Well, as some of you may have remembered, I started a thread about building a 604 and we went back and forth regarding which driver to get, etc etc. Here is how it started:
http://www.diyaudio.com/forums/mult...non-vintage-altec-604-jenzen-illuminator.html
And the final plans were done here:
Ended up using Marine Ply 1" all around and 2" for the front.
A view of the raw cab before staining and spray lacquer:
Picture of the cab with the carpenter who built it as reference to the size of this thing:
Closeup picture of the rounded edging of the openings and the corners:
Unfortunately due to a mishap in shipping, one of the driver was damaged and now the wait continues before I get a replacement driver and the crossovers..... Will keep everyone posted.
http://www.diyaudio.com/forums/mult...non-vintage-altec-604-jenzen-illuminator.html
And the final plans were done here:
An externally hosted image should be here but it was not working when we last tested it.
Ended up using Marine Ply 1" all around and 2" for the front.
An externally hosted image should be here but it was not working when we last tested it.
A view of the raw cab before staining and spray lacquer:
An externally hosted image should be here but it was not working when we last tested it.
Picture of the cab with the carpenter who built it as reference to the size of this thing:
An externally hosted image should be here but it was not working when we last tested it.
Closeup picture of the rounded edging of the openings and the corners:
An externally hosted image should be here but it was not working when we last tested it.
Unfortunately due to a mishap in shipping, one of the driver was damaged and now the wait continues before I get a replacement driver and the crossovers..... Will keep everyone posted.
I don't think there is a set width that is optimal, due to space constraints we built our cabinets deep and tall to get sufficient internal volumn.
What is the green material you have used? How do you find the resonance of your cabinet as it appears you only used 1" wood panels all around?
25-30" pushes baffle step loss low enough [~122-100 Hz F6] to obviate the need for compensation in most HIFI/HT apps and why all the large Altec cabs fall in this range AFAIK.
GM
Heavy rubber carpet underlay.
Subsequent cabs I've added a lot more cross-bracing. Each of the panels on this version had heavy battens added.
Congratulation...Very nicely built cabinet.
Another suggestion is to use thick felt. I've good success using felt on the 416 loaded Onken and Altec 620A cabinet design.
Hunt it down in shops doing car cushion...Got mine at J.B.
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Yep, my current dampening material is two inch thick wool/fibre. See samples.
Attachments
Well, it was a fun adventure building this hulk of a machine, but I think overall it was a great experience. I wish I had more time to enjoy it but alas, life is such... Anyways, here are some pictures of what happened....
The inside of the box, being fitted. All joints are siliconed, and there is enough bracing and support in there to hold up a car:
Here is what they eventually looked like set into their intended surroundings. The veneers were stained to match the existing cabinetry:
Picture of a single speaker:
Closeup of the driver and bass port:
Closeup of the GPA driver with rounded edges of the cab:
Details rarely seen of the connector pins behind:
So, in short it was fun. There were a few hiccups along the way, GPA was great to work with, some patience is indeed required maybe due to age and cultural differences, but eventually everything worked out.
In regards to the sound, well whatever I write will probably not hold much weight but here goes anyways. The highs from the horn is incredible, I originally thought I would need a super tweeter to go with this, but now I don't think I'll need one. The lows are sufficient for what I listen to. The cabinet is around 300ltrs and maybe going up to 400 may change my mind, but we'll leave that to the next build. Overall I am happy with the results which is what matters most, it is much much better than what it replaced, I will have to build a new amp to fully utilise the speaker, the KT-88 that drives it is just too loud and harsh and moving down to a 2A3 will be the next step.
Thank you all once again for all the advise and help, I couldn't have done it without your help especially KF and GM. Until the next one.....
The inside of the box, being fitted. All joints are siliconed, and there is enough bracing and support in there to hold up a car:
An externally hosted image should be here but it was not working when we last tested it.
Here is what they eventually looked like set into their intended surroundings. The veneers were stained to match the existing cabinetry:
An externally hosted image should be here but it was not working when we last tested it.
Picture of a single speaker:
An externally hosted image should be here but it was not working when we last tested it.
Closeup of the driver and bass port:
An externally hosted image should be here but it was not working when we last tested it.
Closeup of the GPA driver with rounded edges of the cab:
An externally hosted image should be here but it was not working when we last tested it.
Details rarely seen of the connector pins behind:
An externally hosted image should be here but it was not working when we last tested it.
So, in short it was fun. There were a few hiccups along the way, GPA was great to work with, some patience is indeed required maybe due to age and cultural differences, but eventually everything worked out.
