Making a center speaker, have some questions.

[Atimm693 10+ year member]

My HT is needing a center speaker, so i need some opinions about how id go about doing this.

First is the enclosure, im not buying one, and i have tons of spare wood laying around. I just learned how to design sub enclosures, so i have no idea what to tune to or what cubic feet. Here is a quick design i drew up. I just got the dimensions as to what would fit under my TV. According to me it should be around .18 cubes before displacements tuned to 150 htz. I had no idea what to tune to, so this is just a general number. Is it even worth porting these or should i just seal them up?

Second is the drivers, i dont want to mess around with anything except full range drivers, becuase if i get anything else ill have to cross them over and whatnot. I have these two picked out. Also, being these are 8 ohm, i could do 4 ohms (which my reciever is stable to), and risk overpowering them, or 16 ohms. Would this be underpowering them. I would like to have strong midbass for guitars and drums with mellow highs. These will mostly be used for music, which consists of mostly rap, and some heavy metal (atreyu, korn, disturbed etc.) Sometimes for movies, but not as often as music.

http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=297-428

I want to spend around 40.00 shipped for them, this is a budget project.

Heres the setup:

Front: Cerwin Vega VS-8s

Rear: none

Sub: 8" Kicker Comp

Sub amp: Hifonics TXI-4006 (~300 watts is what my PSUs will supply to it)

Reciever: Yamaha HTR-5560(http://www.yamaha.com/yec/products/productdetail.html?CNTID=200182&CTID=5000400)

The Cerwins lack midbass, which is why i want it to be strong on the center. I want a nice 2.1 setup as you can see.

Click to read more...

 

[BrianChia 10+ year member]

Horizontal placement creates lobing problems between the two drivers at high frequencies. The further apart you place the drivers the lower the frequencies will be before lobing starts to become an issue. You will get off-axis interference/cancellation of certain frequencies if you aren't listening directly perpendicular to the radiating axis of the drivers. It would therefore be best to use only a single full range driver, or use 4 or 5 placed very close together to try to minimize comb-filtering, or at least place them in a vertical configuration with close driver spacing.

As far as tuning is concerned, you want to tune to driver specs to achieve a flat response curve. You don't want to just pick an arbitrary frequency. Usually the Fs of the driver gives a close approximation but the best way to predict the tuning and enclosure volume would be to model the driver in a program such as Unibox or WinISD.

 

[JimJ 5,000+ posts]

I want a nice 2.1 setup as you can see.

3.1, as you're going with a center...and two-channel music isn't going to take advantage of that unless you have processing to upmix it.

 

[Atimm693 10+ year member]

Horizontal placement creates lobing problems between the two drivers at high frequencies. The further apart you place the drivers the lower the frequencies will be before lobing starts to become an issue. You will get off-axis interference/cancellation of certain frequencies if you aren't listening directly perpendicular to the radiating axis of the drivers. It would therefore be best to use only a single full range driver, or use 4 or 5 placed very close together to try to minimize comb-filtering, or at least place them in a vertical configuration with close driver spacing.

As far as tuning is concerned, you want to tune to driver specs to achieve a flat response curve. You don't want to just pick an arbitrary frequency. Usually the Fs of the driver gives a close approximation but the best way to predict the tuning and enclosure volume would be to model the driver in a program such as Unibox or WinISD.

Would maybe 4 of the drivers i selected work better? I put in all the T/S params PE had for the drivers into WiniSD and it had them at 29 htz at 3 cubes, so i started over with my design. Airspace is the same, but its tuned to 80 htz. (Fs:77htz)

3.1, as you're going with a center...and two-channel music isn't going to take advantage of that unless you have processing to upmix it.

The reciever has options in the menu for large, small, or no center.

 

[BrianChia 10+ year member]

Yeah I'd go with 4 or 5 drivers (really, the more the better but it does get expensive), spaced as close as physically possible. Also I'd probably find a way to put the port on the front. Maybe two circular ports on the left and right of the drivers. I would try about 0.1 cf per driver tuned around 80hz.

 

[Atimm693 10+ year member]

Heres another i drew up quick, i really only want to do three because its within my budget and because i really dont want to make it any bigger. Right now its .31 ft^3 tuned at 80 htz.

 

[cshaw 10+ year member]

why not fix your front stage, since thats what you dont like. dont add more speakers to the confusion.

 

[Atimm693 10+ year member]

why not fix your front stage, since thats what you dont like. dont add more speakers to the confusion.

I like the fronts, its just they lack midbass being they have a woofer and a tweeter, thats it.

Do you think it would be better to just take these drivers and make them into bookshelves?

 

[JimJ 5,000+ posts]

its just they lack midbass being they have a woofer and a tweeter, thats it.

I don't understand.

 

[PV Audio 5,000+ posts]

I like the fronts, its just they lack midbass being they have a woofer and a tweeter, thats it.
Do you think it would be better to just take these drivers and make them into bookshelves?

This is a blatant contradiction. Something is wrong with the speakers, as that's what a woofer is there for: midbass.

 

[thylantyr 10+ year member]

"To the optimist, the glass is half full. To the pessimist, the glass is half empty. To the engineer, the glass is twice as big as it needs to be."

edit:

"To the optimist, the glass is half full. To the pessimist, the glass is half empty. To the average engineer, the glass fell on the ground and broke into pieces as he is clumsy working with his hands, to the audiophile, the glass cost $5000."

 

[Atimm693 10+ year member]

This is a blatant contradiction. Something is wrong with the speakers, as that's what a woofer is there for: midbass.

Im not sure what really is wrong, i just dont like the way they sound on the guitars, id like them to have strong midbass. I think the woofer is either crossed over low, because its loud on rap, if i turn it up loud enough, or its the way i have them EQ'ed. Mabye the boxes are tuned too low?

The cerwins were made in the mid 90s, so maybe that has something to do with it?

EDIT: Just calculated the box for the cerwins, its approx. .9 ft^3@46htz

 

[JimJ 5,000+ posts]

I would build new speakers, personally.

If you have tons of spare wood laying around, a pair of BIB's would give you all the midbass (and subbass, for that matter) you could want //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[BrianChia 10+ year member]

Get a parametric EQ, maybe?

 

[Atimm693 10+ year member]

I would build new speakers, personally.
If you have tons of spare wood laying around, a pair of BIB's would give you all the midbass (and subbass, for that matter) you could want //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

I dont have the money for new speakers at the moment, and they arent the biggest concern either, im currently saving up for the equipment in my van.

Could you clarify what BIB's are?

Im just going to build them into bookshelfs, if anyone has anything else to chime in im ordering the speakers tonight so chime in now.