Here is a post I copied on this exact subject written by the president of SP Technology loudspeakers.
Friends,
I just got a PM from a circle member that asked me the following question:
Quote:
I've read some recent articles that proclaim the advent of 4ohm speakers has been a poor trend in the speaker industry. What are your thoughts with respect to 4ohm loads, as they relate to the demands placed on the amplifier design.
My response turned into a dissertation before I was through (that's never happened before ). I thought, "Gee, I could post this on our circle and maybe piss somebody off!" Not that that's really my goal, but inevitably...
Anyway, heres my opinion on the matter - right from the mouth of god. (Note "god" is spelled with a little "g.")
As far as speaker impedance goes - I have my opinion. It sounds to me that whoever is making such claims is basing their opinion on the fact that they prefer low power, SET type amps. You can be sure it becomes an issue when using such equipment. The design philosophy behind the MRS products is totally based on accuracy of reproduction. The euphonic effects produced by low power (particularly tube) amps may "sound" good, but they are not a part of the original recordings in most cases. I suppose if they were, then you'd have a doubling of the effect when using such equipment with those recordings.
I've even used such "sweetening" myself at the show this year. We used the Modwright preamp in our setup and we could tell it was adding something to the high frequencies - something no other solid-state preamp ever did. The point is, although we suspected (I could be wrong ) the effect was a result of added harmonics at high frequencies, we liked it and it made for a better show presentation. If other folks do the same with their equipment, then we can hardly fault them for it.
But the upshot is that if you use your power amp to get those effects, there’s a secondary drawback. Low powered amps usually can’t supply the current needed to drive a 4-ohm speaker. Well now... there are many good, low impedance speakers out there that a lot of small amps will never be able to drive. If I were a betting man, I’d bet that many (not "all") makers of such amps would wish that all low impedance and/or lower sensitivity speakers would go away. That way their amps couldn’t be faulted for not being able to drive them. I’ll bet there’s more going on behind the scenes of these comments that you are referring to, than most audiophiles would never be aware of or even think about. It all has to do with the almighty $$$.
So…do I think there’s anything wrong with a 4-ohm speaker? Nope, not a thing – other than the fact it places higher current requirements on the amplifier - and that's not a failure in speaker design whatsoever. The whole thing is a front. As an example, I helped develop 40,000 watt amplifiers with DC - 20kHz bandwidths, that were designed to drive loads with a maximum of 1/2 ohm impedance and a lot of inductance (very hard to do) - back in my days at Crown. I left there after nine years back in 1996. Bleeding edge research (for back then) to be sure, but the production line ended up producing literally thousands of them for the Medical/MRI industry. The point is, with today’s technology, although it’s not a cakewalk…it ain’t exactly rocket science either. There is absolutely no reason any decent amplifier manufacturer can’t produce exceptional products of relatively high power and moderate to high current sourcing capability (i.e., easily able to drive 4-ohms). The only reason they don’t is because they like the euphonic sound of their smaller amplifier (which is fine), or they just aren’t smart enough to build bigger/better ones (their problem).
Whatever their reasons, the one thing they definitely need to do for sure... is to shut the hell up and quit trying to pass the buck on the speaker manufacturers! – implying that the industry has “lost its way” and is on the wrong path, yada yada. They now appear to have resorted to having their little “dis-information” hawkers (you don't want to know what happens to false prophets!) out there trying to spread their gospel of “big-amp = bad-amp” pseudo-techno-theology = bull s**t. However, they can’t do that directly or they would inflame the big amp manufacturers. That in turn would start a serious debate that would end up having them look like they're trying to make excuses for their amplifiers shortcomings. That would be just too obvious.
Instead, they’ve developed a very veiled and coy little diversion – blame it on the speakers. Yeah…right. If they ever heard any of our “bad” 4-ohm speakers on the right amp (not theirs) and front end gear, they’d be struck speechless – and then quitely back away looking pretty stupid.
-Bob
