[aharami]

I bought a pair of SW-12B and a SA-1 amp from Danny a while ago.  I finally got around to finishing the enclosures and fired it up last night.  But I find that the subs arent loud enough when using the Line-In Input.

I built two separate enclosures for the subs, and the amp sits in its own box, all connected via 12 AWG speaker wire.  The internal dimensions of the enclosures are 13.5"x15.5"x11.75", and with braces and woofer vol (.09 cu ft), internal volume comes out to slightly under 1.3 cu ft.  I stuffed about 10-15 oz of polyfill inside each enclosure.

Im connecting the SA-1 amp via a digital RG6 subwoofer cable from the LFE output from my Onkyo TX-SR876 AVR.  I set the AVR's crossover to 80 Hz (its lowest). 

Connecting the SA-1 via its LFE input bypasses the amp's low pass shaping circuitry and although I get decent output via LFE, I find the subs sounding too boomy and not low enough.  So i hooked up the subwoofer cable to one of the line-in inputs and although that generates a much lower output, it is not loud at all. 

Case in point:  My AVR's speaker settings are set to -1.5db for the fronts and with my older sub, I had it set to -5db.  With the SA-1 hooked up via its LFE input, I can set my AVR's LFE to -4db, SA-1's volume to about half way and get decently loud output from the SW-12Bs.  Except that the subs sound waaay too boomy this way.

With the SA-1 hooked up via one of it's Line-in input, I have to set my AVR's LFE setting to +12b (max) and turn up the volume on the SA-1 all the way to get decent loudness from the subs.  At halfway volume, there isnt any audible output from the SW-12Bs. 

I's definitely prefer to use the Line-In instead of the LFE as the subs go MUCH lower with the Line In.  but loudness is a matter of concern since I have no room to expand since the AVR and amp are maxed out in the Line-In setting.  Is this happeneing because Im utilizing only one of the line in inputs?  Will it help if I get a Y splitter and connect my subwoofer cable to both L and R inputs of the SA-1?  Or am I just expecting too much from this setup?

I provided all the details I could think of, and would like to know what the more knowledgeable people here think might be the cause of this problem.  I'm open to any suggestions.

Thanks

[Danny Richie]

Im connecting the SA-1 amp via a digital RG6 subwoofer cable

Digital cable? I don't know anything about that particular cable, but you are not using that cable for a digital signal. That is an analog signal.

And yes, to get good extension you need to be using the left or right input.

Sounds like you have low signal strength or low output levels being sent to the amp via that connection.

[aharami]

Danny, I'm using one of these, which is meant to be used as a subwoofer cable.

[aharami]

I will also try hooking it up to my other AVR tonight to see if there's any change in output levels.  But I really dont think that the 876 is putting out low signal strength via its LFE output.

[HAL]

You might want to test the sub and cables without the AVR.   If you turn down the volume level on the subs and connect the line level inputs to a CD or DVD player, do you get enough signal as you turn up the sub level?  Make sure you use a CD with known bass output as that is all you will get. 

Just a thought.

[Danny Richie]

Good thinking HAL. Go right into it from your CD player.

[aharami]

thats a good suggestion.  I'll try that out when I get home.

[aharami]

definitely a case of my lack of knowledge.  I hooked it up straight from my BRD player and it is much louder.  Im amazed by how low these subs will go!  I did notice that using a Y splitter and utilizing both Line in inputs makes a noticeable difference in loudness. 

Now onto the avsforums to figure out what settings I need to change in my AVR to get the subs playing properly.  Thanks Hal and Danny for the quick responses!

[BrianH]

Something to try:

Before running Audyssey, set these on the sub:

    * the Low Level Filter Bypass to Out (= Filter Bypassed), the filter is opened wide to allow the optimum performance from processor.
    * the Frequency Contour to Max (120Hz)

After: in the receiver, adjust the LPF of LFE to 120 and check that the LFE trim level is not at -15dB or +12dB.

Brian

[aharami]

good suggestions, thanks.  I will keep those in mind when I rerun Audyssey.
The SA-1 doesn't have a low filter bypass switch, but I will set the frequency knob to 125 Hz.  I'm assuming volume should be around halfway when calibrating for Audyssey?