Omegaspeedy Posted June 18, 2010 Posted June 18, 2010 This is a follow on from my last speakers I built and thought I would share some pic's. After developing the last ones to the point they had tweeter holes in the top (failed experiment) and a modified rear port, I was so happy with the results that I started the build again this time adding a few improvements. The changes: built in binding posts. Side panel grain horizontal (SF style) Redesign of rear port. (same size as last but implemented better. Slightly larger Cab to suit the 40mm baffle. Flush drivers, further distancing cone from rear port (greater low end extension). Less reflective beveled internal brace. Reconfiguration of panels to allow a more pleasing to the eye front baffle. Shorter signal path of the filter cough cough. A lot more time spent on the surface finish quality. And most importantly all panels machined to .25mm for consistency of pair matching. Can't wait to get them running but don't want to hurry them.
Owen Y Posted June 18, 2010 Posted June 18, 2010 James, you are becoming a certifiable craftsman! Looking forward to the auditioning report.
Omegaspeedy Posted June 18, 2010 Author Posted June 18, 2010 Cheers Owen, i'll keep you posted. Have you been building lately? Field coils maybe:)
Owen Y Posted June 18, 2010 Posted June 18, 2010 Yup, a couple of sm PSUs for the FCoil drivers. Simple really, but of course they had to have wood bases & I needed to have a couple of trannies wound.
Omegaspeedy Posted June 18, 2010 Author Posted June 18, 2010 Excellent! hopefully you will show when up and running. They are very appealing those Field coil drivers. Looking forward to the day I can get my hands on some. Not many are affordable yet.
monoclepop Posted June 18, 2010 Posted June 18, 2010 Wow, those look fantastic! Sorry for asking silly questions, but I'm interested in what you've made them out of - that aint no MDF that I've ever seen. What did you use (inside and out), and how did you finish it?
Omegaspeedy Posted June 18, 2010 Author Posted June 18, 2010 Hi Dusty, its this stuff finished with Danish oil. The photo's show four coats but I'm aiming for eight. I lightly sand between coats with 800p sand paper. http://www.trademe.co.nz/Building-renovation/Building-supplies/Panels-boards/Other/auction-297156921.htm It's lovely to work with and when Dynamat is applied inside it is very inert. James.
tigi Posted June 18, 2010 Posted June 18, 2010 bloody h*ll that timber looks really smart! looks like a satin finish? Good choice IMO. don't go too shiny. I guess that edge laminated timber will be a lot stiffer and more uniform than a single timber slab. well done indeed!
Omegaspeedy Posted June 21, 2010 Author Posted June 21, 2010 More photo's of newly layed out filter (Mundorf M-resist .82 & Mundorf Air Cored Copper Foil Coils 1mH in parallel) and semi-finished cab. Filter plate sitting on compressed foam, and inductor sitting on cotton pads. Yet to put bitumen damping on the bottom of filter mount. Four more coats of Danish oil to go. The Stands are half way made out of the same wood. The sound is similar to the last but bass is not as tight and the sound a little constrained. Six Cardas silver solders were required per filter during the reconfiguration and you can hear them!! A good 200-300 hours is required as per the last time (Don't kid yourself that burn in of solder is in the head! if you do you might as well buy a big Sanyo from 'The big red' and be happy:)).
Ernie1553552694 Posted June 21, 2010 Posted June 21, 2010 Nice work James. Looking forward to the reports after burn-in.
Guest Guest Posted June 21, 2010 Posted June 21, 2010 Wow. You've been a busy boy! Those look beautiful, James, and as usual I bet they'll sound better than you give yourself credit for. BTW, what is that on your rack, second shelf down? :cool:
little blue penguin Posted June 21, 2010 Posted June 21, 2010 Hi James, I'm so impressed by your workmanship, but your comments on the solder have me interested. How are you soldering the crossovers and other connections. Ideally with point to point wiring you should be ensuring a good mechanical connection first, and then soldering only to seal against oxidation. Is that what you're doing? Now, how much how a pair of frugalhorn cabinets with full height rear deflectors;)
Antipodes1553552706 Posted June 21, 2010 Posted June 21, 2010 cloth_ears;126039 wrote: Hi James, I'm so impressed by your workmanship, but your comments on the solder have me interested. How are you soldering the crossovers and other connections. Ideally with point to point wiring you should be ensuring a good mechanical connection first, and then soldering only to seal against oxidation. Is that what you're doing? Now, how much how a pair of frugalhorn cabinets with full height rear deflectors;) The presence of the solder enables eddy currents, that diminish with burn in, even if a solid physical connection is made first.
Omegaspeedy Posted June 21, 2010 Author Posted June 21, 2010 cloth_ears;126039 wrote: Hi James, I'm so impressed by your workmanship, but your comments on the solder have me interested. How are you soldering the crossovers and other connections. Ideally with point to point wiring you should be ensuring a good mechanical connection first, and then soldering only to seal against oxidation. Is that what you're doing? Now, how much how a pair of frugalhorn cabinets with full height rear deflectors;) Hi Cloth_ears, I use a technique to minimize the amount of solder required. I don't know if it is used by anyone else. I thought it up myself. It involves rolling a segment of fine copper (cut from the tongue of a foil wound inductor) around the bare wire approx two revolutions and soldering the joint. Soler runs in the joint by capillary action and a small amount leaks onto the bare wire to hold it in place. I then solder this to the leg of the resistor. The aim I'm trying to achieve is not saturating the bare wire. This would be required if you were to try to solder it (bare wire) alone to the resistor leg. It does take a bit longer and is fiddly but to do think the results are worth it. The result is way less solder involved ie 3mm's instead of 6 o 7mm required). All four joints are treated this way. 1) Binding to 2) resistor, 3) resistor to speaker +, Speaker - to 4) Binding post. Cheers James.
