Mismatched speaker ohms?

#61
Electromancer said:
I just experienced some weirdness trying to respond to your reply from earlier. My reply was tacked into the quote I was replying to. Then I just made reply to no one. I think at least one of those was user error.
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Yes, I saw the reply. Thank you. I think you'll like the results with those drivers, if you choose to go that way. It'll go louder than you expect and the bottom end will be nice and tight. Another advantage of staying with a sealed cab in your case is the cab will be kept in its original state, a piece of Kustom history. Interesting project for sure.
 
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#62
First off I’d like to say thanks to everyone who chimed in here and especially to eniac for taking the time to run the modeling.

I got in touch with www.tedweber.com about reconing and it turns out that the damaged speaker was already re coned at some point. Thing is, they re coned it for 8ohms where the remaining speaker is 16 ohms. I guess this means it was one of the models that came with 2x 8 ohm cabinets for a final load of 4 ohms.

In the end I think what I will do is to place the single Eminence 8 ohm speaker that I have in the box and cut a piece of plywood to cover the remaining hole which I will place my port hole in. Then I can run it with my other cabinet that is 8 ohms. The other cabinet is one that I built a few years ago and loaded with a salvaged 8 ohm speaker from an old damaged 2x15 cab. Until this whole thread I knew absolutely zero about how impedance loads work and I had no idea what I was doing placing that speaker in it.

Thanks again to everyone. I may post some pics here when I get it all done.
 
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#63
Electromancer said:
This brings me to another simple question since you mentioned the nl series jack. I was planning on throwing in a standard neutrik 1/4” jack like you see in a guitar pedal. Would this be foolish and inappropriate in this context?
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1/4" is not great for high power stuff like bass or PA; it'll work safely with lower-power amps but speakon is far better

you can be clever and get a neutrik speakon "combo jack" that'll take both

1729289046843.png
 
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#64
what about the eminence beta 15A?

eminence.com

BETA-15A 15

Recommended for professional audio as a woofer in sealed and vented enclosures.
eminence.com eminence.com

it's described (and even modeled) as suitable for bass in sealed boxes and a pair would not be that expensive or that heavy

at 8Ω each, wire the cab parallel for 4Ω and you'd have a pretty cool "garage band" 2x15 bass cab (and being a padded kustom, if you get drunk at band practice and fall backwards into it you won't hurt yourself :D)
 
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#65
walterw said:
1/4" is not great for high power stuff like bass or PA; it'll work safely with lower-power amps but speakon is far better

you can be clever and get a neutrik speakon "combo jack" that'll take both

View attachment 7056643
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Exactly - 1/4" TS has "point contacts" where the bent spring touches the tip/barrel, while the speak-on has a much larger "Iinear contact" areas....
 
#66
walterw said:
what about the eminence beta 15A?

eminence.com

BETA-15A 15

Recommended for professional audio as a woofer in sealed and vented enclosures.
eminence.com eminence.com

it's described (and even modeled) as suitable for bass in sealed boxes and a pair would not be that expensive or that heavy

at 8Ω each, wire the cab parallel for 4Ω and you'd have a pretty cool "garage band" 2x15 bass cab (and being a padded kustom, if you get drunk at band practice and fall backwards into it you won't hurt yourself :D)
Click to expand...

I took a quick look at it. The midbass hump is similar. So is bass extension. It's a bit more efficient. But mechanical power handling would be less than half what he'd get with the Legends, although Xlim is respectable so there is a decent safety margin. Also an extremely pronounced mid peak centered at roughly 1.7 KHz, much higher in amplitude than the Legends. Would be tough to mitigate with normal (low Q) tone controls w/o attenuating surrounding frequencies, but might be reduced with a graphic if one of its center points was at or very close to that frequency. At only $50 less for a pair compared to the Legends, though, I'd call it a false economy. But I'm glad you mentioned it because it forced me to take a closer look.
 
