Trying to figure out how to get this less boomy...

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Ok, so I started from a Klipsch Promedia 2.1 system -- though the only recognizable components are the control module and the amplifier (which isn't even visible normally.) I've changed the mid-range drivers among numerous other things such that it's no longer really even the same system. I'm extremely happy with the mids and highs from the system now, but I'm still having trouble with the lows. In particular, I'm sick of getting boomy sound and want a relatively flat bass response for music listening (I could not care less if it sounds bad by some people's standards in movies or something, music is the key here. For that matter, I don't really even watch movies anymore...)

The first thing I did was to try to switch to a properly sealed enclosure. I built a new box using 3/4" MDF. At the time I had no idea really about all of this, so I started out with an enclosure that would have the same internal volume as the original (but then the original was vented, so this perhaps wasn't the brightest idea.) This did seem to help a bit though as the original sound was just awful. I next tried getting a different driver. Due to rather severe budget limitations I decided to try the Dayton Audio DC160S-8 6.5" driver. It does appear to be better than the original at least, but still a bit boomy in some things with a lot of a bass guitar or certain drums.
 
download the freeware WINisd pro.
Look at what a sealed Qbox=0.7 response looks like.
Now compare your drivers and enclosures to the Q=0.7 response.

If your Q>0.7, then that will give bass emphasis to a narrow range of bass frequencies.
The higher the Q the worse this problem gets. Many manufacturers design in a high Q to give bass emphasis instead of bass extension. They are terrible to listen to.

Q<0.7 can sound a bit bass light, (the response rolls off very gently and early).
I was advised to look for a vented enclosure tuning that very roughly copied a Bessel function (Q~0.5). This when in room produced deep strong bass and did not sound light at all. More importantly, it did not have bass boom, nor one note bass, nor that male voice with bass emphasis.
 

Attachments

  • Dayton-DC160S-8.JPG
    Dayton-DC160S-8.JPG
    463.7 KB · Views: 380
Administrator
Joined 2004
Paid Member
First things first. Pack the box full of insulation and try it again. If you use fiberglass or rock wool it doesn't hurt to have a piece of cheesecloth or an old pillow slip to cover the back of the driver first. Also, your .1 amplifier likely has a bass boost feature that you might want to override if the insulation trick doesn't work. This may require help from someone with a schematic and a little experience.
 
Perhaps I described it wrong. I'm referring to the way that at times when there's a lot of bass it sort of distorts. Usually it's only really excessive things like videos with explosions or etc and even then usually they have to go too far. Very rarely does it happen in music, but, needless to say, it's quite annoying when it does. It is true that the original system did it too though, and it was vented, so I'm not entirely sure whether or not this is the solution. In the end, the problem may just be that the driver itself really isn't all that great for real bass since it is, after all, a mere 6.5" driver. Well, clipping isn't the best word. It's not actually clipping like being driven too far to the point of threatening to tear up so much as it just distorts. (I'm not really sure how else to describe it though as "just distorts" isn't really a very good description.)

Most importantly though, I've a bit of a budget problem atm. Namely, I don't really have much to spare at all. That means I can't really buy enclosures or that sort of thing unless they're pretty cheap (read crap.) I'd be getting something that's not even MDF probably. Anything I do beyond something really cheap (such as the vent pipes which really aren't all that much even on Parts-Express) is probably going to have to be done myself. However, I don't think I can build another enclosure at this point (not only am I out of wood -- though I can get more if I need to -- it ends up requiring quite a lot of time to actually do and atm I don't think I have that kind of time.) I can build another enclosure if it is just absolutely necessary, but in other words I'd rather find a way to make this current one (which really should already be more than it needs) work if at all possible. (And for the record btw, I still have the old smaller enclosure that I built to have roughly the same internal volume as the original except being made of MDF versus that being LDF and being a sealed enclosure versus that being vented if it would work any better or anything, but it is rather small compared to what I have now.)

Oh, and no, it's not the room. Just how bad would your room have to be that it would actually affect the subwoofer driver itself?
First things first. Pack the box full of insulation and try it again.
Sorry, I know I tend to post very long posts. I did say that I have filled it with fiberglass. The walls of the enclosure are also lined with 1" Sonic Barrier.

Also, your .1 amplifier likely has a bass boost feature that you might want to override if the insulation trick doesn't work. This may require help from someone with a schematic and a little experience.
And who might that be? Lol. Does it have such a "feature" though? It seems to me like there's no need for a bass boost when you have an actual subwoofer level control right on the main module. If you want more bass you just turn it up, right? Regardless, I don't know of anyone who could provide such details. I do wonder about this though as it could perhaps explain the issue.
 
Last edited:
Right, but then the question is, is there any way to get it able to handle just the amounts used in things like music, which don't go nearly as low (that 45Hz minimum one person mentioned sounds probably about right) or nearly as loud as, say, movies? It can't produce truly low frequencies evenly, but what about normal stuff for music? It already goes lower than originally expected since it was built with movies and such in mind.

On this subject though, I wonder if anyone might have any clue if the amplifier even could handle anything bigger? It might be a while before I could buy a bigger driver, but it's not impossible. Replacing the amp AND driver at the same time though gets a lot more tricky money-wise.
 
