Setup: Have I done it correctly?

[thm655321]

First as a newbie to all this let me say that this forum is a goldmine and the posts together with the REW help files answered most of my questions.

I have a combined home theater and audio system. My main focus is audio with movies/TV second. My main speakers are the Apogee Mini-Grand system which consists of Apogee Stage ribbon speakers each sitting on a dual driver ported sub in a bi-amped arrangement. I also have a Velodyne HGS-12, so in effect I have three subs in the system. The Apogee subs go fairly deep, but not with the same weight/authority as the HGS-12. The subs are set up as follows: Each L/R channel of my preamp is fed to a Paradigm X-30 crossover which then feed the Apogee Stages with a high pass 80Hz signal. The Apogee subs are fed the L/R subwoofer signal from the X-30s low pass crossed at 80Hz. The Velodyne is also fed the same L/R signals from the X-30s that are sent to the Apogee subs (each X-30 has two sub outputs). I bought the FBQ 2496 to EQ the Velodyne in an effort to better bass frequency response for audio (any improvement to home theater would be strictly a bonus).

In setting it up, I plugged the FBQ between the X-30s and the Velodyne such that the FBQ is being fed both the left sub and right sub stereo signals. I used AVIA to set the levels of all three subs (I think) correctly. I did this for each speaker by first matching the sub output of the Apogee sub to the speaker, then matching the output of the Velodyne to the Apogee sub, and then with the Velodyne and Apogee sub playing together matching the combined output of the subs with the Apogee speaker by using the sub volume control on the X-30 (which attenuates both subs at the same time in this arrangement).

Using REW, I did a room response for each speaker and the Velodyne together (i.e., I did the frequency tests using the right speaker/sub+Velodyne on their own and then using the left speaker/sub+Velodyne on their own). My aim was to get the flattest frequency response possible for each channel, not to generate a house curve or anything fancy. I got the response as flat as I could and ended up with 5 filters on the left channel and 3 on the right channel. I fed the filters to the FBQ using REW over the MIDI connection.

The result? Bass/LFE for movies is still very good, if not better. For music the soundstage appears to have opened up and the bass is more clearly defined. For instance, when I press the FBQ's bypass button the bass is not as defined, however I would not call it a dramatic difference.

A few questions for the experts:

1) Does the way I did my set up of the subs and FBQ make sense or is there a better way? For instance, should I have done the sweeps with both speakers playing at the same time to adjust for a combined frequency response?

2) I did not adjust the input level of the FBQ at all. When playing movies with lots of LFE/bass I only get about 4 lights max to show up on either L/R LED output meter. Should I adjust the input level? If so, at what stage should it be adjusted (e.g., prior to doing the AVIA calibration)?

Any advice would be appreciated, thanks.

THM

[brucek]

Does the way I did my set up of the subs and FBQ make sense or is there a better way? For instance, should I have done the sweeps with both speakers playing at the same time to adjust for a combined frequency response?

I do think it makes sense, but since you're feeding the Velo sub a different voltage waveform on its right channel compared to its left channel, I wonder if it wouldn't be wise to see how it all looks in REW when the three subs along with the ribbons play in concert. There might be some filter adjustments you need to do...

Should I adjust the input level? If so, at what stage should it be adjusted (e.g., prior to doing the AVIA calibration)?

Adjusting the input level usually just involves tweaking the subwoofer trim output on your processor. In your case you have the X-30 with its rather large gain capablities connected before the FBQ. How do you propose to increase the level of the FBQ? If you turn the X-30 up, the three subs and high passed output will increase in a wholesale fashion. What have you accomplished? The X-30 is acting as your bass manager and has removed your capability of discretely controlling what is sent to the FBQ, has it not? Not a big deal though - you are getting 4 LEDS..

brucek

[thm655321]

Thanks.

You are right of course on the input level. I guess I was thinking about input sensitivity/gain of the FBQ but if it has no adjustment for that then I guess I am okay.

THM

[thm655321]

Fooling around with the FBQ some more and I realize that the input level coming out of the X-30s is probably way to low as even at the loudest listening levels I only get a few bars on the FBQ's input meter. When I connect the FBQ directly to secondary full signal preamp outs I get good input levels without clipping. Using the preamp secondary outs as opposed to the X-30 outs will require readjusting subwoofer volume levels and using the Velodyne's crossover, but no biggie.

Do you think this is a better way to go? Thanks.

THM

[brucek]

Using the preamp secondary outs as opposed to the X-30 outs will require readjusting subwoofer volume levels and using the Velodyne's crossover

I would guess that the X-30 is not set to a unity gain volume since the preamp outputs are higher (as evidenced by the FBQ being driven harder when connected directly to the preamp). I suppose you could simply turn up the X-30 volume until the FBQ was correctly driven and then turn down the volume (if possible) on the Apogee mains and subs?

If not, I don't see much difference in hooking the Velo to the preamp directly. In fact it may give you a bit more control over the crossover settings, where before the X30 determined all three subs crossover.

By the way, just for your information, the -46dB poistion on the X30 dial is 1:1 unity.

brucek

[thm655321]

I think the difference may be accounted for by the fact that the signal coming from the X-30s is crossed at 80Hz while the signal from the preamp is full range.

On the unity gain point, that information is very useful. I have not seen that spec before (perhaps it is in the manual but I can't recall that) I take it by unity gain you mean the usual definition of input equals output? If so, perhaps what I should do is set the X-30s at -46db (which is below what they are set at even with the Velodyne in the system adding bass) and increase the level on the Velodyne to then match the main speakers. Does that seem like a worthwhile approach?

THM

[brucek]

have not seen that spec before (perhaps it is in the manual but I can't recall that

No, its not in the manual. I bench tested the X-30 when I got mine a few years ago to check the gain and the unity point and a few other crossover points. The dial lettering is quite poor, but the unit is very nice.

By unity I mean, I simply found the point where the voltage out equalled the voltage in (when not in the crossover region)
I also did a quick response of the unit with the crossover dial at minimum and maximum and the 9 oclock position. I wanted to be sure when I dialed it to max, that it would be outside the crossover area of my processors bass management. Then when I wanted to use the crossover for bass management of about 35Hz, I needed to find that dial position. I settled on about the 9 oclock position.

I attach the excel file (for what it's worth) if you want it.

Does that seem like a worthwhile approach?

Yeah, then I would think the level from the preamp would equal the level coming from the X-30 at frequencies below the crossover..

brucek

[thm655321]

Turns out I was mistaken and the x-30 level is much lower than 46db. Looks like I will have to rethink this.

Thanks very much for the excell file, very very useful.

THM