Bass Management Setup and Rti70, Csi40

neato

I have a Toshiba XA2, 7 Marantz MA-500 mono amplifiers, 4 Rti70's a Csi40 center channel, and a Crystal Acoustics 12" subwoofer hooked up to a FBQ2496 BFD. I use the 5.1 analog outputs and with the powered subwoofer connected to the subwoofer output. The left and right channels are each bridged for 360W. There are each connected using a pair of in-wall speaker wire that appears to be 14AWG or 12AWG. I have the wires on the back of the speaker each connected between the set of banana plugs using shorter wire. When I change the setting for the left and right channels to small, there is a +6dB increase. I do not currently have a receiver. These are in a dedicated home theater with room treatments. I setup the levels using DVE.

I would like to know what speaker size anyone would recommend I should set these speakers for on my XA2.

Fongolio

Those RTi70's can handle fairly low frequencies. I'd set the speaker size to large. Same as the center (CSi40 drivers are almost identical to the RTi70's). I'd then set the sub to crossover between 50 and 80 Hz depending on your taste and room setup. I have the CSi40 center and it is great. The Rti70's I have now do surround duty as they were bumped from the front by a pair of fantastic RTiA7's.

neato

Thank you Fongolio. I have done some further testing with them set to large. I have found that if I let my amplifiers warm up for awhile before setting up the system with DVE, it works very well and with them all set to large as you have suggested. All channels measured the same for a nice 70dB calibration at limited bandwidth pink noise without variable volume on the back of the subwoofer being used. I could set it higher maybe but for my 20.5' X 13' X 7.5' room, it is about right for a high level of output. I set levels inside the player to -3 except the subwoofer which is at 0 and they seem to play very well. My receiver is out on repair but I will be able to use one once I hear back from them. It is nice to know I can get them sounding good as large.

kuntasensei

Large = full range. In digital surround, that means 20Hz-20kHz. CSi40's -3dB point is 50Hz... so clearly, it isn't made to be run as Large for digital surround. RTi70's -3dB point is 40Hz... again, clearly not Large. Why anyone would run these as Large is beyond me. Will they sound good with music that way? Sure... because music doesn't require much in the lower ranges. But for movie soundtracks, frequencies that low are regularly placed in those channels, so if you aren't crossing them over in any way, not only are you generally missing out on those frequencies, you're over-stressing the speakers (and likely muddying up the sound and using more power than you need to drive them).

Unfortunately, SMALL usually equates to an 80Hz crossover, which is high for those speakers. One of the best things to happen for speakers such as these are receivers and pre-pros that let you set independant crossovers at a digital level for each channel. I'm running RTi70 mains, CSi40 center and 4 RTi28 surrounds using an Onkyo TX-SR705 (with a SVS 20-39CS+ sub, 1,000w Samson amp and Buttkicker LFE). My crossovers are tailored to each speaker to get the most out of them while limiting output below the speaker's natural rolloff. My RTi70s are crossed over at 60Hz to give them a half-octave above their -3dB point to prevent significant dropoff as the crossover makes its transition. My CSi40 is crossed at 70Hz for the same reason (though it could probably handle 60Hz). If your current receiver doesn't let you do this, I recommend an upgrade. You'll be surprised by how well you can tailor each speaker's response, and you'll get MUCH cleaner sound from them by not pushing them below their designed limitations.

As far as the on-subwoofer crossover goes, defeat it entirely. Don't use it. Turn it all the way up above 120Hz, especially if you're running the other channels as large. The LFE channel carries audio all the way up to 120Hz (where it is brickwall-filtered, hence the .1 of 5.1 - it takes 1/10th of the bandwidth of the other channels). If you're running any of the channels as Small, you should DEFINITELY defeat the crossover on the sub, since the two crossovers can cascade, causing frequency gaps. More than that, the crossover circuitry can induce delay that will affect proper distance/delay settings, potentially throwing the subwoofer out of phase with your other speakers even if measured distances are correct.

