Engineering Student

Message
Author
rcko
Posts: 23
Joined: Mon Sep 26, 2011 9:59 pm
Location: Houghton, MI

Re: Engineering Student

#16 Post by rcko »

So more like a $100 2x100-Watt RMS Sherwood RX-4109 for the two TLAH's?:
http://www.amazon.com/Sherwood-RX-4109- ... pg__header

and $110 Dayton SA-100 for the TT?
http://www.parts-express.com/pe/showdet ... er=300-802

Just split the signal from my laptop with a good quality splitter and send it to both amps? Is there a better way to get the signal to two amps?
I was thinking http://www.amazon.com/Belkin-F8V234-WHT ... 356&sr=1-2

User avatar
DJPhatman
Posts: 5412
Joined: Mon Aug 14, 2006 5:08 am
Location: Warren, MI
Contact:

Re: Engineering Student

#17 Post by DJPhatman »

No on the Sherwood, as it does not have a LF out, IOW a crossover, built in.
Will this ever be used for HT? Pick up a cheap HT 5.1 receiver, or go the pro route, and get a used mixer, crossover and stereo amp. I would go for the HT 5.1, myself. That will get plenty loud.
I know money often seals the deal, but seriously, quality is an investment, not an expense... Grant Bunter
Accept the fact that airtight and well-braced are more important than pretty on the inside. Bill Fitzmaurice

User avatar
jcmbowman
Posts: 1263
Joined: Fri Feb 01, 2008 3:40 pm
Location: Detroit, MI

Re: Engineering Student

#18 Post by jcmbowman »

For splitting the signal, you may wish to consider one of the options here:

http://www.minidsp.com/

You are an engineering student, right?

;)
Low End Junkie for over 20 years.

4 DR250s
4 Tuba36s @ 30" wide
2 ATs
...and a very serious addiction to the smell of BB sawdust and curing PL.

rcko
Posts: 23
Joined: Mon Sep 26, 2011 9:59 pm
Location: Houghton, MI

Re: Engineering Student

#19 Post by rcko »

Chemical engineering ;-)

Besides, even engineers can be ignorant.

Those miniDSP kits look awesome, lots of ability to manipulate the signals.

User avatar
jcmbowman
Posts: 1263
Joined: Fri Feb 01, 2008 3:40 pm
Location: Detroit, MI

Re: Engineering Student

#20 Post by jcmbowman »

rcko wrote:Chemical engineering ;-)

Besides, even engineers can be ignorant.

Those miniDSP kits look awesome, lots of ability to manipulate the signals.
I have three brothers who are Chem E.'s, and my dad was a chemist for 40 years. If you can manage that level of specialization, you have the learning skills to teach yourself the basics of electronics. Engineers may be ignorant of a lot of things (social graces, pop culture, in a few cases hygiene), but one thing I know about engineers--give them a reasonable challenge, and present them with the tools or information required to overcome that challenge, and they will not rest until it's done.
Low End Junkie for over 20 years.

4 DR250s
4 Tuba36s @ 30" wide
2 ATs
...and a very serious addiction to the smell of BB sawdust and curing PL.

Charles Warwick
Posts: 586
Joined: Mon Mar 09, 2009 1:25 am
Location: Ames, Iowa

Re: Engineering Student

#21 Post by Charles Warwick »

rcko wrote:Is there a better way to get the signal to two amps?
Yes, use the 'audio out' jacks on the back of the receiver and feed it into the Dayton Sub Amp using a L/R RCA patch cable (you know, the red/white ones). The Dayton has a built in crossover that can be adjusted to whatever sounds right so you're in the green no matter what sub you end up choosing.

I would also suggest maybe checking out the local pawn shops, craigslist, or garage sales for a cheap stereo receiver to save some money; as long as it works and has near 70-100 w/channel that's all you need. I've had good luck with basic used amps and it has saved me and my friends a decent amount of money over the years.

rcko
Posts: 23
Joined: Mon Sep 26, 2011 9:59 pm
Location: Houghton, MI

Re: Engineering Student

#22 Post by rcko »

My school is in an extremely population-sparse area, not much can be found on craigslist/garage sales, etc. Pretty much gonna have to get it online one way or another.

Thanks for the info Charles.

el_ingeniero
Posts: 932
Joined: Sun Jul 18, 2010 11:46 pm
Location: Minneapolis, MN

Re: Engineering Student

#23 Post by el_ingeniero »

rcko wrote:My school is in an extremely population-sparse area, not much can be found on craigslist/garage sales, etc. Pretty much gonna have to get it online one way or another.

