Confused about connecting subwoofer (1 Viewer)

[dave95sps]

This question is similar to the one posted by Jonathan. My problem is with connecting my subwoofer to the receiver. I have a Sony STR-DE545 5.1 surround system. Outputs on back are for L&R front, L&R rear, center, all with red/black spring clips to connect speaker wires. Also on receiver back is a circular output jack which looks like a mono RCA connector marked "subwoofer".

My speaker system is a Bose Acoustimass. On the rear of the Acoustimass subwoofer, the speaker connections are for left and right channel only (input & output), with no other inputs for the subwoofer connection from the RCA jack on rear of receiver. I get some bass sound from the Acoustimass, but not much.

At present, I have the front L&R speakers going to the subwoofer, then to their respective front L&R speakers from subwoofer. The center speaker is wired directly from the center speaker output on the receiver to the center speaker. The two rear speakers are both wired directly from receiver to their respective speakers.

The audio test on the receiver scans each channel and makes a audible sound on each speaker except the subwoofer. The receiver display shows the test begins with the subwoofer (no sound) then to front left, center, front right, rear right, and rear left all WITH sound from their respective speaker.

Any suggestions on how to get the Acoustimass subwoofer to project decent bass would be appreciated.

Thanks,
Dave

 

[Stephen Tu]

You'll get more bass with proper receiver configuration. But to get great bass you'd need to upgrade to a bigger, powered sub + speaker system.

 

[MaxL]

1 - catch bass in local lake. not too big as they won't fit in easily.

2 - insert bass into subwoofer.

3 - light fuse of 1/4 stick of dynamite or similar.

4 - insert lit explosive into subwoofer.

5 - run.

6 - see, hear and feel decent bass projected.

-OR-

drop from a height significant enough to produce decent boom but not so high as to be too far away to hear said boom. i'm guessing 15 - 20 feet would be ideal, especially in a gym on a hardwood basketball court, off the bleachers. but again, get ready to run because i don't think they're gonna like what it does to the court.

 

[dave95sps]

Stephen,
Thank you for the information. I will check that out.
Dave

 

[Robert_J]

The Acoustimass box isn't a true sub. It's more of a bass module that fills in the low end of the spectrum that the tiny cube speakers can't handle.

-Robert

 

[JohnRice]

Robert is correct. If you are intent on keeping the Bose, you would run them like regular speakers the way you have them hooked up now, but with the speakers all set to "Small", then get an actual subwoofer and connect it to the subwoofer output.

 

[chuckg]

Max! that was too funny. I always imagine Groucho Marx saying "ah, but first you have to get the bass into the loudspeaker" and waggling his cigar.

 

[dave95sps]

Thanks for your help everyone. I made the setting changes...front left and right speakers to "large", and the others to "small". Also changed the subwoofer setting from "yes" to "NO". The changes make a big difference in bass....and making me curious to see just how a dedicated subwoofer might sound...hmmmm.

Dave

 

[Jeff Gatie]

I wouldn't worry about setting the speakers to "Small", I'm pretty sure the "Bass Module" has a low-pass filter that strips anything below 40Hz. Probably the most expensive item in the box at $9.99 retail, but elimination of all lower bass ranges which could expose the weakness of the design is worth it.

 

[Stephen Tu]

To be clear, with *just* the speakers he has now, he should definitely set the front speakers to *large*! Otherwise the system will try to redirect bass to a non-existent sub on the subwoofer out, and he'll get very little bass at all below the crossover point. Which is the problem he is likely complaining about now. Sure the Bose can't do below 40 hz well, but you don't want to also get rid of 40-100hz!

*If* he gets a bigger powered true sub to get better bass, *then* he can set his fronts to small and subwoofer "yes".

 

[1122334]

Yep, same problem I had. Basically, in simplest terms, the subwoofer must be powered somehow. The mono RCA cable which I believe is actually a digital coaxial cable, does not power anything. Basically, your system and mine, are designed to deal with powered subwoofers only. That is, a subwoofer that plugs into the wall and then can be plugged in to the amp/audio receiver a through the mono RCA input.

As for me, I have temporariy hooked up my sub to a main speaker terminal since they get a lot of bass. In the meantime, I'm searching for a powered subwoofer. I'm not sure if your system can use only two main speakers or 4 like mine, (Main speakers A and main speakers B) but what I did was just set up my mains to main speakers A and then plug the sub into main speakers B.

 

[LanceJ]

Personally speaking, I would be extra careful when using this system when set up like this.

Based on what I've seen, Bose's cubes are all made to be connected to a Bose bass box which includes inputs/outputs for ALL the cubes used in an HT system. That's because the bass box includes a filter for each cube that's constructed to delete all bass below a specific frequency. But most receivers in my experience have user-adjustable filters that go only as high as 150Hz.....but according to some reviews I've read over the years, it looks like the cubes' filters are set up at @200Hz. In other words, your receiver may not be able to prevent enough bass from reaching those tiny 2.5" drivers in the cubes, which IMO increases the risk of them being burned-out, and if not that, causing unwanted distortion.

I would contact Bose to see what they say.

 

[Stephen Tu]

Actually, not the same problem you had. Your problem was a passive unpowered sub, with no crossover filters. Dave's bass module is powered, and has filters to direct the sound to the bass driver/micro-satellites appropriately. His issue is that his system only takes "speaker level" inputs, not "line level", and the main thing in his case is receiver configuration. Your situation is somewhat worse, because you are lacking both power and the filters.

The commonalities here are only no line-level input, and that both are more bass modules than true subwoofers.

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Agree with LanceJ about the crossover; connect through the bass module if possible, instead of directly to receiver, set such speakers to large. It'll crossover higher than what the receiver does which is desirable with the small driver. What's the model/series # of the speakers?