ONE HUGE CAVEAT FOR THE DVD VERSION OF DVE: DVE's subwoofer tone is completely useless for calibration. On a digital level, it is incorrect. Many suspect that the root cause is that they forgot the LFE channel is supposed to get a +10dB boost during decoding and they didn't compensate for it (which is why Joe Kane insists it was correct at the encoder). Ed Mullen (now of SVS) confirmed this through ground plane testing, and I confirmed it by digitally extracting the .1 channel from the 5.1 track and running it through frequency analysis. Not only is the subwoofer tone encoded at the wrong level, it is not a 40-80Hz tone as DVE's package insert claims (and as you should be using to properly set subwoofer levels). If you use DVE to set subwoofer level, you're actually setting your subwoofer about 7dB lower than it should be if using a C-weighted SPL meter (due to the +10dB boost of LFE and the effect of C-weighting on the reading).

neato

I didn't get a manual with the receiver so it has kind of been a hit or miss with setup. I recently found out I was looking at the wrong model number and these manuals are available to download. The remote for the VXS-1012K is also compatable with a 45TX which is said to be the same model. If I can use that version manual to setup the analog and possibly even more than just a trim level which Pioneer states is a feature on the AVR's, then I will really be in good shape...I think. I was able to use the small setting with the AVR before without much trouble. The problem with setting them to small now is that the imaging appears off when I do so. Hope to correct this later somehow. I have since adjusted the left and right speakers to aim slightly behind me for a more wide sweet spot. It does seem to help and I have not tried a small setting after that. I will be getting a Integra pre/pro soon after we sell a home. This room is for HT. If I want to listen to music I have my Ipod, Denon 5200 amp, and another pair of Polk Rti70's in another room. I know better than to put a CD in the player right now. I can adjust it to -12 all channels and it will still be to loud for my taste for music.

My subwoofer does not have an adjustable XO. It has two switches, one for volume THX-Variable, and one for phase control Normal-Reverse. It has the volume dial knob on it also of course. That is connected to the feedback destroyer where I remove a couple small peaks at around 30Hz and 60Hz.

I currently use a 80Hz XO although I have used a 50 before with my AVR since the auto-setup has placed it there. I am concerned that if I set my XO at 50 instead of 80, I will need to worry about what effect this might have on how my room sounds more. The test results of my room with Pseudo-anechoic loudspeaker frequency response meausurement software look like it is indicating a 80Hz might be more appropriate, at least for now. The lowest XO the XA2 will do is 80Hz, and I see no reason of having a lower crossover at this time instead of having True-HD and other formats at higher bits available with the analog.

Dennis Gardner

Every room is different but my experience is that, tower speakers or not, the mid ranges on the RTi70s clean up alot when the deepest bass is taken off from them. 6 1/2 inch woofers just don't handle the mids of voice and sub-bass at the same time very well. It makes the vocals sound very boxy. I always filter my largest front towers when using a sub for HT, but run them w/o the sub full range for 2 channel listening.

Basically, full range is an entirely different animal for movies than it is for music.

neato

Correction about previous post: 30 Hz and 50Hz peak, not 60Hz.

Dennis Gardner wrote: »

Every room is different but my experience is that, tower speakers or not, the mid ranges on the RTi70s clean up alot when the deepest bass is taken off from them. 6 1/2 inch woofers just don't handle the mids of voice and sub-bass at the same time very well. It makes the vocals sound very boxy. I always filter my largest front towers when using a sub for HT, but run them w/o the sub full range for 2 channel listening.

Basically, full range is an entirely different animal for movies than it is for music.

I will try doing an A/B comparison with some material that has bass and sub-bass. I set all my speakers to small and the limited bandwidth pink noise on the subwoofer for DVE on the HD-DVD side went from 70dB to 64dB, so I turned this up again to 70dB where the other speakers now still measure at. I did a large to small change before and I thought I measured a +6db increase for the LCR and surrounds. Does that seem like it is working correctly? I thought this would measure higher for the subwoofer if I set them to small since I am sending more information there.

neato

A full bandwidth pink noise seems to setup the speakers alright. Can anyone please explain why the subwoofer is measuring at a higher SPL with the speakers set to large for the limited bandwidth pink noise and what this means?