[Radiator]

Hi everyone-

I have a pair of RM2's that I built myself about 5 years ago(maybe a little longer).  Love the speakers.  These were my first foray into do-it-yourself audio, as well as anything that has audiophile quality.  Brian was exceedingly helpful, answered my questions personally, etc.  I have been nothing but thrilled with the performance.  Lately, I have begun to move more of my equipment toward audiophile quality.  Awhile back I asked about amplifiers on this board, and among the suggestions I received was someone suggesting a used pair of Odyssey Extreme Monoblocks.  I made that purchase, and again heard quite a step up in terms of clarity and soundstage over my previous Yamaha receiver/amp combo.  I still use that for my preamp, until I can get the funds together for a new preamp.  I am leaning toward a Modwright 9.0SE in the future(like the reviews from guys on the Odyssey board), but that really has nothing to do with the question at hand.

Here is what I am really wondering.  When I purchased the RM2 kit from Brian, I went with 8 ohm impedance, because I used my Yamaha to drive speakers in another room (Bose), and thought that I would want to keep the impedance of the speakers all the same.  I was unsure how the Yamaha would do with differing impedances for speakers.  I now no longer use the Bose, and I am considering rebuilding the RM2s to be at a 4 ohm impedance.  I have not asked Brian if he would sell me a set of components to do this(I certainly suspect he would though), but just thought I'd ask the group here what their thinking was.  One reason I want to consider this is because even with all the power at my fingertips, the speakers could be louder.  I suppose this may be a function of the preamp I am using.  Are there other benefits to going with 4 ohm, such as speed of the speaker, etc?  Do the passive components go "out of tolerance" in time, making it a good idea to change this stuff out occasionally?  Any other ideas (other than  buying the latest VMPS, which is financially not appropriate now)?

Well, thats about it.  Thanks for any input you guys give me.  I am not all that knowledgeable regarding this stuff(as you can likely tell), but I know what my ears like.....

Thanks again!

[warnerwh]

Changing to 4 ohms will not make your speakers louder with the same amp because at 4ohms your amp will need to put out twice the current.  It may even cost you volume. You sound like you'd be a good candidate for a 200wpc or larger power amp.  You may be surprised how much more power may help the sound if you are pushing your present amp.  

Power gets used up very fast as only a 3db increase in volume, which is just slightly louder, takes double the power. So a 600wpc amp is only capable of 3 db more volume.  A 200wpc amp is only 3db louder than a 100wpc amp. If you like it loud at all 200wpc is a good idea in most any medium to large room. To make your speakers go twice as loud it works out to an amp that has 10 times as much power.  To complicate things even more an amp that has the better current capability can also sound more powerful than another amp that appears to be rated at the same power.  This is especially true when using 4 ohm speakers.

I'd call Brian personally about changing to 4 ohms.  There are some benefits but like I said earlier your speakers and listening habits sound like it requires more power.  Your crossover components should be in excellent condition as they're not near old enough to need changing. At the very earliest is 10 years and 20 years is far more likely.  
Hope this helps.

[Bob15]

What then are the benefits of 4 Ohm speakers over 8 Ohms?  As a downside it can overwork an amp which is pushed too hard which is never good.

[Radiator]

Thanks for taking the time to write a response.  Obviously, my knowledge level here is a bit lacking.  The Monoblocks I have should be more than adequate I believe.  The odyssey information on the website is lacking a bit on them, but I believe they would work out to about 250 watts, pushing nearly 200 amps.  Their website lists them at 180 watts, 120 amps, but these numbers (and the website) don't address the "extreme monoblocks".  I am not looking for "ear bleeding" volume, but the clarity is pristine even at full volume levels, and I was thinking that I could get more from them.  It seemed to me that my Yamaha RX-777 integrated amp/receiver obtained about the same volume level(with nearly half the wattage, though I know that it requires massive power to keep increasing volume level).  I was aware of the logarithmic wattage to decibel relationship, but I didn't realize that the speaker impedance had the same type of relationship.  Perhaps my preamp isn't driving the blocks to their potential.  Regardless, preamp upgrade seems to be the next priority for me.  

Thanks again for taking the time to explain some of this stuff to me.  I am relatively new to this stuff.  I am a digital engineer...should have taken more analog classes in college...not that I would remember any of it now.

[ZMan]

Radiator,

Big B can give you details of any benefits of such a conversion.  Other than a slightly warmer sound, I am less confident that it would be worthwhile.  However, a good pre-amp would upgrade your sound more than you are probably aware.  I owed a pair of RM2 Neos (4ohm) and originally ran them with a Yamaha receiver as a preamp and used a Tube amp for power.  This performed below my expectation.  The upper mids and treble was very irritating.  In this application the reveling nature inherent in the VMPS design worked against me.  I saved up and bought a good pre-amp and bingo!!, 3D sound, PRAT and envolvement, Wow!  While all the components of a system must be of equal quality, I have found the pre-amp to be the keystone piece.  Your power is fine.

Spend you funds on a good pre, you won't regret it.
Z