In regards to the sound, well whatever I write will probably not hold much weight but here goes anyways. The highs from the horn is incredible, I originally thought I would need a super tweeter to go with this, but now I don't think I'll need one. The lows are sufficient for what I listen to. The cabinet is around 300ltrs and maybe going up to 400 may change my mind, but we'll leave that to the next build. Overall I am happy with the results which is what matters most, it is much much better than what it replaced, I will have to build a new amp to fully utilise the speaker, the KT-88 that drives it is just too loud and harsh and moving down to a 2A3 will be the next step.
Thank you all once again for all the advise and help, I couldn't have done it without your help especially KF and GM. Until the next one.....
Well, just a short note on these. I am all in for fairy dusts and Santa Claus but never in my wildest dreams did I imagine that 'running-in' your speakers were actually a real thing!
Been using these for about 10 hours a day, it's been 20 days, so an estimate of around 200 hours of play and today I noticed for the first time how they have suddenly felt very very open.
When I first used them I felt they were a little harsh and jarring, but today it just seems to have mellowed out. Sound stage appears bigger, there is also more clarity.... I'm starting to question my sanity.
I do notice that when I really crank the volumn up the highs start sounding a little hollow/ cave like. I have the back, one side and the top padded out. Maybe I need more padding in there? Your thoughts fellas.
Been using these for about 10 hours a day, it's been 20 days, so an estimate of around 200 hours of play and today I noticed for the first time how they have suddenly felt very very open.
When I first used them I felt they were a little harsh and jarring, but today it just seems to have mellowed out. Sound stage appears bigger, there is also more clarity.... I'm starting to question my sanity.
I do notice that when I really crank the volumn up the highs start sounding a little hollow/ cave like. I have the back, one side and the top padded out. Maybe I need more padding in there? Your thoughts fellas.
Interesting! I guess the horn 'surround' GPA is using is somewhat stiffer initially than the old felt rings.
In the cab, one surface of any parallel surfaces should be damped as a given, but I'm thinking it's partially the horn resonating and why it needs a foam lip like was used on the Urei horns. I'm guessing that JBL, who owns Urei now, might not take too kindly to GPA adding them. I wonder if the Urei's replacements will fit, otherwise, time for a little DIY tweaking.
Another 'problem' is that the thick baffle has created a low pass filter chamber that's tuned very high and probably the main reason for any hollowness, so as nice looking as the cabs are, it may be necessary to heavily damp these 'tunnel' walls to both lower the chamber's Q and quell the theoretically infinite number of eigenmodes at one frequency as well as any reflecting off the horn if it protrudes beyond the woofer's surround.
For future reference, in high aspect ratio cabs it's best overall to use offset vertical wall bracing with either cross tie dowels or vertically oriented 1x3 bracing strips and either heavily rounding over the driver cutout or at least slope it >12 deg included to ensure any eigenmodes will rapidly decay away instead of being a 'one note' drummer.
GM
In the cab, one surface of any parallel surfaces should be damped as a given, but I'm thinking it's partially the horn resonating and why it needs a foam lip like was used on the Urei horns. I'm guessing that JBL, who owns Urei now, might not take too kindly to GPA adding them. I wonder if the Urei's replacements will fit, otherwise, time for a little DIY tweaking.
Another 'problem' is that the thick baffle has created a low pass filter chamber that's tuned very high and probably the main reason for any hollowness, so as nice looking as the cabs are, it may be necessary to heavily damp these 'tunnel' walls to both lower the chamber's Q and quell the theoretically infinite number of eigenmodes at one frequency as well as any reflecting off the horn if it protrudes beyond the woofer's surround.
For future reference, in high aspect ratio cabs it's best overall to use offset vertical wall bracing with either cross tie dowels or vertically oriented 1x3 bracing strips and either heavily rounding over the driver cutout or at least slope it >12 deg included to ensure any eigenmodes will rapidly decay away instead of being a 'one note' drummer.
GM
So, it's been a couple of months on these and only one thing is bugging me, the lack of bass.
Will increasing the port depth increase the bass?
Will increasing the port depth increase the bass?
It's a fairly insurmountable problem with that driver. The only thing that helps at all is working the room boundaries with an enormous box. Even then, I wouldn't exactly call them well suited for heavy bass.
Try placing close to the wall. If you've a room that is rectangular, please try placing along the longer wall.
My experience with the 604 (in a 620A cabinet) is that even by moving a couple of inches makes a huge difference in bass.
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