Ampeg SVT112AV Speaker replacement

[mike77rios]

Hi There! I have an Ampeg SVT112AV. The cab is 8 ohms. The speaker is 8 ohms. I want to replace the speaker with a 4 ohm equivalent for more power. I never use the tweeter. I should be able to do a straight switch right? Or, Do I have to separate the new speaker from the crossover and wire direct to the plug? I plan to use the Eminence Delta-12LFC. or do you have a better cost effective solution?
Any help will be appreciated!
Thanx

 

[agedhorse]

IMO, poor choice on both accounts.

1. Generally, you will give up some sensitivity when going from an 8 ohm to 4 ohm driver. This means that the additional power the amp may deliver doesn’t translate to much if any) increase in volume. In this case, the 4 ohm sensitivity penalty is ~1dB.

2. The particular driver you proposed is pretty dark and doesn’t generally work all that well without a tweeter (or mid driver). It’s also likely LESS sensitive than what you already have. In this case, the sensitivity of the proposed driver is in the 93dB/1W/1M. I would expect the driver in your cabinet is closer to 97-98dB, so in this case it would be a ~2dB step backwards.

3. this assumes that the cabinet is ideally aligned to the new driver (unlikely without changes) so the real world penalties in sensitivity, LF extension and power handling could be even worse.

 

[mike77rios]

I understand but this still doesnt tell me if I can connect direct or if I need to wire direct to input jack.

 

[agedhorse]

You would simply replace the speaker, but I don't think you appreciate the information I provided, nor why.

 

[basscooker]

Is there anything wrong with the cab as is? Might be more cost-effective to sell and look at other cabs. What you have now to buy speakers + sale of the cab= not a bad used budget for something to fit your needs better.

 

[Jaco who?]

A delta 12lfc is 140 bucks. A second 112av cab is 550. The logical thing to do is increase you budget by 410 dollars and just buy another one. Probably not what you want to hear, but that's how you get louder.

 

[agedhorse]

A delta 12lfc is 140 bucks. A second 112av cab is 550. The logical thing to do is increase you budget by 410 dollars and just buy another one. Probably not what you want to hear, but that's how you get louder.

Yes, adding a Delta 12LF (4 ohms) is not going to get him even close to 2 of the 8 ohm 112AV cabinets. Between the lower sensitivity and lower radiating area of the single driver, this is a lose-lose proposition (a step backwards IMO)

OP - what amp do you propose using with this? You may find that there's also nowhere near enough mechanical power handling on the delta.

 

[mike77rios]

Im old. I have bitchin cabs that are heavy as.....well you know. What I want is louder. I like this cabs weight. My thinking is if I put in a 4ohm speaker I can get the full 350 watts out of my Ampeg PF 350 at 4ohms. I dont want to spend alot of cash. I dont want to sell my cab. The Delta is just an example of the speaker I may replace.

 

[basscooker]

Ok.
You have an X gallon bucket, but need to move more water. Painting it a different color won't make it bigger.

What we're trying to explain is you're unlikely to make that cab better than Ampeg did. If you need more than it can do, it is what it is. Loud lives in moving air, not necessarily how much power you throw into the box.

 

[JimmyM]

Im old. I have bitchin cabs that are heavy as.....well you know. What I want is louder. I like this cabs weight. My thinking is if I put in a 4ohm speaker I can get the full 350 watts out of my Ampeg PF 350 at 4ohms. I dont want to spend alot of cash. I dont want to sell my cab. The Delta is just an example of the speaker I may replace.

You will never get any more out of that cab than what you’re getting, even if you replace the 350 with an 800. But you are going to ignore me anyway, so spend your money if you want, but don’t come crying to Andy or me when you discover it was a waste of time and money.

 

[agedhorse]

Im old. I have bitchin cabs that are heavy as.....well you know. What I want is louder. I like this cabs weight. My thinking is if I put in a 4ohm speaker I can get the full 350 watts out of my Ampeg PF 350 at 4ohms. I dont want to spend alot of cash. I dont want to sell my cab. The Delta is just an example of the speaker I may replace.

Ok, try to follow this...

Your amp is rated at 250 watts into 8 ohms and 350 into 4 ohms. The gain from 8 ohms to 4 ohms is 1.5dB

Your current 8 ohm speaker is rated at say 97dB/1W/1M, your current maximum SPL is: 97dB+24dB at 1M = 121dB at 250 watts at 1M

Your proposed 4 ohm speaker is rated at say 93dB/1W/1M, your current maximum SPL is: 93dB+25.5dB at 1M = 118dB at 250 watts at 1M

In this case, you lose a full 3dB of SPL which is the equivalent of playing your current speaker at 1/2 the rated 8 ohm power (or 125 watts).

What Jimmy was trying to get at is that the math is really quite clear (I do these calculations every day, it's my native language).

[edited for typo]

 

[paskisti]

@agedhorse You may want to fix your calculations. I think you mixed 93 and 97 db in them.

For OP: Guys are trying to say that even you utilise more power with 4 ohm driver it can turn less of it into audible sound so your cab will be more quiet with 350w and 4 ohm driver than with 250w and 8 ohm driver. If you want to be louder you need more speakers.

 

[agedhorse]

@agedhorse You may want to fix your calculations. I think you mixed 93 and 97 db in them.

For OP: Guys are trying to say that even you utilise more power with 4 ohm driver it can turn less of it into audible sound so your cab will be more quiet with 350w and 4 ohm driver than with 250w and 8 ohm driver. If you want to be louder you need more speakers.

Yes correct, thank you, (way) too much multi-tasking today while buried in the lab!

 

[baxter_x]

It's always absolutely amazing to see how some people keep on thinking they are on the right path despite the facts, math and great knowledge they are provided........

 

[beans-on-toast]

Add a second 112 for more volume. The two cabs will also give you the desired 4 ohms.

The best setting for a HF attenuator is the off position.

Any LF speaker is best avoided when used on their own.