Can't get bass from speakers (1 Viewer)

[dustinSkater]

I think something is wrong with my setup here. My problem is that I can't get much bass from my three speakers. They are the PSB Image C60 and S50. The T55's have a damage claim on them so those will eventually be the fronts. But right now I just have the surrounds hooked up to the front connections even though they are mounted on the wall behind me. And the center is hooked up too. So now what I'm wondering is why I can't get much bass from the front speaker. My receiver is Onkyo TX-SR703. I have the settings as subwoofer off and the fronts and center at full-band. Sound of course comes out of them all but I just have the surrounds turned off to make it a 3.1 setup. So I was wondering if there is something I'm missing because I think the speakers should be producing more bass than they are.

 

[LanceJ]

From the "bipolar" link on PSB's page for their S50 bipolar surround speaker (emphasis is mine):

Just like with a conventional pair of speakers that are (usually accidently) wired out of phase, this will result in basically no low bass being heard.

 

[John Garcia]

Not to mention they are -3dB at 65Hz.

 

[dustinSkater]

Ok. I don't know a whole lot about this, my area of expertise is computers, so if these questions are stupid, sorry.

So are you saying that I have the speakers wired wrong or they are supposed to be like that. Also what about the center, am I missing something with that? I checked the wiring on that and that was correct. Or do these just not produce the amount of bass I think they should have - and that would be...able to feel it when you put your hand in front of it.

 

[John Garcia]

-3dB at 65Hz means the S50s do not have a tremendous amount of bass, not the kind you will really feel from a distance anyway. The center is -3dB @ 50Hz, which may give you a little more oomph, but not a ton and with it being only one speaker, it may not be enough. The speakers I run are all -3dB at 55Hz, and they produce respectable bass, but it is nowhere near that of a speaker with a larger surface area.

No, the speakers aren't wired wrong, they are intentionally wired like that, and that can affect the bass you hear from them, especially if they are not placed properly relative to your listening position.

Do you have a large room? Are the speakers set to large? The way you have it hooked up too could be a definite problem.

 

[dustinSkater]

Alright thanks or clearing that up. My room is tiny, somewhere around 10' x 11'. My sub is a 20-39PC+ (way too big I know) so when that's going bass is not really a problem. It's just at night when everyone is a sleep it is. But ok I just that they would have produced more bass that I thought, but then what about the T55's would that be? They are ±3dB at 32Hz would that be what I'm hoping? And on the subject of if they are placed correctly, I don't think they are. They're mounted in the corners of the room. The right rear is about 4' away from my head and the left rear is about 7' from my head. I'm not sure if they are facing the right way either. The way the speakers face is that they are parallel to the wall. Two of them face eachother and the other two face towards the tv. We really can't do much with them but it really isn't that important to me. I havn't used any calibration yet because I've been waiting since early September for UPS to look at the two damaged fronts.

Thanks for your help too.

 

[LanceJ]

John: even if they were flat all the way down to 20Hz, speakers that are literally right next to each other (like the drivers in these surround speakers) and wired out-of-phase won't have any bass at all below @150Hz. So it wouldn't matter where each individual surround speaker is placed.

The only reason the higher frequencies remain intact - approximately above 150Hz - is because now they have become directional and so never come into contact with their "anti" twin soundwaves emanating from the other set of drivers.

I'll pretty much guarantee these can also cause problems elsewhere in the house, depending on how loud they are turned up of course. My Bostons get down to 42Hz (+/-3dB) and I pissed off people all the time in my dorm (not on purpose.....most of the time anyway ). The bass of most music lives in these frequency regions, including a lot of movie effects.

 

[John Garcia]

It would be rather silly of them to create a bipole that cancelled itself out, wouldn't it? Might as well make it a monopole then...otherwise the midbass drivers serve no purpose. The drivers appear to be at enough of an angle (looks like about 45deg actually) from one another that they will not cancel each other out. All bipoles are this way, regardless of the alignment of the drivers.

