit off topic, but I have a set of Tannoy NFM 8 speakers and am looking for solutions to making these speakers sing. I'd appreciate your thoughts on using these drivers with this design.
While we're on off topic subjects, I just acquired a set of Altec 604E's (raw speakers) and am looking for an interesting horn design for them. Again, input is appreciated.
While we're on off topic subjects, I just acquired a set of Altec 604E's (raw speakers) and am looking for an interesting horn design for them. Again, input is appreciated.
Aren't those 8" drivers? About the largest you can fit into FH3s are 5" drivers. Thes eare the plastic cone units that came in one of the Tannoy Dimension as well? One would need some T/S before starting. If they are the same drivers, the drivers themselves could use some work.
I don't know of any horns (don't know how suited they would be to horns, and if they were, the horn would be HUGE), but Scott has a nice ML-TL for those (at least the GPA version).
dave
Yes, the Tannoy's are 8" drivers, I've had them for about 25 years in their original boxes (NFM 8 ) which were designed for studio near field monitoring. They are great in their own way but need a different enclosure for room listening. I was hoping someone on this forum would point me in an interesting direction.