# First project help - 2.0 PC speakers



## douggiestyle (Apr 29, 2008)

I'm gearing up for my first HT build, which is something I've been wanting to get into for a while now. I'm hoping to get some advice and feedback, especially on the enclosure, but please keep in mind that this is a novice project and I have specific goals in mind.

*Source: PC output/iPod into Sonic Impact T-Amp*
Sonic Impact 5065 Gen 2 T-Amp with Power Supply

I've had this laying around for a while now, and am determined to put it to use.

2 x 9 watts (4 ohms @ 0.04% THD + N)
2 x 15 watts (4 ohms @ 10% THD + N)
2 x 10 watts (8 ohms @ 10% THD+N) 
Efficiency: Up to 88% 
Signal to noise ratio: 102 dB 

*Speakers*
Morel Maximo 6x9

Amazon.com: Morel Maximo 69C 6x9-Inch Coaxial Speakers: Electronics

I picked these up because they were stupid cheap, and because I felt the higher sensitivity and increased surface area would be a good pairing for the amp's modest output.

*Design*

Cheap PC speakers for use in a 15x15 room
2.0 - NO SUB
I believe beaming properties mean that I should orient these vertically (9" tall, 6" wide)
Since the amp is portable and capable of running off AA batteries, I want to encase the amp into a third symmetrical "box" that houses both the amp as well as an mp3 player. Ideally, I can somehow attach the two speakers to the amp box and create a portable boombox.

Right now, my main concern is getting the enclosure right. I'm not sure if modeling T/S specs would be beneficial in my case. Is it wise to go ported? I'm looking to extract efficiency out of these even if it means sacrificing some SQ or super low bass.


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## XtremeRevolution (Dec 3, 2010)

douggiestyle said:


> I'm gearing up for my first HT build, which is something I've been wanting to get into for a while now. I'm hoping to get some advice and feedback, especially on the enclosure, but please keep in mind that this is a novice project and I have specific goals in mind.
> 
> *Source: PC output/iPod into Sonic Impact T-Amp*
> Sonic Impact 5065 Gen 2 T-Amp with Power Supply
> ...


We can get this all worked out for you. Can you get me the T/S specs listed here? I can model a few boxes that would sound good. 

Once that's all done, we need to determine cabinet dimensions. There's a thing called baffle loss that will come to haunt you if you don't take care of it. Fortunately, it will be relatively easy to overcome. We use a program called The Edge. 

The concept is that when you put a speaker on a baffle, the baffle width will "bounce back" or diffract certain frequencies. The frequencies it will effectively reflect back at you will be limited to the width of the baffle relative to the width of the wavelength of the frequency being bounced back. 

Using The Edge (Home of the Edge), we can simulate your specific speaker and baffle, and the program can get you a quick textbook circuit that you can build fairly easily with a soldering iron to take care of this. 

To put it very vaguely, baffle loss will cause frequencies below ~600hz to reduce in output, and will cause the speaker to sound thin. This circuit will bring back those frequencies and make the speaker sound deep, rich, and full. 

Once you get me those T/S specs, I can model an ideal volume and we can work on a specific speaker size based on that volume.


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## douggiestyle (Apr 29, 2008)

Thanks Xtreme - I've seen some of your work on here and was hoping you'd chime in.

I've read about BSC but honestly haven't taken the time to really digest the info. Best thing to do is to learn while doing 

I'll email Morel for the T/S specs as I don't see them listed online


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## XtremeRevolution (Dec 3, 2010)

douggiestyle said:


> Thanks Xtreme - I've seen some of your work on here and was hoping you'd chime in.
> 
> I've read about BSC but honestly haven't taken the time to really digest the info. Best thing to do is to learn while doing
> 
> I'll email Morel for the T/S specs as I don't see them listed online


Fortunately, there is little guesswork involved when running a full-range speaker like this one. You input the baffle and speaker dimensions into the software, and it outputs an ideal BSC network that you just buy the parts for and solder up. I can help you with that part. Past that, it will depend mostly on how good you are with building speaker cabinets.


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## WLDock (Sep 27, 2005)

With these being their entry coaxials you may not be able to get the T/S spes as they are not even listed in the manual. Not sure how serious you could get with these unless they were to be measured. If all else fails...you could always drop them in a ~ .5 - .75 enclosure with an adjustable port. Play with them just to see how they sound.

And if that does not sound like a the direction you want to go then....send those puppies back and take advantage of some other speaker close-outs. There are several cheap yet quality drivers around that would be GREAT for low cost first speaker projects.

Aurasound NS6-255-4A 6" Paper Cone Woofer 4 ohm - $11.50 each
Aurasound NS6-255-4A 6" Paper Cone Woofer 4 ohm: Madisound Speaker Store

Vifa BC25SC55-04 1" Square Frame Tweeter - $10 each
Vifa BC25SC55-04 1" Square Frame Tweeter

You could model up a simple crossover for them and find good components on sale at madisound, partsexpress, etc....


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## XtremeRevolution (Dec 3, 2010)

WLDock said:


> With these being their entry coaxials you may not be able to get the T/S spes as they are not even listed in the manual. Not sure how serious you could get with these unless they were to be measured. If all else fails...you could always drop them in a ~ .5 - .75 enclosure with an adjustable port. Play with them just to see how they sound.
> 
> And if that does not sound like a the direction you want to go then....send those puppies back and take advantage of some other speaker close-outs. There are several cheap yet quality drivers around that would be GREAT for low cost first speaker projects.
> 
> ...


