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My .5 Aligned Sealed 610 Build

#62
astack said:
Here's my (first) stupid idea of the day: Could you make it an open back chamber? You're already passing above where I think the box would have much effect. You could make it a removable panel like on typical guitar cabinets so you could go screw it back on to seal it in the future.

Another alternative is you might go back and find a driver with a lower sensitivity to avoid the resistor.

Anyway, glad to see you're still messing with DIY stuff. :D
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I'm sure an open back chamber would work but I want this to be an easily reversible mod without violating the integrity of the box. After all that work I just can't get myself to rip into that exterior. The Barefaced 69er makes it work in a closed box.

Driver sensitivity is not the problem here. Too much current through an 8 ohm driver at applied voltage is. The resistor bank creates a voltage divider which reduces voltage across (and current through) the driver to keep it within design limits and avoid the magic white smoke. I think the sensitivity, frequency response, and sound characteristic of the Copperhead make it ideal for this application. There are also not that many 10" guitar drivers that handle 75 wrms. This thing should crank.
 
#63
bassboysam said:
I've always wondered about the .5 alignment. I understand that by lowpassing half the speakers you improve dispersion but don't you also lose a lot of volume/response from all the frequencies above the filter?
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Overall output of the upper mids and highs seems to be reduced producing a slightly darker sound but 1/8 turn up on the upper mid and treble knobs on the amp put it back where it should be - not a problem.

gwangi said:
Please get some vids up so we can hear how this cab sounds.
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The Nordie-equipped Valenti PJ5 through a GK MB Fusion 800 sounds excellent through this cab. I have a Zoom H4N and MacBook Pro with Garage Band but haven't been satisfied enough with my initial attempts to post them. :rollno:
 
#64
5StringPocket said:
I'm sure an open back chamber would work but I want this to be an easily reversible mod without violating the integrity of the box. After all that work I just can't get myself to rip into that exterior. The Barefaced 69er makes it work in a closed box.

Driver sensitivity is not the problem here. Too much current through an 8 ohm driver at applied voltage is. The resistor bank creates a voltage divider which reduces voltage across (and current through) the driver to keep it within design limits and avoid the magic white smoke. I think the sensitivity, frequency response, and sound characteristic of the Copperhead make it ideal for this application. There are also not that many 10" guitar drivers that handle 75 wrms. This thing should crank.
Click to expand...

10-4. Hmm, could the resistor be placed in a recessed cage on the exterior? Still requires some retrofitting, but less intense than the whole back chamber.
 
#65
I did a quick test to get a feel for what this contained heat might be like. I used the smallest lamp I could find and made a 3-sided cardboard insert for a 5 gallon bucket with the middle section securing a piece of mattress topping. A meat thermometer inserted through the cardboard was then used to measure the temperature. Here is the test rig:
HeatTestRig_zps476cb751.jpg

The bucket was placed upside down over the lamp with a couple boxes to provide proper height. Here is the Jack-o-lantern test rig:
HeatTest_zps4e528059.jpg

It was apparent pretty quickly that a 100 watt bulb was too much. I swapped it out for a 60 watt bulb and left it for about 15 minutes. The bucket was hot to the touch and even though there was no effect on the mattress topper or any funny smell, the thermometer was pegged at 200 DegF. I repeated the test with a 40 watt refrigerator bulb and left it for 20 minutes. The bucket wasn't as hot to the touch and temperature had lined out at 175 DegF but that is still too hot to work with.
astack said:
10-4. Hmm, could the resistor be placed in a recessed cage on the exterior? Still requires some retrofitting, but less intense than the whole back chamber.
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It could and I'm sure it would effectively dissipate the heat but there are a couple other options to consider.
One option is to use a 16 ohm instead of an 8 ohm speaker. With a 16 ohm pad this would be a 32 ohm branch with 56.25 watts across the resistors and another 56.25 across the speaker. This reduces resistive heat dissipation by half versus using the 8 ohm speaker which would be more manageable. The 16 ohm, 60 watt Celestion G10 Vintage might be a good candidate here. From the specs Fs=115Hz, so 2*Fs=230Hz hi-pass frequency. For this 16 ohm driver, a 250V, 43uF metallized polypropylene capacitor can provide that 1st order high pass.
Invalid Link Removed

The first thing to try though might be to just partition off the upper left chamber and provide a 1st order high pass at 200 Hz with the existing Weber 10FL. A 250 V, 25 uF capacitor should work here. From previous testing done by Chris and others, isolating the chamber and filtering out the bass generates a different mid/high response which might make an audible difference. If it sounds good it might be worth installing a switch to select full range or high-passed.
 
