What does moving from a 150 watt amp to a 400 watt amp get you?

Robertjason75, to add to Willemj’s questions and comments, as I alluded to in the last paragraph of my lengthy post yesterday I don’t think that for most listeners the capability of cleanly producing 105 db peaks at the listening position is necessary on most or all of their recordings. And I believe that a majority of audiophiles do not have systems providing that capability.

And even though as I mentioned I listen to a lot of classical symphonic recordings that have been engineered with minimal or no compression, and consequently have extremely wide dynamic range, that I listen to at average volume levels of perhaps 75 db or so, there are relatively few recordings in my collection which will reach brief dynamic peaks in the area of 105 db. (In addition to basing that conclusion on SPL measurements I have performed using a Radio Shack digital SPL meter set for fast response and C-weighting, I have used a professional audio editing program on a computer to examine the waveforms of some of the widest dynamic range recordings in my collection. Doing so readily allows me to determine the full amplitude of even the briefest high volume transients, and compare it to the average level of the recording).

So without knowing what kinds of recordings you listen to, or the answers to Willem’s questions, my guess is that you don’t have a problem.

Regards,
-- Al

A correction to a miswording in item 2 of my previous post.  When I said ...

...for a 4 ohm impedance the SPL produced in response to an input of 2.83 volts will be 3 db less than if the spec had been based on 1 watt, since 2.83 volts into 4 ohms corresponds to 2 watts.

I should have said:

...for a 4 ohm impedance the SPL produced in response to an input of 1 watt by a speaker whose sensitivity spec is based on 2.83 volts will be 3 db less than if the spec had been based on 1 watt, since 2.83 volts into 4 ohms corresponds to 2 watts.

Regards,
-- Al
 

Bruce, thanks for providing the Musical Fidelity writeup, which is excellent IMO, and is similar to some analyses I have provided here in the past. A couple of minor nits:

1)The reference to SPL (sound pressure level) falling off at 6 db per doubling of distance applies to most non-planar (box type) speakers. The rate of fall-off for planar speakers such as electrostatics is significantly less.

2)More often than not sensitivity is specified as the SPL produced at 1 meter in response to an input of 2.83 volts, rather than in response to 1 watt. For an 8 ohm impedance those results will be identical, since 2.83 volts into 8 ohms corresponds to 1 watt, but for a 4 ohm impedance the SPL produced in response to an input of 2.83 volts will be 3 db less than if the spec had been based on 1 watt, since 2.83 volts into 4 ohms corresponds to 2 watts.

In any event, Stereophile measured the OP’s speakers as providing an SPL at 1 meter of 89 db in response to an input of 2.83 volts, which corresponds to 1.6 watts into what I would consider to be its 5 ohm impedance (see my earlier post regarding the 5 ohm figure). 1.6 watts is about 2 db more than 1 watt, so the speaker will produce 87 db in response to an input of 1 watt. The 240 watt capability of the amp into 5 ohms (again, see my earlier post) corresponds to about 24 db more than 1 watt. Two such speakers listened to at a distance of about 10 feet when driven with 240 watts will produce an SPL of approximately 87 + 24 + 3 -10 = 104 db, very close to the 105 db minimum recommendation provided in the paper.

And as I mentioned earlier, an amplifier capable of providing 400 watts into 5 ohms would add very little to that figure, 2.2 db to be precise. Unfortunately, IMO, it appears that very few of the responses by the others have focused on the OP’s situation in a comparably specific manner.

All of this assumes, btw, that the speakers are capable of handling these high power levels without significant thermal compression or other non-linear effects becoming significant. I have no knowledge of the maximum power handling capability of the Revel Ultima Studio 2, or of how well it would perform as its power handling limit is approached.

I would add that while I personally listen to a lot of classical symphonic recordings that have been engineered with minimal or no dynamic compression, and consequently I have stated in some past threads here that 105 db at the listening position is the minimum peak volume capability of any amp/speaker combination I would consider (which happens to coincide exactly with the paper’s minimum recommendation), my perception has been that the majority of audiophiles do not listen to recordings that when played at their preferred volume levels would come anywhere close to such high peak levels. With peak levels not exceeding even 90 db in many cases that have been mentioned in past threads here. I believe the main reason for that is the high degree of dynamic compression that most recordings in various genres, especially pop and rock, tend to be engineered with.

Thanks again. Regards,

--Al

Correction to my previous post:  In the first paragraph "music music" should have been "most music," of course.

Regards,
-- Al
 

I would make several points:

1)As a practical matter what you are using with this particular speaker is a 240 watt amp, not a 150 watt amp. The amp is rated at 150 watts into 8 ohms and 300 watts into 4 ohms. The impedance curve of the speaker, as shown in Stereophile’s review, indicates an impedance averaging about 5 ohms across almost all of the frequency range below 1 kHz, which is the part of the spectrum that encompasses most of the energy of music music. It can be calculated from the 150 watt/300 watt 8 ohm/4 ohm numbers that the amp is capable of 240 watts into 5 ohms.

2)The difference between 400 watts and 240 watts is about 2.2 db, which while not quite negligible is not much of a difference.

3)IMO design differences between amplifiers are likely to be vastly more significant from a sonic standpoint than a 2.2 db difference in maximum power capability.

4)Everything else being equal more amplifier watts = more amplifier $. IMO it is usually desirable to have as high a percentage as possible of the dollars one chooses to invest in an amplifier go toward quality rather than toward watts, assuming the number of watts is sufficient to avoid getting near the amp’s clipping point.

Good luck. Regards,
-- Al