Speakers. Can I do this???

[Ryan Sparreboom]

I have a decent (not great but decent) home theater in my basement. I will be building a new cabinet and t.v mount and want to attach the main speakers to the "backdrop" beside the t.v.

Currently I have a decent set of main speakers, they are floor standing and have two 5.5" drivers, a 1 " tweeter in between them, and an 8" sub at the bottom. But I don't like the enclosures, and don't like the fact that they are floor standing.
I was thinking of getting rid of these speaker enclosures, and building my own smaller ones with 1/2" MDF, veneered with real wood and finished nice. I would use the electronic components (speakers, cross-overs) from the existing speakers (cause there's nothin wrong with them) except GET RID of the 8" subwoofer and it's required cross over.

The new encloseres would be much smaller (only housing the 5.5" and tweeter) and I could then mount it as I want it.

Can I do this or am I messing with something that shouldn't be messed with?

[Steve knight]

the sound will change. depending on the quality of the speakers and how well they where designed it may or may not make a difference. but the size and shape are fairly critical for good sound.

[Ryan Sparreboom]

I understand the sound may change. But I was thinking that most of the space in the tower was required for the sub. Eliminating the sub, I should be able to make the enclosure alot smaller right?
Obviously there is no way to figure out the exact dimensions for the optimal size enclosure for the remaining speakers, so I'll just have to build it the size I want it and try it out I guess.

[Jeff Bratt]

Making the changes you have proposed will change the sound - a lot. The speakers, crossover network, and enclosure are all designed and tuned to work together. Leaving out half of the drivers (unless the 8" is a passive radiator) might even lower the impedance enough to possibly damage the amplifier. All these changes together is asking for trouble.

The woodworking to build inexpensive, rectangular speaker enclosures is fairly easy - but that is the least of your worries... if you really want to change things, at least search for some speaker design software or other information.

[Ryan Sparreboom]

That sounds like trouble. I definitely don't want to damage my amp (I have a nice Marantz).
How do I know if the woofer is a passive radiator? If it is then would it be safe to make the changes?

[John Twesten IV]

There is some good information and parts on this site if you decide to make the new enclosure.

http://www.partsexpress.com/speaker-building.cfm

http://www.partsexpress.com/projects...ojectindex.cfm

[Jeff Craven]

I understand the sound may change. But I was thinking that most of the space in the tower was required for the sub. Eliminating the sub, I should be able to make the enclosure alot smaller right?
Obviously there is no way to figure out the exact dimensions for the optimal size enclosure for the remaining speakers, so I'll just have to build it the size I want it and try it out I guess.

The volume inside the enclosure is tuned to work with the speakers. If you can match the volume of the old enclosure, you might get acceptable results.

A passive radiator doesn't have a magnet, so if you unscrew it and don't find any wires going to it, then it is passive. If there is a big port for the subwoofer, then it probably isn't passive. If the smaller drivers are tuned to work with a passive subwoofer, then it will be tough to get acceptable results without it.

To get good acoustical results, you need to know the specs of the driver and match the specs of the enclosure, but you probably won't be able to get specs on the drivers in a manufactured speaker.

So what are the floor standing speakers? Have you pulled the drivers and looked inside the enclosure?

<-- also has Marantz

[Steve knight]

I have a set of speakers I am making for a custom speaker maker. these have large cabinets but only 6" woofers.

[Justin Leiwig]

As long as you maintain the same airspace for the drivers and they have a seperate cross over for just the mains and not the subs you will be fine. I would hazard a guess however that if you spend the time and remove the 8" sub you will loose a lot of sound. I would further hazard a guess that the sub isn't a sub in the sense that you are thinking but probably more of a mid-bass driver.

I'd look to sell the speakers and either buy a smaller set or build your own. There are 1000s of great designs to build that will probably blow the sound away of the set that you have now anyway, and you won't really have to think too much as the cross overs have been mapped out for you already.

[Glenn Howard]

Speaker technology is not as cut and dry as throwing speakers in any old enclosure. There are precise calculations that go into the enclosure design that coupled with the speakers/drivers themselves add up to the total quality of sound.