#66
Here are some cross posts about using a Celestion G10. It seems to be a better efficiency match for a 610 (97dB/w vs 99dB/w for the Copperhead) and with 50% less waste heat dissipation for impedance-matched circuits I think it would be a better choice for this cab.
kringle77 said:
For this mornings experiment, I ran 7 of the neo's and 1 celestion guitar 10" high-passed at 500hz. Sounds great! Maybe better than with the two mod10's. Im so tempted to bring it to the gig tonight but, the berg is already loaded in the truck and the weather is pretty crappy so, I guess thats what I'll be gigging with tonight. The only other top end driver I'd like to try is the eminence Copperhead. That has the right tonal profile. Probably better than the celestion even.
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will33 said:
Which Celestion?
BTW, I'm liking the Mod. It's spl profile is almost a dead on match for running over my single 1505 BW 15". Ends up with a little dip around the 1khz nasally area with fat lowmids and a nice top that's not overly bright/harsh.
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kringle77 said:
Sweet Will. It's the celestion G10. One is enough to keep up with the 7 neo's.
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#69
Sorry about that. If Eminence offered a 16 ohm version of the Copperhead I'd use it but the 8 ohm impedance along with my little heat study makes it a deal breaker for me. It would be possible to mount power resistors on an aluminum heat sink and make an external plug in module like astack suggested to work with the 8 ohm speaker, but it would be Frankencab enough that I don't think I'd be able to find a buyer if I made that mod.

At $175 that G10 Alnico Gold is very expensive. Even at $95 the G10 Vintage is at the top of what I'm willing to spend to finish tricking out an already expensive cab. Thanks for blazing the trail first so it's not another unknown.
astack said:
Thumbs up for the garage science experiment. :D
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Where would we be today without garage science experiments?
 
#71
People do it all the time. Sometimes it's okay, other times not so much. No shortcut for proper engineering and design considerations.

I've got 10s, 12s, and 2 kinds of 15s (LF and non), all different flavors of good and have their purpose. For max low end two 3015LF's will definitely bring the goods but for a punchy vintage tone without the extended highs and lows of a modern 3-way the sealed 610 driven hard sounds very good. They just sound different - more than one tool in the workshop.
 
#72
kringle77 said:
Geez, I was hoping someone would try the copperhead so that I could hear about it without buying it myself. :smug: I've got a celestion g10 alnico gold as well that is "IT". But, it's super expensive.
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Copperhead was OK, I liked the G10 better. Do you want my Copperhead?
 
#74
I've got 10s, 12s, and 2 flavors of 15s (LF and non), all different flavors of good and have their purpose. For max low end two 3015LF's will definitely bring the goods but for a punchy vintage tone without the extended highs and lows of a modern 3-way the sealed 610 driven hard sounds very good. They just sound different - more than one tool in the workshop.
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No need to justify that here. TB is a safe space for gear amassing. Save the 'splainin' for your live-in.

The "problem" with DIY'ing music equipment is that doubles the number of tools ya need.
 
#75
JGR said:
Copperhead was OK, I liked the G10 better. Do you want my Copperhead?
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Good to hear another confirmation for the G10 - ordered one last night from Parts-Express.

astack said:
No need to justify that here. TB is a safe space for gear amassing. Save the 'splainin' for your live-in.

The "problem" with DIY'ing music equipment is that doubles the number of tools ya need.
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:smug: My wife is pretty understanding but I don't like to amass too much - keeps you on better footing elsewhere.
Sometimes the tough choice is where to thin the herd.
 
#79
Thanks. I'm not much for noodling in front of a camera because it's like the proverbial blank slate but at least I know my Zoom H4 works into Photobooth on my MacBook. I'm trying to get snapshots before and after isolating the upper left chamber and swapping in that Celestion with a 200 Hz high pass. I want to try and redo the "before" video with somewhat structured 4 to 8 bar phrases from about 6 songs with different styles, then do an "after" take with the same sequence to see if there is an audible difference. A friend of mine used iMovie to edit some home video into a pretty cool holiday sequence so I'm thinking this same app might work for interleaving before and after sequences. Ed Friedland is very good at this technique and I'm no Bass Whisperer but I can't think of a better way to convey what this sounds like. New ground...
 

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