 

[LanceJ]

That is what a bipolar design is used for. The area between the drivers where there is no output because of the cancellation AND the directionality of the drivers (particularly the tweeter) - i.e. the "null" zone - is the same area that is suppsoed to be aimed at the listening area. This way the listeners don't hear any sounds directly from the speaker. Instead what they eventually hear from those two sets of drivers is their sounds bounced off the rear and front walls - this is what produces that gauzy/cloudy sound this design is known for.

BTW: this is why planar speakers i.e. electrostatics (Martin-Logan, etc) and dynamic types (Magnepans, etc) have so little bass relative to conventional loudspeaker designs. And I'm speaking of "pure" planars, those with no built-in cone woofers to supplement the low end.

Dipolar designs - whose drivers are wired *in* phase - on the other hand ARE meant to fire sound in the direction of the listeners in addition to the rear and front walls.



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As an off-topic aside: this bouncing-off-the-wall effect is why these types of speakers are not recommended for playback of surround music.

Surround music mixers use direct-radiating/monopole speakers as monitors to help them create the sound field they & the artist desire, so if di/bipolars are used on the playback end, that soundfield will be pretty much shredded to pieces. That's because a music surround soundfield does not just exist behind the listener's head: the rears and the front speakers are used together to create a complete music soundfield, a "bubble of sound" if you will. But if one is using speakers placed directly to the side of the listener (5.1 music mixers have their monitors behind them.......and to the side) and utilizing speakers that spray sound pretty much everywhere, that bubble never has a chance of being created.

This is another reason I think some people don't like the way surround music sounds i.e. they are not hearing it played back correctly. And personally, I also like to listen to movies with monopoles since IMO this more faithfully recreates the effects the director wants me to hear.

 

[John Garcia]

I see what you're saying, but he said they aren't placed correctly, meaning he isn't in the "sweet" null spot of these speakers.

 

[Cees Alons]

Nor does he have to be. Like Lance said, below 150 Hz, the two speakers will compensate each other out.

Below 150Hz the wavelength of the produced sound will start to be as big as, or bigger than, the dimensions of the room. So it no longer matters where you're situated: the whole room will have cancelled out bass (the bass frequencies from each of pair of those speakers only, of course ).


Cees

 

[John Garcia]

I really don't see the benefit then? (never been a fan of bi/dipoles anyway) How can they have a -3dB of 65Hz, yet cancel each other out below 150Hz?

 

[LanceJ]

This article may answer that question (though PSB seems like a cool company so I think they may be just using a specific test system of their own).

 

[Jeff Gatie]

Because they are out of phase through parts of their soundfield. This helps when mounted as surrounds, as the speakers are denoted as L or R and must be mounted this way in order for the soundfield(s) to play correctly (the bouncing off the wall, indirect effect mentioned above). This is often useful in older Pro-Logic setups that used a more blended rather than directional surround, because of the mono surround limitation. Used as mains, this out of phase configuration is terrible and causes the above dropoff after 150Hz.

 

[John Garcia]

That would suggest they are not testing it in bipole mode, without cancellation of the out of phase drivers present.

 

[Cees Alons]

Those tests are almost always done with a microphone almost in the cone of the speaker, if you know what I mean.

They were good for surrounds in the Dolby Pro-Logic system, because according to the specs, DPL didn't have lower frequencies in the surrounds.


Cees

 

[John Garcia]

I expect something like that from DefTech, but not PSB.

 

[dustinSkater]

So are you saying I should have gotten Image B25 Monitor's, because it sounds like I should have.

 

[LanceJ]

If you like the sound of bipolar surround speakers, then that is all that matters. Just be aware that for them to produce their special sound correctly, they must be placed in very specific locations in the listening room (this is another reason I personally don't much like them).

 

[andySu]

dustinSkater

I wouldn’t touch a dipolar or bipolar with a ten foot barge pole! I have tried those rotten loudspeakers and there a CON! There over priced and surrounds should be placed in the room in a (hoarse shoe configuration) with multiples down the sidewalls and on the rear wall! Much like what I have done, and there is no discrepancy what so ever in the reproduction of the surrounds, just pure cinema surround within a small room!

Mate I would dumb those donkey surround loudspeakers on the Ebay like a bad habit! Or take them straight back to the shop and get your flipping money back, and get yourself an array of good quality bookshelf types at an affordable cost, believe me there are plenty out there!