Someone over on techtalk.parts-express.com already completed a design using that tweeter and driver, and Don Radick completed a design with that driver and the following tweeter a few months back. He named them the Aurbacs. I built that set and it sounds quite amazing, but at $125 in parts (not including cabinet material and small things like screws and wiring), its not the cheapest speaker to build. It sure does sound awesome though. 

Vifa BC25SC06-04 1" Textile Dome Tweeter


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## WLDock (Sep 27, 2005)

:laugh:


XtremeRevolution said:


> ...at $125 in parts (not including cabinet material and small things like screws and wiring), its not the cheapest speaker to build. It sure does sound awesome though. [/url]


Damn! The speakers are $43 How complex of a crossover did they design? I guess I will check those out.


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## XtremeRevolution (Dec 3, 2010)

WLDock said:


> :laughamn! The speakers are $43 How complex of a crossover did they design? I guess i will check those out.


Well, it doesn't have to be complex, but think about it. When the ports are on sale, they're $8 each. Terminal cups are $5.50 each, so you're already at $70. Add $6 for a sheet of acoustic foam. 

Then figure a 3rd order on the tweeter, L pad, and a 2nd order on the woofer, and what are you at? Those two inductors alone will run you $25 and from there you're not too far off. 

It all adds up pretty fast when you're looking at the overall cost of building a speaker. If you make it out of hardwood, you pay for the hardwood. If you're making it out of MDF, you have to prime it, paint it, clear coat it, and all of those paints aren't cheap whether you rattle can it or have a paint gun.

Here's the link for the Aurbacs:

http://techtalk.parts-express.com/showthread.php?t=224391


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## WLDock (Sep 27, 2005)

I guess one has to define goals and the budget. Right now he has budget car audio 6x9's.....It would not be crazy to grab a couple of the AURA MR crossovers if one wanted to try a really low cost build using the drivers above.

Aura 3 KHz 2 way Passive Crossover New FREE Shipping | eBay

$32 bucks for a driver/crossover total of $75.


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## XtremeRevolution (Dec 3, 2010)

WLDock said:


> I guess one has to define goals and the budget. Right now he has budget car audio 6x9's.....It would not be crazy to grab a couple of the AURA MR crossovers if one wanted to try a really low cost build using the drivers above.
> 
> Aura 3 KHz 2 way Passive Crossover New FREE Shipping | eBay
> 
> $32 bucks for a driver/crossover total of $75.


IMO he'd get better sound out of a coaxial than he would out of a prefabbed crossover. I'm not a very big fan of those at all. 

If you really want to do it cheap, build my TM mini bookshelf speaker design. 


























"L-pad shunt resistors can vary from 2-5 ohms, depending on how relaxed (2 ohm) or bright (5 ohms) you like your tweeter."

$3.75 ea for the tweeter
$4.50 ea for the driver
~$20 for the crossover parts for the pair if using an electrolytic cap on the midbass
$1 ea for the ports
$6 for the acoustic foam

That is if you want to go real cheap.


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## douggiestyle (Apr 29, 2008)

Xtreme - those ^ look really nice.

Like I mentioned this is my first foray into DIY home audio, and I'll be learning soldering (if needed) and getting help with the enclosure since I don't have access to equipment.

I'm also set on the Sonic Impact t-amp since I'll be modding that next, so power is limited to ~10wrms. This is why I was contemplating a ported enclosure to maximize the lower end, but I'm not expecting much below 60hz. (WLD - thanks for the vario-port idea, I think I will be playing around with that one).

I think the coax will be fine - I'm basing my expectations off of how loud a stock system can sound even off a mere 5-10wrms and cheap paper speakers. 

I'll be happy as long as these sound better than the cheap PC speakers I have now, and I have no doubt that they will. If I want to upgrade, these will probably get thrown into the rear deck of my car when I sell it.

E-mailed Morel but not expecting a response. Is the general consensus .5 - .75 liter? I'd like to port it, but maybe sealed would be the easier way to go


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## douggiestyle (Apr 29, 2008)

so the consensus is .5 - .75 cf ported then? what should I do for BSC?


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## WLDock (Sep 27, 2005)

Without specs or a way to measure the drivers....it is just taking a stab in the dark. .5-.75 should give the drivers some room to breath. If you want to play around with an adjustable port that might be fun way to learn.

Lets say you used some old plywood laying around and you built .75 cu ft enclosures. Then get some 1-1/2" - 2" adjustable ports. You could figure out what sounds best to your ears by listening to music and test tones. Just adjust the ports to different lengths, and also add equal amount of wood blocks to the enclosures to reduce the volume as needed. Just play around until things sound right. Then glue the wood blocks in if you need to reduce the enclusre volume and glue the port to the length that you like the best.

So without science(thiele-small parameters)....this will be a fun project using your ears to "tune" your enclosure to delivers the best sound.

So, just view that as a "Fun" not too technical 1st project. Once you get them built....kick back at the PC with some music playing and hop on Amazon and order up
Vance Dickasons "The loudspeaker design cookbook." This was a 1st book for many out there. Then just start reading....once you get through that start reading other books and speaker building sites. Then start thinking about your next project.


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## douggiestyle (Apr 29, 2008)

Thanks for the tip! I'll post up pictures once done


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