col said:Yesterday the wood arrived for my speakers. I had this done at a place called Allboard Distributors. www.allboard.com.au
Basically, I downloaded their order forms filled them in drew a diagram of how I wanted the front baffle to be and faxed it to them. Within an hour they phoned me back. After a bit of a chat (turns out one of their guys in the workshop used to work for Jensen speakers). They gave me a quote for $190.
Below is what I received a week later.
http://pix.minirig.org.au/main.php?g2_itemId=588&g2_page=2
I consider this to be excellent craftsmanship and very good value for money. When it comes to trades people it is hard to beat this country
Looks like I won't be doing too much sanding
col.
I've also used Allboards in the past and found them to be good (and reasonably priced).
Just wondering if they did the rebating for you and the edge routering?
Im also wondering where you found the gold dome nuts for the your rack, as I built the same rack and have been searching for 3/4" dome nuts in Melbourne for ages!
Yes, all the routing and edging was done by Allboards. I live in a small apartment without a shed so can't do work like that.
Brett, I don't think it would cost that much to ship to Sydney. Give them a call.
For nuts and bolts check out http://www.keables.com.au/contacts.htm they are in A'becketts St close to Jaycar.
col.
Brett, I don't think it would cost that much to ship to Sydney. Give them a call.
For nuts and bolts check out http://www.keables.com.au/contacts.htm they are in A'becketts St close to Jaycar.
col.
Speakers are now assembled. Initial tests are very positive testing with various eq'ing using the DEQ2496. Even just using the DEQ2496 auto-eq with room correction gives good results. I'm going to do a bit more work on the waveguides, I have got some foam plugs from Earl on the way. So will have another go at them when they arrive.
some more photos:
http://pix.minirig.org.au/main.php?g2_itemId=588&g2_page=3
col.
some more photos:
http://pix.minirig.org.au/main.php?g2_itemId=588&g2_page=3
col.
col said:
Great photos and interesting project. Note that the 12-inch version (no longer available) is the stock WG on the Emerald Physics CS2 which sounds pretty decent by all standards. Many people have used Bondo or similar material to damp the rear of the thin plastic cone on the PE units.
You might find these mods interesting:
http://cgi.ebay.com/Dayton-Audio-10...39:1|66:2|65:12|240:1318&_trksid=p3286.c0.m14
Very interested in how you are going to attach the foam inside the WG.
The Ebay photos show clearly why I dislike that mounting arrangement. The waveguide is weakest at its smallest point. There is no reinforcement at the throat and there can't be with that type of mounting. My scheme is strongest at the throat.
Col.
I just glue my foam in - whats the problem? Just use a spray adhesive like 3M spray 90 - works fine. You do realize that the waveguide with foam will require a diferent EQ than without. You can't just put the foam in and take it out to compare UNLESS you re-EQ it for the two different cases.
Col.
I just glue my foam in - whats the problem? Just use a spray adhesive like 3M spray 90 - works fine. You do realize that the waveguide with foam will require a diferent EQ than without. You can't just put the foam in and take it out to compare UNLESS you re-EQ it for the two different cases.
I will probably build the back of my waveguides up using car body filler, it's a bit more dense then bondo. The ones in the ebay photos look very rough, I'm hoping for something a bit more refined than that.
I won't be getting any machining done on the throat adapter. The internal diameter is exactly the same size as the internal throat of the B&C DE10-8 compression driver, which was a bit of a fluke. just a little bit of modeling clay to smooth the transition seems fine.
Also, the waveguides in the ebay photos have not been sanded down inside. There are quite a few humps/ripples in the molding that can be smoothed out with a bit of sanding. Once I get the HOM-less foam plugs sanded to size I will glue them in using the spray adhesive Earl mentioned. That will also help to hide the sanding marks.
I'm contemplating taking the waveguides to the car panel shop where I had the speakers painted and getting them spray painted the same colour. Car paint shops have a special thinner that they use when they have to spray paint plastic bumpers so the paint doesn't crack if the plastic flexes.
EQ'ing and re-EQ'ing won't be a problem using the DEQ2496 I can save up to 60 different profiles.
col.
I won't be getting any machining done on the throat adapter. The internal diameter is exactly the same size as the internal throat of the B&C DE10-8 compression driver, which was a bit of a fluke. just a little bit of modeling clay to smooth the transition seems fine.
Also, the waveguides in the ebay photos have not been sanded down inside. There are quite a few humps/ripples in the molding that can be smoothed out with a bit of sanding. Once I get the HOM-less foam plugs sanded to size I will glue them in using the spray adhesive Earl mentioned. That will also help to hide the sanding marks.
I'm contemplating taking the waveguides to the car panel shop where I had the speakers painted and getting them spray painted the same colour. Car paint shops have a special thinner that they use when they have to spray paint plastic bumpers so the paint doesn't crack if the plastic flexes.
EQ'ing and re-EQ'ing won't be a problem using the DEQ2496 I can save up to 60 different profiles.
col.
col said:
The WG will roll off at 6dB/octave starting from 5 - 7kHz and up. If you don't want to use up the dynamic range of the digital equalizer, you can insert a passive shelving hi pass filter to compensate. Try something like 3uf in series with the compression driver. Try resistors from 25 - 100 Ohm in parallel with the cap. You don't have to get perfect response here, since you will adjust with the digital device, but get it within 6dB or so.
Sheldon
tomcat9 said:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=123426
http://www.gedlee.com/downloads/Horn VS waveguide.pdf
..I'm assuming this is what you're referring to.
Hi Sheldon,
Iv'e been trying to avoid using passive components and doing everything in the digital domain with the DEQ2496. I haven't run out of processing power at all. I see your logic though. Someone in another thread mentioned I should have a protection cap too and perhaps even a lpad to reduce hiss. Maybe a minimal amount of passive components to give protection and more range to the DSP is a good compromise. Will have a good think about it.
cheers,
col.
It's an old-school practice to protect compression drivers with a series capacitor on active systems.
However, I have never used these capacitors and I have fed low frequencies to compression drivers by mistake many times. I have never managed to damage a compression driver that way. Damage is unlikely to happen at the power levels that you use when you are checking that everything is hooked up and working properly.
Furthermore, the capacitor adds an extra pole that requires further compensation in the crossover unless a very high value is employed to shift the pole down towards the midbass.
However, I have never used these capacitors and I have fed low frequencies to compression drivers by mistake many times. I have never managed to damage a compression driver that way. Damage is unlikely to happen at the power levels that you use when you are checking that everything is hooked up and working properly.
Furthermore, the capacitor adds an extra pole that requires further compensation in the crossover unless a very high value is employed to shift the pole down towards the midbass.
gedlee said:
OK, we add a cap to simulate a single pole RC high pass filter and remove a pole from the active filter to compensate.Eva said:
or
Add a cap ten times larger than the active filter requires and leave the active filter as was.
Is ten times larger, big enough?
Which alternative is better?
Again personally, I would NOT use a random cap value, I would find the one that makes the smoothest response thus minimizing what needs to be done in the active section. Too large a cap is a waste of money and lowers the protection. Too small a value and you end up have to take out its effect in the active EQ. But there is usually a value that basically flattens the response (assuming constant directivity here) and isn't too large or too small. It's also not a bad idea to put a resistor in parrallel with the Cdriver to smooth its impedance curve as this will help the cap in its job. The loss from this resistor is usually negligable.
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