1st speaker project - was: New Idea For a Small Business, at age 15! (Moved) (1 Viewer)

[bobbyg2]

I already have a design picked out, the Dayton 8's. I was thinking of puttin the tweeter on the top and having the woofers below it though.

 

[Robert_J]

Since you haven't done your speakerbuilding homework of reading the Loudspeaker Design Cookbook, I'll let you in on a little thing. Any time you change the layout of the speakers, you will have to tweak/redesign the crossover. The D8 is an MTM. Changing it to a TMM and not changing the crossover will have a negative effect on the sound quality.

-Robert

 

[bobbyg2]

Alright, thanks.

The designing of the enclosure requires an understanding in correct measurment, design, and layout. Am I correct? Because I understand the measurment and design part of it, and a basic understanding of layout. All I really need to focus on at the moment is crossover design. I'm getting the internet at my house tonight (I'm at school right now) and will read up a whole bunch of things on crossovers tonight.

And I was wondering, my uncle got me 150ft of 24 guage wire. I don't think it's big enough for my application. Do you think I should double-wire the speakers when I hook them up?

*EDIT*
And for you people who think 15" is big... Take a look at this! The biggest Subwoofer Ever Made

 

[Robert_J]

Order the Cookbook when you order your parts from PE. Read the book as you build the D8 speakers. That way you will understand what went into the design. There are things like the width of the baffle and tweaking the crossover to compensate for it (baffle step compensation). There's also the spacing between individual drivers based on the crossover frequency.

24 ga wire will be fine for internal wiring. It may even be fine to connect the speaker ot the receiver if the runs are under 10 feet or so.

That sub keeps popping back up. Richard Clarke and Dave Navone built it as a proof of concept. The "magnet" portion of the sub is actually a servo motor that moves the cone back and forth. Just like the Contrabass except on a larger scale. It's not very practical though. It's much easier and cheaper to install multiple "smaller" subs than a massive 5 foot one. There are numerous examples here. But if you want "massive", then Clarion has a 36" sub, Audiobahn has a 30" model and Hemp Acoustics has a 25". All three can be easily stomped in the dirt by the 18" LMS 5400 from TC Sounds or the 18" XXX from Resonant Engineering installed in the proper enclosure.

-Robert

 

[bobbyg2]

I was thinking of using this wire to wire up my outside speakers, neither speaker is 10ft from the receiver, least is 15ft.

 

[chuckg]

24 gage wire is extremely thin. What he meant was, 24 gage is OK for going from the speaker connection on the box to the speaker in the box - the wire only goes a few inches. I would not use wire that thin even inside the box - a little flexing and it will break loose at one end or the other.

You want 14 gage or bigger from your amp to your speaker box. 12 gage is plenty big enough for fairly long runs. Here where I work, we have 12 gage wire running over 100 feet to our theater speakers - and that's with 300 watts per speaker cabinet or more.

 

[bobbyg2]

I'll just buy myself 12-gauge wire for my home theater and use the 24 gauge for the out-door speakers. The outdoor speakers are kinda old and crappy so good-quality wire isn't necessary.

 

[Patrick Sun]

I used 16 gauge wire for internal wiring of the crossover components to the drivers inside the speakers, it's just a little more in cost, but easier to work with and is more than sufficient to not compromise audio quality and workmanship.

 

[bobbyg2]

I wired up my outdoor speakers to my receiver with that 24g. It sounds bad, but that's mainly the speakers.

 

[Robert_J]

That's ALL speaker. Speaker wire makes such a make difference in sound it will never be noticable unless you are running some Krell amps and Eggleston Ivy speakers.

Using smaller gauge wire just adds some additional resistance between the amp and speaker. Just get a quality wire between 16ga and 12ga and be done with it. Don't get hung up on name brands either.

-Robert

 

[bobbyg2]

The speakers are some old weathered Radio Shack outdoor speakers that the last owners of the house I'm in left outside. The speakers sound weathered and old. The big wire isn't going to do much improvement on already crappy speakers.

 

[bobbyg2]

I decided to design my center channel speakers. I used the shielded tweeter and woofer because this is going directly on top of my TV.

Tweeter: DAYTON DC28FS-8 1-1/8" SHIELDED SILK DOME TWEETER

Woofer: DAYTON DC160S-8 6-1/2" CLASSIC SHIELDED WOOFER

Here's a few drawings:




I know they aren't very good drawings, but at least you can see what I'm saying.

*EDIT*
This center is for after I build my towers. I will then build a subwoofer and 4 surrounds. I will build this for the living room after I'm done with my bedroom speakers. (yes, the Dayton 8's are going in my bedroom! Yes, I do realize I may end up with no walls on my bedroom! No I'm not going to get smaller speakers!)

 

[Robert_J]

If you are going with that combination of drivers for a center channel, then use the DIII design from speakerbuilder.net exactly as designed. It works great in my theater.

-Robert

 

[bobbyg2]

At first I thought you were talking about the fronts (ha! I'm stickin with the D8's) but then I realized you were talking about useing the DIII's for the center.

I heard you wrong, I was about to post "Are you talking about the speakers on the sides? 'Cuz I don't like those designs much..."

Alright, I'll do that. Also, what does the 'M' in MTM stand for? Mid-Woofer? Because I would imagine it being WTW if you were using woofers...