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#67
eniac said:
I took a quick look at it. The midbass hump is similar. So is bass extension. It's a bit more efficient. But mechanical power handling would be less than half what he'd get with the Legends, although Xlim is respectable so there is a decent safety margin. Also an extremely pronounced mid peak centered at roughly 1.7 KHz, much higher in amplitude than the Legends. Would be tough to mitigate with normal (low Q) tone controls w/o attenuating surrounding frequencies, but might be reduced with a graphic if one of its center points was at or very close to that frequency. At only $50 less for a pair compared to the Legends, though, I'd call it a false economy. But I'm glad you mentioned it because it forced me to take a closer look.
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oh right, didn't see the legend; that one's touted as an actual "bass guitar" speaker that's happy in small sealed enclosures while the beta i mentioned is more of a generic PA speaker that's "OK" in sealed boxes
 
#68
You guys rule! I’ve got my eye on the legend but at this moment putting $340 in speakers into a box that I impulse bought for $100 isn’t feasible. Right now (7:30 am on a Sunday) I’ve just finished thoroughly cleaning and armor-alling the exterior and I installed the plywood panel and port over the lower speaker hole. I used a toilet flange and a 6” long piece of 3” pvc spray painted black. If I want a longer port I got a fitting that I can throw on to extend it. Shorter I can cut it and if I don’t like that I can always use the fitting to add back on. Once it’s late enough to start lugging things around in the house I’ll drag it in and toss in the delta 15lfa that I already have and then I will probably have to wait till this afternoon to try it out without drawing the ire of any family members.

I already had the speaker so by my math I’m out $10 bucks for the toilet flange and the armor all and $100 for the box. I’m probably gonna re cone the og speakers at some point and the possibility of getting new ones in the future is still on the table too so this could be an ongoing project. I need cool stuff to keep me busy so that’s fine by me.
 
#70
Is the port 4 inches in diameter?
If so and if you are still going to the Delta 15 LFA the port length is too long, for a 40hz tuning single port is going to be about 2 1/2 inches.
Guessing by the length of the port it may be tuning the cabinet into the 25hz area.

With a single port that size you may get some air noise "chuffing" sound from the port at high volume
 
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#71
Mike Caldwell said:
Is the port 4 inches in diameter?
If so and if you are still going to the Delta 15 LFA the port length is too long, for a 40hz tuning single port is going to be about 2 1/2 inches.
Guessing by the length of the port it may be tuning the cabinet into the 25hz area.

With a single port that size you may get some air noise "chuffing" sound from the port at high volume
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Agreed.
 
#73
Mike Caldwell said:
Is the port 4 inches in diameter?
If so and if you are still going to the Delta 15 LFA the port length is too long, for a 40hz tuning single port is going to be about 2 1/2 inches.
Guessing by the length of the port it may be tuning the cabinet into the 25hz area.

With a single port that size you may get some air noise "chuffing" sound from the port at high volume
Click to expand...
It’s 3” internal diameter pvc. I figured it may be too long. I plan on shortening it in place with my oscillating saw once I get to try it out. If you happen to easily be able to recommend a length at that diameter it might save me some time trying to fine tune it. Thanks
 
#75
Electromancer said:
It’s 3” internal diameter pvc. I figured it may be too long. I plan on shortening it in place with my oscillating saw once I get to try it out. If you happen to easily be able to recommend a length at that diameter it might save me some time trying to fine tune it. Thanks
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If your going to stay with 3 inch ID ports go with 2 of them just under 4 inches in length.
 
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#76
Mike Caldwell said:
If your going to stay with 3 inch ID ports go with 2 of them just under 4 inches in length.
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I’ll see if I can find a flange that will work with 4” pipe. I’m guessing that having a 3” hole and a 4” pipe with a reducer would kind of defeat the purpose. Or maybe I will try to find something that’s actually meant for this purpose rather than something I can go by right away at Home Depot. Seems like diy may not be working in my favor.

Edit: I can get a 4” toilet flange. I got three because I already had a scrap of 3” pvc.
 
#77
You don’t need a flange, just cut the correct size hole with a hole saw or router and slide the tube in. Attach with suitable construction adhesive.
 
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