Several years ago, a bass player friend of mind got the idea in his head to make his own speaker cabinet and use the speakers out of his amp. I warned him, but he did it anyway and the result was a beautiful cabinet that sounded like an elephant farting.

Instead of making new cabinets, maybe you could switch your focus to designing a new mounting system (removing the floor mount and moving it to the wall). That way you won't compromise the sound, but you'll still be able to mount them where you want them.

[Jim O'Dell]

snip
Currently I have a decent set of main speakers, they are floor standing and have two 5.5" drivers, a 1 " tweeter in between them, and an 8" sub at the bottom. But I don't like the enclosures, and don't like the fact that they are floor standing.
I was thinking of getting rid of these speaker enclosures, and building my own smaller ones with 1/2" MDF, veneered with real wood and finished nice. I would use the electronic components (speakers, cross-overs) from the existing speakers (cause there's nothin wrong with them) except GET RID of the 8" subwoofer and it's required cross over.
snip
Can I do this or am I messing with something that shouldn't be messed with?

The 8" driver is not a subwoofer if it is part of the current speaker box, and wires into the same crossover that the mids and tweets wire into...it is a woofer. If you take it out of the speaker, there will be some frequencies that you will be missing and a larger subwoofer in your system can't make up for them. True subs are crossed over at 80hz and lower. I'm guessing the woofer in your speakers goes up to 250hz, give or take.
My suggestion is, if you are happy with the sound of the speakers as they are, design your cabinet to look good with the size speakers you have. Recover in the veneer of your choice to make them look good. Or build boxes that the speakers will "slip" into that have their own grills. (This would actually make the speakers bigger, so probably not what you are looking for.) Only other choice would be to get new speakers the size you desire, that sound good. There are kits out there that will save you the engineering aspect that is sooo critical to a good sounding speaker. Jim.

[JayStPeter]

Definitely go somewhere else to research this. The advice here is all over the board and mostly incorrect.
My answer is that a lot of the answer is going to depend on the design of the speakers you currently have themselves. If they are designed such that the 8" and the 5.5" are in two separate volumes, you could split them up into 2 enclosures. Just ensure interior volumes match. But, if you plan on getting rid of the 8" entirely, you are probably better off getting new speakers unless you can find the specs for the 5.5 driver (50/50). You can probably drive the 5.5" lower and use a separate sub, but it would require a different crossover and probably a different enclosure volume. Check out some of the links above and visit the forums. You'll get better answers there. IMO, 1/2" MDF is for drivers smaller than 5.5". Better off with 3/4 at that size, at the very least for the baffle. It's possible that using better materials than the original enclosures with make the sound tighter. It's also possible that the crossover was tweaked with the enclosure and baffle design in place. It all depends on the original speaker design. It would require some disassembly and discussion on more knowledgeable boards to determine how well it would work.

[Frank Hagan]

As others have said, you're probably better off starting from scratch rather than trying to put your old speakers into a new enclosure. The link to PartsExpress is a good one; they have several projects listed you can look at to see how they configure the enclosure volume. They have a project right now for in-wall speakers that might appeal to you (see this link ... using these and then ceiling speakers for your surrounds might work. You will still need a bonified subwoofer (a respectable cheap one is the BIC H100 or Velodyne VX-10, either can be had for under $200 if you shop around a bit).

Right now, I'm building two of the ZaphAudio "Bargin Aluminum MTM" ("MTM" stands for "Midrange - Tweeter - Midrange") and the designer stresses that you can make the enclosures a little larger, but certainly not smaller (see http://www.zaphaudio.com/BAMTM.html). He goes into some detail on his site on how the enclosure affects the sound; its worth reading.

Because I have a separate subwoofer with a cross-over in my receiver at 80hz, I'm going with the sealed model, and the specs are that it must be at least 1 cubic foot (in the sealed version, the lower tones are not there). If I want more bass out of the speakers, I can go with the ported box, but it doubles the square footage required, and I'm already bumping up against the "WAF" with the 1 cubic foot models.