Originally Posted by Doner Designs
I think I know the answer based on reading the posts in this thread, but to ask a slightly different way, is there any difference in TONE in either of the following two setups.
Let's presume for simplistic discussion that I have two similar amps but one has roughly 4 times the power of the other. For example, one has 100W into 8 ohms and the other has 400W into 8 ohms.
Lets say we hook up a pair of 8 ohm drivers in series to the more powerful amp (to present a 16 ohm load). Lets further assume that the resulting power is roughly 200W into the 16 ohm load using the 400W amp.
For the other example we use the 100W amp but use the same two 8 ohm drivers in parallel (to present a 4 ohm load). In this example assume that the smaller amp puts out roughly 200W into the 4 ohm load...the same as the bigger amp into the 16 ohm load.
I realize that there will be more headroom with the bigger amp, but let's assume we are not anywhere close to clipping with either amp. If you like think in terms of 1000 and 4000 watt heads instead of 100 and 400.
The bigger amp has a lot more flexibility and the smaller one will run hotter, but will there be any difference in tone between these two setups? What about output/loudness?
Another way to put it - pickups sound different in series vs parallel wiring. What about speakers?
Its a theoretical question. I'm just curious.
One practical application might be to err on the side of buying a lot more watts than one needs and send them into speakers that are wired in series to increase their ability to safely handle the excess watts.
The only good reason to wire two 8 Ohm speakers in series is if you plan to do the same with another pair, so you can wire each pair parallel, to create an 8 Ohm load of if the amp was designed for a 16 Ohm load. There's no other benefit and definitely no advantage WRT output level. The output of two identical drivers wired series will be the same as one driver- the added cone area's benefit will be canceled by the higher impedance.
WRT the original question- yes, there's a difference between using a 4 Ohm cabinet and an 8 Ohm cabinet. If someone needs the maximum output from 200W with a 4 Ohm cabinet with specific sensitivity, the 8 Ohm cabinet of identical sensitivity needs to be driven by a more powerful amp and more power costs more money.
This is assuming all other aspects of the amps are equal. If the person plays in a wide variety of venues and the largest requires higher output but there's no guarantee of having a PA to reinforce the sound, more power and/or cabinets is an absolute "must-have".
A rig with more power than necessary with 8 Ohm speakers and stable into 4 Ohms is about the best way to go- a second cabinet can be added without having to worry about the amp puking and the level at any amplifier control setting will be higher than it was with one cabinet. In extreme cases, using a main amp with line out or true bi-amping is going to yield higher output, due the ability to feed more amplifiers and, therefore, more speakers without impedance issues/problems.
Pickups sound different in series/parallel connection because the impedance has a direct effect on the circuit's characteristics and performance- the extra inductance changes the frequency response of the signal coming in by acting as a filter. The inductance of a speaker voice coil isn't as high and, with large speakers, not enough to make a noticeable change to the response when the signal going to them doesn't have extended high frequency content. Buying too much power for 16 Ohms is a lot more expensive than "just right" for 4 or 8 Ohms. I would use 8 Ohms as a target and 4 Ohms as the lowest load/max power limit. If you want compression and growl, you would be better off finding an amp with a gain/boost/master volume control than low power- with low power, you can run out of headroom and power.