[ReggieG]

Hi - I'm getting around to TRYING to set up my home theater/music right, after no doubt doing it WRONG all these years.

The equipment (all classic).

Sony STR-DA3300ES 7.1 Receiver.
Mirage fronts and center (OM-7 floor standers, Mirage OM-C2)
Mirage sub (BPS150i)
No side surrounds.
Rear surrounds (on stands) - currently Boston VRM-50; soon to be replaced by NHT C3.

Starting with a simple question. My connection from receiver to sub is single RCA from Sony receiver sub-out jack to sub-in on the Mirage sub. According to the subwoofer manual " This method does not remove low frequencies from your main speakers, and they will continue to reproduce bass frequencies."

The other sub option is to set it up as "high level" with cables - but I do not see that supported by the receiver (only has an RCA out).

Finally, there is an RCA connection to a XOVER jack on the Mirage sub. According to the manual "This method by-passes the subwoofer’s built-in level and crossover controls; subwoofer functions are controlled by the external crossover. (See External Crossover Owner’s Manual for details).

SOOO... My assumption is if setting it from sub-out on the Sony receiver to the XOVER input on the Mirage sub, this means that the receiver's auto- or manual calibration overrides ANY manual twiddling I do with the knobs on the sub? That is - if I set the cross-over via the receiver set-up screen to small speakers/80hz or whatever it is that's recommended, then the RECEIVER sends the "turn on sub" signal when appropriate, and nothing I do on the sub itself (which has a rotary "subwoofer" level control, a rotary "LP filter" control, a Phase switch, and a LF EQ switch) has any bearing on the sub output?

In which case, if I want to set up my system "for dummies" and do all the bass management via the receiver, I should switch the RCA jack from its current "Subwoofer" input to the "Xover" input on the sub, correct?

More to come, I am sure.

Thanks! Reggie

[Doublej]

Yes. If you want to use the receiver to control the output level and crossover frequency for the subwoofer then you should plug the rca cable into the XOVER jack on the subwoofer.

Once you do this you can confirm that the knobs on the subwoofer will not affect the output by twiddling them and not hearing any change in the sound coming from the subwoofer.

In this configuration the receiver should control the low frequency cutoff of the L/R speakers.

[ReggieG]

Thank you.

Now - before performing calibration for dummies:

The receiver manual says (in the section on auto-calibration):

1) "When a sub woofer is connected, turn on the sub woofer and turn up the volume beforehand. Turn the MASTER VOLUME knob to just before the midpoint."

Q: On the Mirage sub, I assume this is the Subwoofer Level Control knob, correct? (sw manual says: "This rotary control adjusts the output level of your MIRAGE subwoofer and should be used to balance the level of the subwoofer with that of your main satellite speakers."

2) "If you connect a subwoofer with the crossover frequency function, set the value to maximum"

Q: On the Mirage sub, I ASSUME this is the LP Filter Control, correct? (sw manual says: "This rotary control adjusts the high frequency roll-off of the subwoofer. Continuously variable from 50Hz to 100Hz, it is used to precisely match the subwoofer bass reproduction with that of your main/satellite speakers." So turn to the 100Hz position?

3) "If you connect a sub woofer with an auto standby function, set it to off (deactivated)."

Q: On the sub, it says "Your subwoofer is equipped with a special “Auto-on/Auto-off” circuit. This circuit automatically turns your subwoofer on as soon as it senses a program signal. At a predetermined time after the program signal ends, this circuit automatically turns the subwoofer off." However - there is no indication to turn this feature off, so I'm assuming nothing to do about it, correct?

4. I'm assuming the "Phase Switch" and "LF EQ Switch" can be ignored if not mentioned (also - if interconnect is on XOVER input of the sub)?

Thank you!

[Doublej]

1. Correct. This is the LEVEL knob on the subwoofer.
2. Correct. This is the LP FILTER knob on the subwoofer.
3. Correct. Do nothing. You have no ability to set the sub to always on.
4. Possibly Correct, Possibly Not Correct. It's not clear if these controls are bypassed when using the XOVER input on the subwoofer. You should set the Phase Switch to 0° and the LF EQ Switch to 0dB just in case they are not.
 

[ReggieG]

Thank you again, Doublej - resetting the switches for final(?) test when new rear speakers are in.

Having run an audio calibration with the existing set-up (hadn't changed the switches yet on sub, but did set Level/LP Filter as instructed) - I will note that the auto-calibration overrode the manual setup for the speakers that I did. After running the AC, it sets all speakers to LARGE with a 40 Hz cut-off (even though the VRM50's are definitely not going to hit 40 Hz, and I'd previously manually set the speakers to "small" with a 60hz front and 80hz rear cutoff).

So - I assume at this point, I'd go in after calibration, manually re-set all speakers to small, and set the desired 60hz-80hz cutoff (playing around to see what sounds best for front/center/rears, which can be set in separate 10hz intervals for each F/R pair and the C).

So what exactly IS the point of auto-calibration if you are changing what the system "thinks" is right? Granted - it does approximate distance from speakers to the prime listening area, but if you then go reset the cutoffs and speaker size, doesn't that nullify the results of the calibration? Or am I overthinking this?

[Doublej]

Note that I amended my response to question 4 which is regarding the phase and LF eq. switches.

IMHO the idea behind auto calibration is this is the manufacturer's approach to providing a push button for getting better sound out of a setup than just connecting everything and turning it on. It's far from perfect.

I don't think changing the speaker size manually after auto calibration should affect the time delays that have been set by the auto calibration but what happens likely depends on the particular AVR. Given that you are increasing the cutoff frequency for speakers that can't reproduce frequencies that low anyway, I don't think you'll notice a difference in sound quality.

I am confident that others here on AudioCirlce including WGH can provide you with a much better answers than mine. You can also head over to AVS Forum for lengthy discussions on these topics including the detailed functioning of your Sony AVR.

[ReggieG]

Thanks ... I belatedly realized that I could select the parameters of the collaboration - including distance, speaker level, and frequency characteristics ... but if I deselect "speaker level" and "frequency characteristics" (one or both), I'm not sure what the calibration is doing. Guess I have to play around a bit more - and yes, asking around more (thanks for the recommendations). Unfortunately, the manual doesn't shed much detail into how the variables play together (for example, if I manually set the speakers and then deselect "speaker level" for calibration, does it leave them at "small" and then try to adjust the "frequency characteristics" that I have set?). I guess mucking around and reading more is the way to go! I appreciate you taking the time to answer. Cheers.