RTi150: 170 wpc for highs, how much for lows?

Sparky · December 2003

My receiver has 140wpc x 5, 170wpc x 2. I want to bi-amp my mains (RTi150). If I use my receiver to power the highs, how much power do I need for the lows? Is there a rule of thumb, or percentage of power (high/low) that I should I looking for?

Thanks,
Sparky

organ · December 2003

Not really. Just make sure you use a good amp. I'm sure a 100wpc amp with good clean power will make the woofers on your 150's sing.

Don't forget to match amp gain with the receiver when you bi-amp.

Maurice

brettw22 · December 2003

It doesn't make sense to me to put more power to the highs and less to the lows. Reverse what you're planning and you should be fine. The gain issue is a big one so that you're not being totally blown out by one over the other.......

Sparky · December 2003

I was thinking around 200 wpc for the lows would be the minimum. What kind of results are people getting from bi-amping? Good? Bad? I'm just not sure that is the route to go but it sure would save me a lot of money as opposed to buying two 350+ wpc amps.

I welcome all comments.

Thanks,
Sparky

steveinaz · December 2003

Personally I think the results (of bi-amping) are far too subtle to be worth the expense. Of course, if you're independantly wealthy--knock yourself out.

Sparky · December 2003

SteveInAz,
Since you don't feel bi-amping is necessary for the 150s, are you suggesting that 170 wpc is sufficient or do you have an alternative solution?

Thanks,
Sparky

steveinaz · December 2003

I'm saying that your money is better spent on 1 really nice amplifier, than 2 mediocre amps. I don't know the efficiency of the speaker in question, but typically 170 watts/rms would be sufficient; but having said that, you buy the most power you can afford--as the extra headroom is always nice.

I would rather spend $1000 on a very good quality 200 watt/rms amp, than $500 each for 2 lesser quality 200 watt amps.

OK: the RTi150 is rated at 91db; given that, you could rock to pretty serious levels with 170 watts/rms--now the quality of the amplification will be your only limiting factor. Is it good, clean power? Is it a high-current design? A speaker that nice deserves some top-notch amplification. Typically the amp section in a receiver will not rival your better seperate amplifiers, simply because of space limitations in receivers, though Denon has a good reputation--I've never owned one, so I can't speak from first-hand knowledge.

I will say this, if those pups (RTi150) were mine, I'd run (not walk) to my local Parasound dealer and get an HCA-1500A and a set of high-quality speaker cables; but thats my opinion.

Sparky · December 2003

SteveInAz,
Thanks for your input, I couldn't agree more about spending money for one quality amp as opposed to two of lesser quality.

I'm trying to get some feedback from current owners of the RTi150s to see how much power they feel is needed. I guess it varies widely according to listener preferences. I've read everything from 100 to 500+.

I think the Denon 5600 is good enough to power the highs while using a quality amp (like the 200 wpc Parasound) for the lows. This will give me around 350 wpc which is where I would like to be for this system. I may be wrong but that's why I'm here. I need some advice.

The reason I keep going back to bi-amping is because I don't think 200 wpc will be enough for these speakers and didn't want to spend $2000 for a 350+ wpc amp.

Sparky

BTW: the Parasound looks great.

steveinaz · December 2003

No problem. Though 200watts/rms into a 91dB rated speaker will get you some pretty incredible levels. Oddly enough, you should always use your "best" amp for the mid/highs in a bi-amp scenario. These are your most revealing frequencies...

brettw22 · December 2003

Steve,

I get that the mid/high's are the most revealing, but does that mean that they ultimately need as MUCH power to them as to the sub/lows in a bi-amp type setup? That doesn't seem right to me......though, bi-amping doesn't seem entirely right either.......

nico · December 2003

I'm using an EARTHQUAKE CINENOVA GRANDE 5 amp for my RTI50'S. Tha amp is rated 300watts x 5 and let me tell you it's an awesome amp for the price I paid for it. Tha bass on the RTI50's never sounded so full than when I was just using the receiver that I had running it before (SONY 4ES). If you want to know more info on the EQ here is a link earthquakesound.com

Nico

steveinaz · December 2003

Originally posted by brettw22
Steve,

I get that the mid/high's are the most revealing, but does that mean that they ultimately need as MUCH power to them as to the sub/lows in a bi-amp type setup? That doesn't seem right to me......though, bi-amping doesn't seem entirely right either.......

don't confuse "best amp" with "most powerful amp"...we're speaking in terms of quality, not quantity.

You're right, bass frequencies require more power--but if you have 2 amps that are fairly close in terms of output, you should use your better quality amp for your mid/high section. This is why its usually recommended that you bi-amp with matching amplifiers. This way the outputs are matched--of course not everyone has the bucks to do it this way...

...In my opinion, if you're going to bi-amp (I don't anymore); do it right. Get 2 high quality matching amplifiers and some high-end speaker cable. Any less than this, and you are wasting your time...and money.

Sparky--I would recommend that you watch the "Flea Market" for a used Carver amp to power your low frequncies. Quite often there are fantastic deals on vintage Carver stuff--and its tuff as nails. 200 watts/rms is plenty for thr Rti150, unless of course, you have them in a gymnasium.

Sparky · December 2003

Perhaps I have assumed something I shouldn't have. I thought my Denon receiver's amp section was fairly high quality. In Stereo mode... 140 watts RMS x 2 @ 8 ohms w/ 0.05% THD. I thought this would be more than adequate to power (both quality and quantity) the highs on the 150s. Then I would use a quality 200wpc amp for the lows.

