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Old 5th January 2013, 02:14 PM   #1021
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Quote:
Originally Posted by xrk971 View Post
I finally had some time to lay out my homage to the FH3 in foam core. I scaled it to 30 in tall and internal cross sections scaled relative to TC9FD driver Sd. This gives cabinet dimensions of 4.5 in wide x 5.0 in deep (internal dims). Terminus height is 1.33 in and I plan to flare the back horn out in a smooth expansion to 12 in wide. This serves to provide built in stabilization feet and gives horn more lateral expansion. It increases final horn's expansion ratio by almost 3x, hopefully this will boost the weak bass from the tiny 3.5 in Vifa. As usual, cutting or scoring the wings on the horn allows a nice smooth compound curve that looks great and will be quite rigid once glued. I just have to find a bit of time to glue now. I sim'd this in HR and got a reasonable frequency response curve showing the low bass peak at 73 Hz. There is a big dip around 125 Hz but that should be filled in by Vifa's natural peak there as fs is 125 Hz.
xrk971,

Anxious to hear of your results with this. I've looked at that many times. It's nice to be able to try out ideas quickly in foam!
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Old 5th January 2013, 02:34 PM   #1022
xrk971 is offline xrk971  United States
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Surface Tension,
Yes, it is very quick. The layout on the first one takes longer but with a template formed from first the second should go even faster. It took me 2 hours to carefully layout, develop the curved wings concept and test it, and do final cuts. The second unit shouldn't take more than 30 minutes to cut as they are all mostly long straights. If I can get the bass to go down to 73 Hz with the Vifa, that will be an accomplishment. We will see... this is my first build where i simulated it first to make sure it isn't crazy.
Are you still listening to your cornu's?
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Old 5th January 2013, 08:19 PM   #1023
xrk971 is offline xrk971  United States
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Default Update on Frugel Foam 3 progress

Ok, I managed to glue together everything but the base, which is last due to curves. Everything was done with hot glue except for second side panel which was done with pva. I threw in some bracing where needed. I used open cell foam around driver and pillow stuffing elsewhere. The foam let me make a radiused terminus choke point. This is my first foam core speaker with real binding postts. Now just waiting for glue to dry....

It's interesting to note that this is more difficult to build than the cornu since the corners and edges need to be even and square to look good and make a good seal.
Attached Images
File Type: jpg Foam-FH3-build-0125137105.jpg (104.5 KB, 442 views)
File Type: jpg Foam-FH3-build-02866336856.jpg (101.1 KB, 437 views)
File Type: jpg Foam-FH3-build-05-960557547.jpg (119.5 KB, 432 views)
File Type: jpg Foam-FH3-build-04670431727.jpg (147.9 KB, 408 views)

Last edited by xrk971; 5th January 2013 at 08:26 PM.
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Old 5th January 2013, 09:37 PM   #1024
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By 'ek! Be interesting to hear your impressions.
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Old 5th January 2013, 09:46 PM   #1025
xrk971 is offline xrk971  United States
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Thanks Scottmoose. If you have nothing to do would you mind running an MJK sim with 30 in tall cabinet with 4.5 in width and 5 in deep and 1.33 in wide terminus? The driver is TC9FD. Probably not the best driver but it's what I have handy. Thanks in advance.
Regards,
Xrk971
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Old 5th January 2013, 11:30 PM   #1026
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Hey X,

I too am very interested. I hope Scott can find some free time, we know he's a busy guy. Is that enough bracing to eliminate panel movement?

Like you I am waiting for glue to dry so I guess we find out tomorrow.
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Old 5th January 2013, 11:38 PM   #1027
xrk971 is offline xrk971  United States
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Cal,
I hope it's enough bracing, there is more than picture shows as that was interim. Too late now as she's all buttoned up. We will hear tomorrow.
That whole "I will hang out with my buds at the strip club" made me lol, but wouldn't fly at my house You got to love how they put up with our hobby.

Good luck with the new cornu first sound tomorrow!

Last edited by xrk971; 5th January 2013 at 11:40 PM.
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Old 5th January 2013, 11:51 PM   #1028
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Originally Posted by xrk971 View Post
That whole "I will hang out with my buds at the strip club" made me lol, but wouldn't fly at my house
Mine either, that's why I use it. She knows damn well those girls could be my daughter and also knows how long ago I went to one of those places. She appreciates the sentiment and that's why speakers are soooo good all of a sudden.
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You got to love how they put up with our hobby.
Hmm... seems we still need some form of ammunition.
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Good luck with the new cornu first sound tomorrow!
Thanks, can't wait myself. I just hate when it interrupts my sleep though. I hope your mini FH3's have the same effect.
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Old 6th January 2013, 03:44 AM   #1029
xrk971 is offline xrk971  United States
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Originally Posted by xrk971 View Post
Ok, I managed to glue together everything but the base, which is last due to curves. Everything was done with hot glue except for second side panel which was done with pva. I threw in some bracing where needed. I used open cell foam around driver and pillow stuffing elsewhere. The foam let me make a radiused terminus choke point. This is my first foam core speaker with real binding postts. Now just waiting for glue to dry....

It's interesting to note that this is more difficult to build than the cornu since the corners and edges need to be even and square to look good and make a good seal.
Update: finished gluing the Frugel Foam cabinet. I really like the shape and how it turned out with the flared horn in the back. Still need to cut out hole for driver and mount driver with screws and connect wires. The design is very slim tall and elegant. The flared horn is really needed otherwise additional outrigger feet would have been required. Looking forward to seeing them in action tomorrow.
Attached Images
File Type: jpg Foam-FH3-build-0825137105.jpg (134.2 KB, 368 views)
File Type: jpg Foam-FH3-build-09866336856.jpg (130.0 KB, 176 views)
File Type: jpg Foam-FH3-build-11-960557547.jpg (126.3 KB, 174 views)
File Type: jpg Foam-FH3-build-12670431727.jpg (126.9 KB, 150 views)
File Type: jpg Foam-FH3-build-101648466299.jpg (99.6 KB, 153 views)

Last edited by xrk971; 6th January 2013 at 03:48 AM.
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Old 6th January 2013, 07:14 AM   #1030
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Wow xrk you're like a master foam sculptor. This thread is really throwing me for a loop. I mean foam cabinets and they actually sound good? Yea, I don't know nothing about audio...
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