Thanks for the info Charles.
Ebay is your friend.

el_ingeniero
Posts: 932
Joined: Sun Jul 18, 2010 11:46 pm
Location: Minneapolis, MN

Re: Engineering Student

#24 Post by el_ingeniero »

From another thread, http://www.woot.com/ has a $155 5.1 HT receiver for sale, that is just the thing. That would leave plenty for speakers.

Edit: whoops, spoke too soon: you still need that plate amplifier, but it doesn't need a built in crossover.

rcko
Posts: 23
Joined: Mon Sep 26, 2011 9:59 pm
Location: Houghton, MI

Re: Engineering Student

#25 Post by rcko »

Bought the Pioneer VSX-521-K from Woot! last night. Should get the plans for the TLAH shortly.

Great timing! :-)

Also, threw a get together last night and I think I maybe figured out why the receiver caught fire. Normally only a rope light, christmas lights, and audio receiver are plugged into a power strip. When a keg is running, a mini-fridge may be plugged in too. With the mini-fridge also plugged in last night the rope lights almost caught fire, after running fine for 5 hours with no mini-fridge running, (then I plugged in the fridge) the rope lights started melting and burning the plastic housing plug-in thing in between sections of rope. Smelled awful.

There's probably a better way to distribute the load in the future, but I wonder why, if the power strip or outlet was overloaded, why didn't it heat up instead of the rope lights?

User avatar
Tom Smit
Posts: 7457
Joined: Sat Jan 05, 2008 1:24 pm
Location: Sarnia, Ont. Canada

Re: Engineering Student

#26 Post by Tom Smit »

Maybe a voltage drop on that power bar because of the mini fridge kicking in, thus increasing the current flow through the lights which was within limits when it is just one string.
TomS

rcko
Posts: 23
Joined: Mon Sep 26, 2011 9:59 pm
Location: Houghton, MI

Re: Engineering Student

#27 Post by rcko »

http://www.parts-express.com/pe/showdet ... er=299-278 (Peerless 4.5" 4-ohm)
These are on a good sale. Will they work any better than the Goldwood GW-204/4S (which are $0.30/ea cheaper).

Also, would these fit my wants or are they crap?
http://www.parts-express.com/pe/showdet ... er=292-404

Thanks!

P.S. Bought plans for TLAH and Long-Version Table Tuba. Plan to start construction of TLAH next weekend.

Also, with regards to impedance, I think it makes sense to wire up 8 of the Peerless 4-ohm speakers to get an 8-ohm circuit. The VSX-521-K receiver can output 110W through 8-ohms. Being that each speaker is rated to 30 Watts-RMS (240W total) will the receiver output enough power for the system?

rcko
Posts: 23
Joined: Mon Sep 26, 2011 9:59 pm
Location: Houghton, MI

Re: Engineering Student

#28 Post by rcko »

Also, if I used 10 8-ohm tweeters to get an 8-ohm network, would that work as well/better than 12 tweeters at 5.3 or 10.64 ohm equivalence? (2/3, 4/3 that of individual, respectively)

rcko
Posts: 23
Joined: Mon Sep 26, 2011 9:59 pm
Location: Houghton, MI

Re: Engineering Student

#29 Post by rcko »

From the plans: "The preferred mid-bass driver size is 4 inches, but you can go a bit smaller or a bit larger if you desire, making the cabinet longer if larger drivers necessitate it. The target T/S specs are fs 100 Hz, Qts .5; somewhat lower fs and higher Qts doesn’t hurt. Vas is not important with drivers this small."

For the Peerless 4.5" driver: http://www.parts-express.com/pe/showdet ... er=299-278

Fs: 114 Hz
Qts: 0.62

Right now it's my favorite ($8/ea when I get 16 of them!) but I don't know how these numbers will affect things. Thoughts?

rcko
Posts: 23
Joined: Mon Sep 26, 2011 9:59 pm
Location: Houghton, MI

Re: Engineering Student

#30 Post by rcko »

http://goo.gl/v8WNw
So I guess that this design for tweeter wiring would be bad because the final two speakers would be running at 4x the wattage of the other 8 tweeters?
The idea was to get an 8-ohm equivalence over the circuit as a whole.

Image

Post Reply