Guys, and ladies, don't be afraid to tell it like it is. If you don't like this setup let me know. I'm just learning about this stuff and would appreciate input from you more experienced "audiophiles". Even if you disagree, I would rather hear from you now than after I purchase additional equipment.

Sounds like many of you are not too keen on bi-amping. The exception being if you had two identical amps. Is it because it's difficult to match the output levels to highs and lows? Sound quality issues?

So much to learn...

Thanks,
Sparky

TroyD · December 2003

IMO, there is a WORLD of difference between a receiver amp and a separate power amp.

The analogy that I like to use (paraphrasing George Grand) is a receiver is more like a 4 cyl engine and a power amp is more like a big beefy V8. Both will cruise you along at 75mph but the 4cyl has to work a LOT harder with less oomph than a V8.

Not a perfect analogy but you get the idea.

Look, you guys that say that you NEED 200wpc to drive these 150's....the specs just don't support it. I've got more inefficient and power hungry speakers that I've driven with MUCH less power (power amps, NOT receivers) to levels that make your head hurt.

Just my .02

BDT

steveinaz · December 2003

TroyD:
That has to be the best anology I've heard, and describes the differences perfectly.

Sparky:
Personally, I think your system is fine as is. As I stated before, 170watts is alot of power to a 91dB rated speaker--but you sound as though you are determined to bi-amp; so my advice was heading in that direction....

See my post in "2-Channel" on bi-amping.

RVJII · January 2004

I know what you are going through as I just went through this with my RTi12's. I was just using the receiver (110 x 7) and it sounded great. After reading here for several weeks I decided to upgrade. As mentioned above, the advantages of bi-amping are pretty subtle. (several forums) I was looking at doing something simalair to you, using my receiver for the highs and a 2 channel amp for the lows. The whole gain matching was looking like it would be a real problem though.

Anyway, I decided to forgo the bi-amp idea and for $574 picked up two Outlaw M-Blocks (200 x 1). I used the FR/FL pre-outs from the receiver to the M-Blocks and then bi-wired them to my mains. Let me just say this...it did make a rather noticable difference and for the price you can't beat it. If you are going to be spending some cash anyway you might want to take a look at them.

Just my $0.02

Sparky · January 2004

Hi RVJII,
Thanks for the input. I already purchased a 200wpc amp. It hasn't arrived yet and haven't decided whether to bi-amp or not (using receiver for highs and amp for lows). I guess I'll try it both ways to see how it works for me.

I do know that my current setup (170wpc in stereo mode) is not enough to drive the 150s as I would like.

I'm sure some will correct me if I'm wrong, but I believe that when bi-wiring you should use one amp to power L/R highs, and the other amp to power the L/R lows. I'm not sure why and maybe that only applies if you are using two different amps. Hopefully someone with more experience will respond.

Coincidentally, I did look at the Outlaw M-Blocks. I probably would have gone that route but found a great deal on a lightly used Denon POA-2800 (200wpc).

Sparky

Tour2ma · January 2004

Sparky,
The Denon amp purchase should make a nice match for your AVR. I'd use the amp to power the L/R lows and the AVR for the L/R highs.

BDT,
You know I'm a separatist as well, but it's the separation of the amplified and low level signal duties that's the key. There are receivers out there that are as powerful as many amps (say bridged M-400's). But also true that bridged 42's will out run any receiver I can think of...

Anyway the 150's issue is current demand in a HT set-up. Been documented time and again since last October...

Steve,
In case you missed it:
... the 150's issue is current demand in a HT set-up. Been documented time and again since last October...

While I mildly disagree with your arguments against bi-amping in a 2 ch rig, IMO your stance does not apply in a HT situation such as Sparky's.

On one hand making a comment,

"Of course, if you're independantly wealthy--knock yourself out,"
and in the next breath,

"I will say this, if those pups (RTi150) were mine, I'd run (not walk) to my local Parasound dealer and get an HCA-1500A."

is just not being responsive to the situation.

RVJII · January 2004

Originally posted by Sparky
I'm sure some will correct me if I'm wrong, but I believe that when bi-wiring you should use one amp to power L/R highs, and the other amp to power the L/R lows. I'm not sure why and maybe that only applies if you are using two different amps. Hopefully someone with more experience will respond.

Sparky [/B]

Sparky,

I edited my above post as it was a bit unclear. Anyway, what you described is bi-amping rather than bi-wiring. In bi-wiring you use one amp but use a cable that is split (internal bi-wire) or has a double run. At the amp end the cable goes to one channel's binding post while at the speaker end it goes to both the high and low binding posts. (with plates removed, of course.)

Sorry for the confusion and hope that clears up what I was talking about. You'll have to post how your new set up works out as I'd be curious to know since I did consider doing the same.

Sparky · January 2004

RVJII,
Sorry about that. I was describing bi-amping but typed bi-wiring, my mistake. The amp should be here next Tuesday. I'll keep you posted.

Tour2ma,
I appreciate your encouragement on my selection. I've been out of touch with audio equipment for over 20 years. A lot has changed and I'm trying to get re-educated. I will try setting up the amp and receiver two different ways.

Setup 1: use the amp only to drive the RTi150s.

Setup 2: use the receiver to power the L/R highs and the amp to power the L/R lows, as you suggested.

Thanks for the help,
Sparky

RTi150: 170 wpc for highs, how much for lows?

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