8-ohm speaker w/4-ohm min load

lowend1 · #1 08-06-2010, 07:27 PM

I have a Peavey DataBass combo. You know the one - 450w into a single 15" 4-ohm BW that's rated at 300w. I hate BWs and was thinking of swapping in an Eminence Gamma 15A, which is an 8 ohm speaker. The DataBass wants a 4 ohm minimum load. How much of a power drop will there be, roughly speaking, with this combination?

username1 · #2 08-06-2010, 07:42 PM

You would loose about 1/3 power which should leave you close to 300 watts. The good thing is you will have the option of adding another 8ohm cab with it if you ever need it. I doubt you will notice the power drop very much.

billfitzmaurice · #3 08-06-2010, 08:14 PM

Quote:

Originally Posted by lowend1

I have a Peavey DataBass combo. You know the one - 450w into a single 15" 4-ohm BW that's rated at 300w. I hate BWs and was thinking of swapping in an Eminence Gamma 15A, which is an 8 ohm speaker. The DataBass wants a 4 ohm minimum load. How much of a power drop will there be, roughly speaking, with this combination?

The impedance is a minor issue, as is the power drop. What matters is the driver specs that determine how and if it will work in the cab. The Gamma 15 is displacement limited to only 100 watts.

lowend1 · #4 08-07-2010, 05:46 AM

Quote:

Originally Posted by billfitzmaurice

The impedance is a minor issue, as is the power drop. What matters is the driver specs that determine how and if it will work in the cab. The Gamma 15 is displacement limited to only 100 watts.

I've heard the phrase "displacement limited" before, and if I'm understanding correctly, it is related to the speaker's mechanical abilities. Beyond that, however, I'm not sure how it translates. Are you saying that the Gamma 15A will not hold up - period? How does it compare to the OE 1502-4 BW in the same regard? If it's any help, the DataBass has a tiny enclosure that measures 17"w x 16"h x 9-3/4"d internally, with two round ports on the bottom that exhale directly downward. I'm looking to tighten up the sound of the amp, and am not so much concerned about huge lows (generally speaking I'm a "small speaker" guy). Thanks for the assist.

billfitzmaurice · #5 08-07-2010, 07:26 AM

Quote:

Originally Posted by lowend1

I've heard the phrase "displacement limited" before, and if I'm understanding correctly, it is related to the speaker's mechanical abilities.

Displacement (Vd) is the product of cone area (Sd) and xmax. The Gamma 15 and 1502-4 have similar displacement, so they have similar output capability. If you want higher output capability the driver wattage rating is relatively moot, displacement is what really matters. As far as 'tightening' the sound of a cab that small, load it with a ten or twelve. It's half the size necessary to get anything but boom when loaded with a fifteen.

lowend1 · #6 08-07-2010, 07:37 AM

Quote:

Originally Posted by billfitzmaurice

As far as 'tightening' the sound of a cab that small, load it with a ten or twelve. It's half the size necessary to get anything but boom when loaded with a fifteen.

I thought about doing that - I got the amp at a very reasonable price, so experimenting is not out of the question. Have to work out a way of retrofitting / modifying the 15" baffle...