RTiA9: Question regarding Amps

[Squishy Tia]

Yewwo :)

I recently purchased a pair of RTiA9s to replace my aging (highs were muddy) Yamaha NS-A100XTs. Yeah, I know, way lower league there. :P I have a couple questions.

My receiver is a Yamaha HTR-5860, which specs to 95w/chan x5, 8Ω, but has a 4Ω option. Should I be placing the receiver in its 4Ω mode to be safe (and will it make a difference in available power to the speakers)? The manual for the receiver does show dynamic power range increasing as the amp approaches 2Ω (roughly 50% increase from 8Ω -> 4Ω, which one would expect with a decent quality amplifier power supply).

The other question is, will this amp, regardless of the mode used above, be able to power the speakers well enough? I've seen the recommendations for 200w/ch amps and above to really "push" the speakers, but my room isn't that big (it's a moderately sized bedroom). I would like to know if I'm straining the amplifier, and if so in any way, whether or not the cause is related to my first question.

Thank you for your time! :)

- Squishy Tia!

[Kex]

... My receiver is a Yamaha HTR-5860, which specs to 95w/chan x5, 8Ω, but has a 4Ω option. Should I be placing the receiver in its 4Ω mode to be safe (and will it make a difference in available power to the speakers)? ...

The other question is, will this amp, regardless of the mode used above, be able to power the speakers well enough? I've seen the recommendations for 200w/ch amps and above to really "push" the speakers, but my room isn't that big (it's a moderately sized bedroom). I would like to know if I'm straining the amplifier, and if so in any way, whether or not the cause is related to my first question.

Thank you for your time! :)

- Squishy Tia!

Squishy, welcome to the Club! No, those are 8Ω speakers, so do NOT switch your amp to 4Ω mode.

Yes, you would probably benefit from more power, using either an external amplifier (your receiver does have pre-outs for that), or a more powerful receiver. Those are very big speakers and owners frequently complain they are not getting the bass response they expected. In the meantime, you should be OK though.

If you do decide to get extra amplification, the 200w/ch recommendation is probably more valid for more difficult speakers than those, such as some of the bigger models in the 4Ω LSi range. In your case, if you only have two speakers to power, the cost of quality extra amplification will not be that high, especially used.

[leroyjr1]

You should look at a used good condition Adcom amp to wake those babies up.

[Squishy Tia]

No, those are 8Ω speakers, so do NOT switch your amp to 4Ω mode.

Just a clarification - the receiver's manual states that switching to 4Ω mode puts the receiver into "4Ω mininum" mode, indicating 4Ω or higher speakers are safe to use. I know on Yamaha receivers at least, switching to 4Ω min mode loses a slight bit on the damping factor, but nothing noticeable. I was more curious to see if it would free up a bit more power to the speakers.

Currently I'm only powering these two speakers. My room's setup doesn't really allow for the full 5.1 setup in terms of placement. I'd be tripping over wires all day if I tried that. I do have at least a Yamaha YST-150 sub (gotta love subs that go down to 20Hz, which most do not).

What I'm basically wondering is why the 4Ω mode wouldn't be safe (as you noted). From what I understand, the speaker is going to draw the same power regardless of whether or not the receiver is in 4Ω mode, since it was designed to operate on an 8Ω optimized current stream, and that the receiver's mode settings were designed to activate additional capacitance to handle the increased current draw of a 4/6Ω speaker.

[Kex]

... What I'm basically wondering is why the 4Ω mode wouldn't be safe (as you noted). ...

I did not suggest it would not be safe, but on that setting, since 4Ω speakers are harder to drive, it probably just limits itself to prevent damage. With 8Ω speakers, especially big ones like those, you would probably get worse results if you use the lower setting, because of the imposed limitation on output. I may be wrong on this of course, but some of the other guys will know more about it when they get around to reading your post.

[Squishy Tia]

I did not suggest it would not be safe, but on that setting, since 4Ω speakers are harder to drive, it probably just limits itself to prevent damage. With 8Ω speakers, especially big ones like those, you would probably get worse results if you use the lower setting, because of the imposed limitation on output. I may be wrong on this of course, but some of the other guys will know more about it when they get around to reading your post.

I'm getting what you''re saying. If I recall correctly, Yamaha had notes on that years ago too. Thanks for the clarification. So basically, since my receiver is capable of driving 4Ω speakers, I'm in the clear, though obviously not "up to snuff" for gut punching bass,

I'm not worried too much about the bass aspect right now since I have a sub capable of dipping down to 20 Hz. You wouldn't think that's much of a dip below 35Hz (the average for most subs), but...play Chrono Trigger and listen to Crono's sword swipe. You WILL notice a huge "swoosh" down in the 25 Hz range on a low frequency capable sub. :) Scared the crap out of me the first time I heard it, as I thought something had sliced through my walls, it was that powerful.

I'm mainly just wanting to make sure I'm not straining my receiver, especially since I have to ramp the volume to between 25-20db for some material (usually NES/SNES emulation from my Mac Pro since those systems/games default to a much lower (-10db) base volume setting.

[Kex]

... I'm mainly just wanting to make sure I'm not straining my receiver, especially since I have to ramp the volume to between 25-20db for some material (usually NES/SNES emulation from my Mac Pro since those systems/games default to a much lower (-10db) base volume setting.

Squishy, those volume knob scales are not universal, so it depends on what the scale on your receiver is, and if you have calibrated it or not. As a dummie's rule, for a receiver like that, I would suggest keeping it at least twenty "clicks" (of 1dB each) away from it's maximum setting, whatever that is. Anywhere higher, and you are risking blowing the tweeters on your speakers because of insufficient power output, and the resulting distortion/clipping, especially with bigger speakers such as those you mentioned.

If you have calibrated it though, this will all depend on how you calibrated it, so even twenty clicks could be a dangerous level in that case.

[Squishy Tia]

Yeah, I'll be looking for an external two channel amp dedicated for these puppies soon when the budget permits. A question on that - Yamaha's manual (which so far has been better on info than most other manufacturers' manuals) suggests putting the external amp's volume knob at max, and using the Yamaha receiver to adjust main volume. Is there any inherent danger in doing this?

[Kex]

... Yamaha's manual (which so far has been better on info than most other manufacturers' manuals) suggests putting the external amp's volume knob at max, and using the Yamaha receiver to adjust main volume. Is there any inherent danger in doing this?

Not that I know of, no. It makes perfect sense, in fact, since you will calibrate all the channels with the Yamaha initially. A lot of amps do not have a volume knob anyway.

[F1nut]

A lot of amps do not have a volume knob anyway.

Yeah, like 99.5% of them.

[VR3]

Just a FWIW --

When you switch that 4 ohm switch on a receiver, you are actually reducing the current and it will distort much much faster.

Leave it in 8 ohms, even if you are driving 4 ohm speakers.

[Squishy Tia]

For now, budget and availability being prime concerns, I'm running these speakers off of an Onkyo M-282 external amp via the Yamaha's Pre-Outs. It's nice to have bass again. This amp should drive the speakers well enough, right? I'm not using them at exceedingly high SPLs since my room isn't exactly huge. I'd have gotten an Adcom or Niles, but cost and the inability to find them relatively easy (for any price in the Bay Area) + limited funds put that option out for now.

On the bright side, I can knock a few db off the sub's settings (it's at 0db flat level right now) with the speakers picking up more bass. :)

Edit: Contra (Arcade, played through M1; www.bannister.org/software/) and Akumajo Densetsu (Japanese Castlevania 3 played through Audio Overload (same site) sound awesome now, showing much much more detail.