I don't think you are going to get any further with the 6.5 inch driver, it's just too small.
For really serious bass, but I still wonder about the bass that's in normal music (btw, I'm not a bass head and don't listen to any of those trances or whatever. Much of my music does have more bass than is "natural" so to speak, but it's still a lot less than many things out there.) I'm still kind of wondering if maybe all it really needs is more of a rolloff of the really low bass frequencies or something since it's really much higher frequencies that I generally care the most about anyway.

The amp should be fine driving a bigger speaker. Generally bigger speakers are easier to drive.
Really now? I would have thought that a larger driver with more mass and such would require more energy to physically move. Is it just that they are more efficient at bass frequencies or something then? If it could handle a larger driver, my apx 1ft^3 enclosure could definitely accommodate a somewhat larger driver at least, surely (after all, it was meant to be more than should be necessary for my current driver.) And I really would rather stay sealed if I reasonably could do so as it's the least distortive way to go without getting more complicated than I know how (hence this thread's existence in the first place since I really wasn't sure how best to go vented.) So then what should I do, bearing in mind that I want a mostly balanced sound for music (and don't care about movies and such -- explosions can sound boring for all that I really care. Even in PC games I still prefer a more balanced sound anyway.) Would an 8" driver be sufficient for the task? If that thing I read is correct and 45Hz is the lowest that really would matter from music, I don't care much about the lower frequencies. I just don't want it to distort when playing music is all.
 
Hmm. Realistically speaking, how might this one do then? Dayton SD270-88 10" Shielded DVC Subwoofer | Parts-Express.com Great price and I see one reviewer saying that they get good results down to 40Hz out of it. Apparently the recommended enclosure size is just about the same as what I ended up with (though I see reviewers saying that bigger is better unsurprisingly enough. Well, I'll not be taking the fiberglass out, so that should help a little bit at least.) Do you think the little amp in this thing that was originally built for that probably dirt cheap 6.5" subwoofer driver that came with the system could handle this (bearing in mind that I'm going to have it turned down pretty low since I just want it to work with the music, not shake the building)?
 
It's no good for your intended use.

How many ohms is the stock (sub)woofer ?

You need a driver that is the same impedence to get the maximum power out of the amp.

The amp puts out only 50W at 7% distortion , according to the "repair link" posted previously.

So in reality, you are probably looking at like 30 watts or so at a reasonable distortion spec. Just a guess.

Get the highest efficiency 12" driver you can find that is the proper impedence. This will relieve the bass amp from being overdriven , as the driver will require less power to achieve good output levels.

This is what you need to achieve the goal with your specific needs in mind.

Look at Eminence Alpha , Goldwood PA drivers, etc. High efficiency, higher Qts, low cost. These are 8 ohm units , you may need a 4 ohm driver. I would have to look around , as none jump to mind.

Roughly 40hz tuning with a simple sealed cabinet. A piece of cake.

Find out how many ohms the stock woofer is and let me know, then I can recommend a suitable driver.

Just my opinion.


..............................Blake
 
I'm pretty sure the stock driver is 8 ohms. The DMM tested it at 6.something anyway, and as far as I know the nominal impedance is higher than the DC resistance, right? There's not much else to go on as I don't really see much on it to identify it by (and it definitely doesn't say anything like impedance on the driver itself.) I'll admit that, when buying this one, I assumed it was 8 ohms. IMO the amp seems to be able to drive this driver as much as I need out of it with plenty of room to spare at the levels I'm using (remember, I now have it well below the recommended mark which in turn is far below the full volume level.)

A 12" driver seems a bit overkill though. Is that really needed for music? (Excluding maybe hip-hop and some trance or whatever, neither of which I ever listen to.) Also, I couldn't help but to notice that one person said they were using that 10" driver with a 20 WPC amp. Even assuming it's bridged, that would mean 40 watts max (and, as you say, realistically most are less than what they say.) To make matters worse, I wonder if there's even any way this same enclosure could accommodate a 12" driver. Not only do I question whether the internal volume would be enough, but, how well would a 12" driver fit even? The wood itself is basically 12x12. If not, that would mean I'd have to also buy more wood (I've finished off the board I originally bought between two subwoofer enclosure attempts, a "portable" speaker build of which I made a second after it worked out surprisingly well, and a few odds and ends and failed cuts) and build yet another enclosure (which I swear takes just about a whole day somehow, though I can't figure out how it's taking quite so long. It's probably not helping that, while I have good equipment for all of this, it's still not ideal by a long shot. At least the saws and rotary tool I have available aren't bad, but I guess I need a scroll saw or something and one of those expensive metal guides that make cutting circles so much easier.)
 
Er, bad link I think. I can't read German, but I'm guessing that Pyle doesn't make drivers named Firefox. d-:

Anyway, I can't afford a $70 driver right now. And two of them is just not going to happen. I realize of course that cheap components yield cheap results, but it's all I can do right now. Besides, would that truly do any better at music? Again, I really don't need it to rock the building, produce 20Hz, or etc. My goal is a much more subdued amount of bass than what people normally go for -- ideally the total output of the system should at least vaguely resemble a flat line across the spectrum (though of course in real life that's not going to happen with this system no matter what drivers I use.) Regardless, all I can do right now is make do as best as possible with the budget I have. (Of course, you might guess that this is part of why I'm here now with a ridiculously modified cheap low end system rather than having just simply started from a much higher quality system by a brand that focuses more on music rather than movies and such.)
 
Last edited:
Ex-Moderator R.I.P.
Joined 2005
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.