genek

I hope so. When I'm playing my music I don't want to be able to pick out each individual driver in my speakers.

That hurt my eyes. Try these.

Do the specs for that amp actually say it's rated for 4 ohms in bridging mode? Most bridging amps that are rated for 8 or 4 ohms in standard mode only support 8 ohms when bridged.

What it says is that the distortion is rated from 20-20k at any power output up to the rated max, not that it's going to actually deliver that max power over the entire frequency range. It outperformed the specs, but in those days most AR stuff did. Original spec sheet attached. AR AU spec sheet.pdf Pre-1974, amplifier power specs were often smoke and mirrors with a lot of weaselly language. You can't compare vintage watts without deciphering the code.

Yes and no. If you're only looking at modern stereo tube amps, then all you need to do is look at the specs. But if you are throwing vintage amps into the mix, then understanding the differences between all the ratings methods that have been used over the decades is important when looking at something that says it delivers "60 watts."

Yes, as far back as the late 50s-early 60s, most higher-end audio specified RMS watts, though they often provided IHF and "music power" as well. There was a fair bit of wiggle room in RMS power as well. McIntosh manual for the MA-230 (1963) specifies continuous power (RMS), but power, distortion and frequency response are separate values, that is, power and distortion are not specified at any frequencies. The 1968 AR amplifier manual doesn't seem to have any specs in it at all. The separate spec sheet for it specifies RMS power and frequency response, and gives distortion across

Yes, but that's the AR amplifier, not the recommended power for AR speakers.

My guess is they were talking about pre-1974 RMS, measured with a 1kHz test tone. An amplifier measured with that method would have a rating 15-20% higher than one measured with the 1974 standard.

IMO, it's probably more important that all the drivers (woofer, mid, tweeter) are at the same *heights* as their counterparts.

From 1974 on, yes. Prior to that, power ratings, even in RMS, were usually measured with a 1kHz test tone and not across a frequency range. In 2000, the FTC caved to manufacturer pressure and reduced the preconditioning requirement for testing. From 1974 to 2000, amplifiers were required to run at 1/3 of their claimed output prior to testing; after the 2000 rule change, that was reduced to only 1/8. So when comparing amplifiers manufactured from 2001 on to ones from 1974-2000, reduce the power of the newer models by about 15%. Also, FTC amplifier ratings do not apply to multichannel

Are you using an actual power meter to determine that you are putting out that much power, or just making as estimate based on where the volume control is set? Output power is signal-dependent. With music, you probably have a steady output of around 10W or less.

If your amp or receiver was made anytime after 1974, its specs will state what the RMS power is. If you don't have a manual for it, check on hifiengine.com. For older models that give ratings in "IHF power," "music power," "dynamic power," "total power," etc., RMS power will be somewhere between 1/3 and 1/2 of what is claimed.

You have somewhere around 25WPC of real RMS power. I probably wouldn't try any ARs larger than the AR-2 series or its successors, i.e., a single 10" woofer.

A slight upward tilt will project sound a bit toward the ceiling. If you have standard 8ft high flat ceilings, this will result in a bit more reflection off the ceiling that may be changing the reverberant field more to your liking. If you have 16ft high, vaulted ceilings the effect will be negligible and the difference in sound is probably mostly in your imagination.

The dome mids and tweeters are designed to produce semi-hemipherical emission, so if they are working properly parallel should work best. If you have replaced the tweeters with HiVi units you have somewhat "beamier" highs and toeing in a bit may sound better. The ideal wall placement is actually set into the wall, as in a bookcase surrounded by books, but the closest I ever got to that with mine was in one of those old "entertainment center" wall units. They're now on stands about six inches from a wall and some windows.