Ported speakers, group delay, and running CBM-170SEs full-range

[tomker]

Hi guys, I'm pretty new to audio and have a couple of questions. Thanks in advance for any thoughts on the subject.

Am I correct in thinking that the sound coming out of a speaker's port is delayed by a wavelength?

If so, wouldn't that "muddle" the sound? And if so, wouldn't the only way to avoid this muddling be to filter out the lower frequencies going to the speaker?

The reason I'm asking is because I currently have a sound bar with a subwoofer. Most of the sound from the subwoofer seems to come from the port. It's definitely impressive (great for explosions!!) but otherwise I don't feel like it's coherent. It definitely seems to muddle the lower frequencies of male speech.

So I have this idea that I want to move away from a subwoofer and get bigger stereo speakers like the CBM-170SEs instead. I'm willing to trade some low-frequency extension for coherency. But the CBM-170SEs are ported and seem to get pretty substantial bass reinforcement from their rear ports so I'm worried that I'll end up with the same problem.

Maybe the only way to get really coherent sound is to get bookshelves, cross them over before they roll off, and get a big expensive sealed subwoofer? I don't want to spend the money or apartment floor space for such a solution though.

Or is my whole train of thought about this misguided? Thanks again for any advice. :)

[DougMac]

Welcome to the forum Tom!

I think the problem you are trying to solve is not as much related to port theory as it is to the application of that theory.

Would you clarify information about your soundbar? I see that some soundbars have a "subwoofer" built in and some have an external subwoofer as part of the package. Which do you have?

You just can't get around the physics of low frequencies and I can't see any way a soundbar, given its size, can have a true subwoofer. It evidently is creating sound near the range of the male human voice, which is higher than frequencies normally handled by a subwoofer.

I think if you replace the soundbar with 170's, you'll experience a marked improvement in sound and intelligability. The 170's have good, clean bass, but they won't rattle the walls. If you're in an apartment, you probably don't want to do that anyway. I suggest getting the 170's and think about a subwoofer later.

How big is your TV? What kind of AVR do you use? Two 170's will do, using the receiver set for phantom center channel. Three, Left/Center/Right would be better. I guess you are not running surround speakers. If you watch a lot of movies, that can make a huge difference.

BTW, I have 170's as side surrounds and they sound great.

[tomker]

...
Would you clarify information about your soundbar? I see that some soundbars have a "subwoofer" built in and some have an external subwoofer as part of the package. Which do you have?

Hi Doug, thanks for the reply. I have a Vizio S4221W which has an external wireless sub that's crossed over at 90Hz. I picked it partially because it gets good reviews and partially for the low crossover frequency (for a sound bar). I wanted to minimize how localizable the sub was, even though I do put it right alongside my TV.

It does "catch" the lower end of some male speech, and when the sub is on, I have the feeling that the sound is simply less clear. Friends of mine have more elaborate sound systems and their subs do not seem to affect the clarity of the sound so I'm thinking the problem is that the output from my sub is out of phase with the output from the sound bar.


How big is your TV? What kind of AVR do you use? Two 170's will do, using the receiver set for phantom center channel. Three, Left/Center/Right would be better. I guess you are not running surround speakers. If you watch a lot of movies, that can make a huge difference.

My TV is not big by today's standards (40") and I don't have an AVR--one of the reasons I bought a sound bar instead of a conventional AVR + passive speakers is because I wanted to minimize the complexity of the system. Of course I love room-shaking bass and big explosions (who doesn't?) but would rather try to get that from some nicer, bigger stereo speakers vs. adding extra components. Ideally I think I would like some Sierra Towers but $2k is a big mental hurdle considering my last audio purchase was 1/10th as much (for the sound bar). :)

[natetg57]

The 170s won't have any clarity issues if properly placed. They do need to be spaced a bit from the wall especially if playing them full range. Probably 6-10 inches would suffice. If you want to place speakers directly on the wall them the HTM-200s would be an excellent choice. They don't go as deep so you'll want a subwoofer paired with them. A good quality one, probably not what comes with a sound bar.

[tomker]

The 170s won't have any clarity issues if properly placed. They do need to be spaced a bit from the wall especially if playing them full range. Probably 6-10 inches would suffice. If you want to place speakers directly on the wall them the HTM-200s would be an excellent choice. They don't go as deep so you'll want a subwoofer paired with them. A good quality one, probably not what comes with a sound bar.

Thanks for the feedback. Is there a good way to find people in my area (near Seattle) with CBM-170s that I might audition?