 

[Patrick Sun]

Typically a 6.5"-7" driver is considered a midwoofer, while larger sized driver 8" and above are considered woofers.

The center-to-center (CTC) distance between tweeter and midrange affects the maximum crossover point before you get lobing and other audio issues. The wider the spacing, the lower you must crossover the drivers to have it sound good. The closer the spacing, the higher you can crossover the drivers.

Also, for the tweeter, your crossover frequency should be at least twice the Fs of the tweeter (so if Fs is 900Hz, the minimum crossover frequency should be 1800Hz).

Your driver spacing yields 10.375", and the maximum frequency is determined by the speed of sound and the spacing = (speed of sound)/(center-to-center spacing), and in this case, the maximum crossover frequency for a CTC spacing of 10.375" is 1300Hz, which is too low if you want at least 1800Hz for the crossover frequency. Speed of sound is roughly 13,500 in/sec.

This means you need to move the midwoofers closer to the tweeter to cut down the CTC distance. If you put the midwoofers and tweeter right next to one another, the CTC distance is 5.375", and the max crossover frequency is 2511Hz. This would be enough to make sure the twice Fs requirement is met on the tweeter choice.

As you move the midwoofers further from the tweeter, the max crossover frequency goes lower and lower, and it makes the crossover work a little trickier to get to found right (meaning, you may need to use higher order filters to achieve the necessary crossover slope without a lot of bleed-through near the crossover region within an octave on either side of the crossover point).

WayneJ goes over this point on this page:

http://www.speakerbuilder.net/web_fi...m/dbp2main.htm

Anyhow, these are the types of things you have to consider when you lay out the front baffle for the drivers.

 

[bobbyg2]

Alright, will do! Thanks!

Now for the surrounds... What should I do for those? I was thinking a 2-way with a the woofer from the D8 and the tweeter from the D8.

Is that too big of a woofer to use on a surround speaker? Maybe I should stick the the smaller 6.5" woofer?

*EDIT*
I think I'm set for a subwoofer, I have the subwoofer and amp picked out:

DAYTON HPSA1000 1000W SUBWOOFER AMPLIFIER
DAYTON IB385-8 15" IB SUBWOOFER

That subwoofer is rated for a maximum of 600Watts @ 8 ohms. The amp puts out 512Watts @ 8 ohms (1kW @ 4 Ohms). So, the subwoofer shouldn't be over-driven. I'll put it in a 3 cu. ft. enclosure. I will put as much cross-bracing as I can without blocking the air flow.

I'm so excited for my new home theater system coming into the picture. You guys have been a great help and are great friends.

Thanks for all of your help so far guys!

 

[Jimi C]

Bobby, you could buy an SVS for less than what building that Dayton will cost you.

 

[Robert_J]

One of those D8 links I gave had some MT speakers with the 8" driver and silk dome tweeter. I recommend the DII from speakerbuilder.net. The 6.5" mids don't require a large box like the 8" model. I just sealed my DII's up and used a slightly smaller box. They are nice sounding speakers.

Patrick's recomendation about CTC spacing is covered in the cookbook. You will start to pick up details like that after reading it a dozen or so times.

The sub. That amp will destroy that 15" driver. KILL it. You can mostly ignore the wattage rating speakers. 95% of the time you will drive them to their maximum excursion before reaching the thermal limits of the driver. The RMS is how much power it can handle without the voice coil melting. Not how much power it takes to reach maximum mechanical limits. Plus that sub is for infinite baffle installs. To learn a little, read The Subwoofer That Shook The World.

I recomend the 15" Quattro with the 240w plate amp. There's a few designs floating around here and the PE Tech Talk Board. It's an easy build and not very expensive.

Later you can move up to an IB or something like Tom Danley just built - The Matterhorn.

-Robert

 

[bobbyg2]

Woah, I think that's just a wee bit too much bass for my neighbors... People in other cities will hear that subwoofer!

Man, 40kW? Forget bothering my neighbors, I doubt my mom will be too happy about me blowing our house down...

 

[bobbyg2]

1. The driver will be bigger (15" vs 10")
2. The bass will be lower
3. It will be louder
4. I can personalize it to my taste, not the taste of some designer

So, in the long run, I'd rather build my own subwoofer. And, since I can personalize it, it'll sound better (well, to me).

IMO, buying from a major brand isn't really worth it. I would really much rather have it sound to my taste, than to a group of scientists tastes. You will be amazed how much better home-made speakers can sound. My friends dad build himself a whole home theater system for the living room. Then he gave my friend the same amount of money to buy a HT system for his bedroom. I personally think that the $1200 worth of home-made speakers sound A LOT better than the $1200 worth of prebuilt speakers. (If anyone was wondering, the speakers were Polk [the premade ones {obviousely!}])

*EDIT*
Well, I'm getting a little ahead of myself. First things first. I need a receiver to hook up to these. I was thinking around $200 for it, but I'm flexible. Here are a few receivers I had in mind:

Onkyo TX-SR504 7.1 Channel A/V Receiver

Sony STR-DG600 7.1 Channel Home Theater Receiver with XM Connect-and-Play

Sony STR-DG800 7.1-Channel Home Theater Receiver with HDMI Passthrough


I brang this up in another thread in the Speaker forum and they suggested the Pioneer A/V Receiver (VSX-516-K). I now feel the need to choose a higher-end receiver due to the high-quality speakers I intend to build.