RTi 150 = large or small?

walk · September 2003

These speakers really do have some good low bass. 20hz (26hz at -3db)

They don't really move enough air to be used without a subwoofer, but still - I say set them to Large and let them bump out some good bass, why choke them off when they can handle it? Then just carefully adjust your sub to add some boom to your low-end oomph and you're rockin.

What do you all think?

walk · September 2003

Let's take my setup. RTi150s set to Large, center and surrounds set to small. Sub is a small but potent CSW 8" 50watt.

With my old small-ish mains, I set them to Small and used 200hz (maximum) for the sub filter. With the Polk 150's set to Large, this produced too much "boomy" bass (in the 200-150 range I'd say).

After literally 2 days of playing with it, using everything from stereo music (FM, CD, and Vinyl!) to Pro Logic TV shows like Star Trek:TNG to DTS-ES dvd's, I find that a sub setting of about 110hz, with Polks set to Large, gives me satisfactory results. Right now I have the output level balanced for direct stereo-mode music, but find that I have to turn it up about 6db (which I can easily do with the reciever) for good LFE performance on DVD movies.

Does this seem like a good setup?

mantis · September 2003

You could set them to small depending on the flexability of your internal crossover or bass management of your pre amp or receiver.I wouls allow the sub to play from 32hz and down.

Otherwise set to large and don't look back.

Dan

walk · September 2003

Reciever is an older Onkyo, it has no options other than sub yes/no and speakers large/small. I'm fairly certain that the crossover freq for small -> sub is 80hz but there is no option to change it.

The subwoofer manual says to set the crossover at 160hz or higher when used with a Dolby Digital reciever. This makes sense if you use Small setting speakers (I just maxed it out at 200hz to avoid double-filtering). But with Large mains I think there is too much overlap, so a setting of about 110-120 is better (leaves plenty of room around 80hz and to be honest, the Polk 150s need some boost around 100hz and below).

Tour2ma · September 2003

In the final analysis, it's what sounds best to you in your room. That said...

I think your different findings with stereo and movies makes sense. With the sub in place the movie LFE should be only going to it, even with your mains set to large. And if I read you right, the 6 db boost you give the sub for movies is compensating for its inadequacies, because it's all alone on the really deep stuff. Try setting sub to "no", which should route LFE to the 150's, and see if any boost is needed.

The boominess you heard with the sub's filter set above 110 Hz (approaching the upper limit of true bass) is likely due to wave interaction from multiple bass sources in the 110 to 200 range.

What are you driving the 150's with? They are off 3 dB at 26 Hz. I can't imagine your sub can say the same. Given enough power, the 150's should kill your 50 W / 8" sub. Corner placement is the only hope it should have of having any impact.

walk · September 2003

The Onkyo 575 is an older 5.1 reciever, 70w/ch. I'm sure it's weak for the 150's, but the 50w sub fills in nicely.

Tour2ma · September 2003

Yeah... the 150's are definitely underpowered.

You don't specifically mention having surround speakers. If you don't, there may be a way to use 2 "extra channels in a bi-amping scheme. Might produce some benefit. but I don't know your AVR so can't say for sure whether it's possible...

In any case, this is one of the rare occassions I'd suggest you think about wiring the Polk way. Would seem to give you more control in blending. And if you can "bi-amp", routing the low frequency speaker leads via the sub, and the highs direct to the 150's might be as good as it'll get for now...

In any case won't hurt to play the above as you can always return to the "as is" set-up.

Have fun....

walk · September 2003

I have a 5.1 setup with center and surrounds.

The AVR main speaker outs go directly to the 150's, the sub is fed by the subwoofer pre-out (RCA) on the AVR, with sub = Yes.

You think I should run the AVR mains into the 150's high freq inputs, and the sub's speaker outs into the 150's low freq inputs? Basically turning the low end of the 150's and the sub into 1 big subwoofer, all fed off the 50w amp in the sub?

Sounds interesting, but then don't you lose the bass management of the center + surrounds which are set = Small?

Tour2ma · September 2003

No.... Sorry, I'm confusing you... That bi-amp scheme was if you did not have surround speakers and could utilize those channels as mains. You have surrounds so forget it.

In any scheme that wires main outs to sub and then sub outs to the main speakers, the AVR is still powering the mains, not the sub.

Does your AVR have pre-outs for the mains? If yes, a modest, 100 wpc or so power amp could help.

nico · September 2003

:cool: :cool: :cool: Anyone have any opinion or experience with OUTLAW AMPS. particularly the model 200? I'm thinking of getting 2 to power my 2 fronts (RTI50) for 2 channel music listening. Can I hook them up with my SONY 4ES receiver? If so can I also run them simultaneously for surround? Thanks for any help. NICO

Tour2ma · September 2003

nico,
Suggest you start your own thread over in electronics and/or get Frank Z's attention via PM. Frank is Outlaw #1 'round here...

Kinda derailing walk's thread here....

nico · September 2003

:cool: :cool: Thanks man

walk · September 2003

Thanks, I'm learning.

I think the reason why it's louder in stereo/DPL mode is that it passes a full-range signal in that mode, I mean that's usual for most AVR's correct? So if I set the sub's xover to 120hz, it is outputting 120-20hz. But then in DD/DTS 5.1 mode it only passes the LFE and 80hz LPF'ed bass to the sub out, right? So it's only doing 80-20hz and going to be not as loud... make sense?

As far as power levels, I think I'm ok. To give you an idea, using the internal test noise, if I set the volume to 0db, the Rat Shack meter reads about 72db from the center channel. I then calibrated all the other speakers to that. SO with everything calibrated to about 72db, I typically listen at volume levels between -30db and -20db readings. 40-50db in other words, not very loud - I think I got enough power for this apartment (and I know my neighbor who works nights would agree with me...

Tour2ma · September 2003

walk,
I think the stereo mode signal depends on your AVR's settings. It offers you the same "large/ small" and "sub - yes/no" options, doesn't it? If yes, and you're set to "Large/ Yes" for 2 ch operation, then the LFE is the difference.

Low listening levels you mention helped me make more sense of some your situation, so yes, power should not be an issue.

Dr. Spec · September 2003

Walk, you've got a slight misunderstanding of the calibration and volume issue.

The internal AVR test tones are mastered at "about" 30 dB under Reference Level. So if you calibrated to 72 dB at Master Volume 00 on your internal test tones, you would be seeing (at Master Volume 00) SPL peaks of 102 dB from any surround channel and 112 dB from the LFE channel (since the LFE channel is always boosted 10 dB by your DD/DTS processor).

At Master Volume -20, you would be seeing SPL peaks of 82 dB from the surround channels and 92 dB from the LFE channel.

This is assuming your sub channel is running flat. This is rare and most people run +3 or +4 on the sub . If that is the case, add 3-4 dB to the numbers above.

40-50 dB is barely audible, BTW. Sound pressure operates on a log10 scale and is not linear. In other words, 100 dB is not twice as loud as 50 dB.

Doc

walk · September 2003

Thanks, that makes sense and jives with what I've been measuring (volume at -20 gives me readings of 80-90db).

I have my computer hooked up to the AVR now (via SPDIF) and I found a test tone generator for windows, I'm going to conduct some tests.

RTi 150 = large or small?

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