ZDoug Posted November 17, 2002 Share Posted November 17, 2002 I know the disadvantage of 4 Ohm speakers. They put more strain on amplifiers by drawing more watts.However,there must be advantages to a 4 OHM design vs an 8 OHM one.Does anyone know what they are?I know some expensive speakers have the 4 OHM design so it must not be an expense issue? Also just how good an amplifier do you need to drive 6 or 7, 4 ohm speakers in a HT set up. Will the B&K 507 have a good enough amplifier section to drive all speakers with out problems? Quote Link to comment Share on other sites More sharing options...
MrMcGoo Posted November 18, 2002 Share Posted November 18, 2002 Good electrostats have sonic advantages, but you pay for the advantages in more ways than one IMO. Electrostats are all low impedance and have near zero bass without conventional woofers or subs. Very low sensitivity as well, but they sound good to some people. Low impedance speakers like M&K and B&W are loved by high end shops; they are high margin and help sell lots of big amplifiers. M&K and B&W sound marvelous with lots of amplification, but I personally prefer the live sound of Klipsch. I also don't mind avoiding the cost of Krell amps. There are inherent sonic advantages to horns. Search this site and you will find lots about the advantages. The sound and Vision site has lots of information/opinion on B&W and Paradigm. Bill Quote Link to comment Share on other sites More sharing options...
Deang Posted November 18, 2002 Share Posted November 18, 2002 You specific question regarding the B&K 507 is best addressed by B&K technical support. Send them an email via their web site. Quote Link to comment Share on other sites More sharing options...
WMcD Posted November 18, 2002 Share Posted November 18, 2002 One reason they are used may be that they are more sensitive, all else being equal. If you half the resistance, and keep the input voltage the same, then you should get twice as much power out. It is only 3 dB. But maybe someone thinks that is worthwhile, particularly if you have some high efficiency horns on the mid and tweeter. I suspect there are more complex issues. For example, there are some tradeoffs in the size of the voice coil and the size of the magnetic gap. One other thing is that the inductor used in the crossover can be of a smaller value with a driver having a lower impedance. So it is marginally less expensive. The use in a horn loaded speaker is something different. The effect of the horn is increase the impedance seen at the terminals of the speaker. At maximum efficency the impedance doubles. So it is best to start off with a low impedance driver. Gil Quote Link to comment Share on other sites More sharing options...
cluless Posted November 18, 2002 Share Posted November 18, 2002 There may be an ohm in moment But there's very few folk in focus..ELP Dagnabbit they didnt tell me how many ohms...Oh Watt the flock Quote Link to comment Share on other sites More sharing options...
MrMcGoo Posted November 18, 2002 Share Posted November 18, 2002 One advantage of low impedance, low sensitivity speakers is that the amps that drive them tend to run in the zone where total noise and distortion is very low. My RF-7s tend to run below 3 watts at all times. Most solid state amplifiers have very high percentage THD at this point. Hence many Kilpschers use tube amps that are clean at low wattage. I use a very quiet Pioneer solid state amp. M&K and B&W etc. require much higher wattage. Good solid state amps have lower THD as wattage rises, provided they are not pushed into clipping. Then there is the small speaker vs. large debate..... Clu- I love your posts. Bill Quote Link to comment Share on other sites More sharing options...
prodj101 Posted November 19, 2002 Share Posted November 19, 2002 my Mcintosh amp runs .1 distortion from 0 watts to 105. Quote Link to comment Share on other sites More sharing options...
John Warren Posted November 19, 2002 Share Posted November 19, 2002 ---------------- On 11/18/2002 10:29:40 PM MrMcGoo wrote: My RF-7s tend to run below 3 watts at all times. Most solid state amplifiers have very high percentage THD at this point. Hence many Kilpschers use tube amps that are clean at low wattage. I use a very quiet Pioneer solid state amp. ---------------- What do you consider high distortion? A good ss amp is .2% (.002 fraction) total distortion below 3W. You've been listening to the tubies! Quote Link to comment Share on other sites More sharing options...
MrMcGoo Posted November 19, 2002 Share Posted November 19, 2002 John, Multi-channel solid state amps do have a bit of noise at low ouput. Take a look at the B&K 7260 information at Home Theater mag. There are solid state amps that are quiet at low wattage and I gave an example. Noise varies by manufacturer, but does tend to go down as output increases. You may be right, the tube people may be getting to me. Maybe Clueless has a remedy. Bill Quote Link to comment Share on other sites More sharing options...
Invidiosulus Posted November 19, 2002 Share Posted November 19, 2002 "One reason they are used may be that they are more sensitive, all else being equal. If you half the resistance, and keep the input voltage the same, then you should get twice as much power out. It is only 3 dB." Don't forget(I'm sure you didn't) that every 3dB increase doubles the volume. Hence the decibel sytstem being exponential. Peace, Josh Quote Link to comment Share on other sites More sharing options...
John Warren Posted November 19, 2002 Share Posted November 19, 2002 ---------------- On 11/19/2002 4:14:34 PM MrMcGoo wrote: John, Multi-channel solid state amps do have a bit of noise at low ouput. Take a look at the B&K 7260 information at Home Theater mag. There are solid state amps that are quiet at low wattage and I gave an example. Noise varies by manufacturer, but does tend to go down as output increases. You may be right, the tube people may be getting to me. Maybe Clueless has a remedy. Bill ---------------- Bill- I don't know about HT amps but amps made from McIntosh that use autoformers to couple to the loudspeakers have .005% (.00005 fraction) total distortion at 250 milliwatts output to full rated power which, in the case of the MC602 is 1.2kW! Quote Link to comment Share on other sites More sharing options...
MrMcGoo Posted November 20, 2002 Share Posted November 20, 2002 John, A McIntosh MC206 amp reviewed by HomeTheater mag has a typical noise curve. It drops steadily until 75 watts. http://www.hometheatermag.com/showarchives.cgi?120:2 The noise curve is very good, but low wattage has a bit higher percentage of noise. Bill Quote Link to comment Share on other sites More sharing options...
John Warren Posted November 20, 2002 Share Posted November 20, 2002 What do you mean by *noise*? Are you referring to Signal to Noise ratio? I'm referring to published values of IM and nth order harmonic distortion. Quote Link to comment Share on other sites More sharing options...
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