Omegaspeedy Posted June 21, 2010 Author Posted June 21, 2010 sirAndy;126037 wrote: Wow. You've been a busy boy! Those look beautiful, James, and as usual I bet they'll sound better than you give yourself credit for. BTW, what is that on your rack, second shelf down? :cool: Hi Andrew, cheers for the comments, when run in you'll have to swing on by for a good session! The item on the second shelf down is a box set of Pink Floyd 'Shine on' with book and 8 CD's that a friend lent me. Enjoying it right now BTW:)
ilikecrumpets Posted June 21, 2010 Posted June 21, 2010 Fabulous work James, looks like you have talent in abundance! And it looks like a very nice listening room as well...
Shane Hanify Posted June 21, 2010 Posted June 21, 2010 Gidday James, what gorgeous cabs. I don't care what the sonic benefits are - I'd rather real timber over laminated MDF any day. Cheers, Shane.
Omegaspeedy Posted June 21, 2010 Author Posted June 21, 2010 Low Orbit;126062 wrote: Gidday James, what gorgeous cabs. I don't care what the sonic benefits are - I'd rather real timber over laminated MDF any day. Cheers, Shane. Cheers Shane. Real wood does look very good and when I chose this product, one thing I liked about it was the 50mm finger jointed panels it's made from. When you have multiple panels to make one, the consistency (average density) becomes very close between the two cabinets. The main complaint of real wood cabinets is the consistency between the cabs because of grain differences. I don't think that applies here. Another surprising characteristic of this wood is how inert it is when a strip of dyamat is applied inside. They don't have the big over warm sound that they look like they should have. Cheers James.
Owen Y Posted June 21, 2010 Posted June 21, 2010 The principle of 'laminating' small pcs of wood together to make a bigger panel, also tends to result in a more stable panel - less bowing or cupping.
Electra Posted June 22, 2010 Posted June 22, 2010 I have seen speakers made of this material before - but internally was a box made of 18mm MDF or ply, this was "laminated" ( for lack of a better word than "glued" ) to the real timber outer of the cabinet. Very, very heavy, and the guy who built them showed me one of his prototype cabinets which he didn't like with a rear tire of a 6tonne tractor parked on it. Without breaking it. Just whether this effort is valid, I don't know.
Omegaspeedy Posted June 22, 2010 Author Posted June 22, 2010 too_tall;126084 wrote: I have seen speakers made of this material before - but internally was a box made of 18mm MDF or ply, this was "laminated" ( for lack of a better word than "glued" ) to the real timber outer of the cabinet. Very, very heavy, and the guy who built them showed me one of his prototype cabinets which he didn't like with a rear tire of a 6tonne tractor parked on it. Without breaking it. Just whether this effort is valid, I don't know. They would have been super heavy TT. Owen Y taught me a while back about the importance of damping to the right level and not to over damp as it kills the micro-dynamics. (Speaker stands and lead shot Owen?). I also found when I added another panel of 25mm MDF to the sides of my BLH horn speakers that a little bit of the life blood of the music vanished. These cabs I've tried to damp only as much as needed (minimal) to remove colouration to a point. I didn't want to kill the heart and soul of the music, especially full range drivers. Yes I know I'm running a circuit but the benefits way out way the negatives. BBC and SF found this out and apply this concept as standard to their designs. The way I see it now, is a dead cabinet is a dead cabinet:) Good vibrations are desirable.
Electra Posted June 22, 2010 Posted June 22, 2010 yes, I can believe that. while talking of box speakers at least. OB/TM/electrostatics live by different rules I would imagine. I guess it can also depend on the drivers being installed in the cabinet - super powerful drivers with high powered amplifiers can put a lot more stress on a cabinet than low powered drivers with a small amplifier. I never heard the cabinets I mentioned running with a decent setup, they were using some 6.5" ultra high excursion Digital Designs woofers, scanspeak 4" mids and ring tweeter - with active amplification. Drivers which could make for some excellent quality reproduction if done right. However when I heard them, the crossover was a PA active crossover as he was fiddling around getting the best crossover points. A far cry from the active crossover he was planning on building.
Omegaspeedy Posted June 22, 2010 Author Posted June 22, 2010 too_tall;126086 wrote: yes, I can believe that. while talking of box speakers at least. OB/TM/electrostatics live by different rules I would imagine. I guess it can also depend on the drivers being installed in the cabinet - super powerful drivers with high powered amplifiers can put a lot more stress on a cabinet than low powered drivers with a small amplifier. I never heard the cabinets I mentioned running with a decent setup, they were using some 6.5" ultra high excursion Digital Designs woofers, scanspeak 4" mids and ring tweeter - with active amplification. Drivers which could make for some excellent quality reproduction if done right. However when I heard them, the crossover was a PA active crossover as he was fiddling around getting the best crossover points. A far cry from the active crossover he was planning on building. Yes I think your right TT that hi quality (Hi Definition) drivers in a dead box with a well designed high quality cross-over will give superb results when being run by a compatible high quality amp. OB's may have more in common with good vibrations but stats I'm not sure. I put my Visatons on a ply baffle and latter on a HDF (High density fibre) baffle. The ply was exceptional except the lack of bass. The HDF was a better designed baffle for bass output with respect to size and shape but the presentation was lifeless. I put it down to favorable vibrations on the ply baffle.
Owen Y Posted June 22, 2010 Posted June 22, 2010 Incidentally, what is the filter cct doing, James? Bandlimiting the bott end a bit to make life easier on the amp?
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