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Re: Audiophile, Budgetphile, and Dontgiveaphile thread.

Posted: Fri Jan 05, 2018 12:53 pm
by samsonlonghair
Update: The Man cave is nice and clean now; I can breathe again! I threw away about four bags of garbage from cleaning out my man cave. It feels good to purge all that junk. I also have a couple cardboard boxes full of stuff I want to sell. Maybe I'll post a few things here on the forum and see if I find anyone interested in receivers and other A/V gear.

I've made pretty good progress setting up my stereo the way I want it. I'm going for the full-fledge DTS 7.1 setup with HDMI and Blu-Ray everything on one end of the room plus a late 1970s / early 1980s hi-fi chrome-plated stereo with the record player, the cassette decks, the faux wood grain and the big shiny knobs on the other end of the room.

I'm looking for feedback on one thing. I think I have this figured out. I just want to get some confirmation from the forum because I trust y'all's opinions. Here's where I am...

I'm using a fancy-schmancy SONY reciever with DTS, Dolby, and every other digital codec under the sun. It powers my left, right, center, surrounds, and rear-surrounds just fine. My only gripe is that the subwoofer "low frequency effects" channel is not powered; it's just a line out. The manual prescribes a powered subwoofer for this. I don't own a powered subwoofer, but I do own a couple of passive subwoofers and another amplifier. I'm using a SONY stereo amplifier to power the "lfe" subwoofer like this...

SONY 7.1 --> low frequency effects output --> mono input --> SONY stereo--> subwoofer

I tested this setup with a regular old speaker that I had laying around. So far so good. Then I grab one of my big ol' bass subwoofers, and I notice a detail that gives me pause: The subwoofer is rated at only four Ohms (nominal) unlike all my other speakers which are rated at eight Ohms (nominal). I grab my other big ol' bass subwoofer. This one is also rated at four Ohms (nominal). Now the gears in my head start turning... I don't want to overheat my old stereo amplifier... What if I connect both subwoofers inline to create an eight ohm circuit? Imagine it like this...

SONY stereo output (8 Ohms) positive + terminal --> positive + terminal 1st subwoofer (4 Ohms) negative - terminal --> positive + terminal 2nd subwoofer (4 Ohms) negative - terminal --> back to the negative - terminal on the SONY stereo

What do you guys think? I've never blown an amplifier yet, and I don't plan to start. So, I'm trying to think this through and be careful. Does my logic make sense to y'all?

Re: Audiophile, Budgetphile, and Dontgiveaphile thread.

Posted: Fri Jan 05, 2018 3:42 pm
by isiolia
It's pretty normal for the LFE channel to be a line out instead of having an amp.

If you wire those 4 Ohm speakers in series like you described, you'll double the impedance (can check here or anywhere really if you search for wiring speakers in series). So that should be fine.

That said, if it's an older amp it may support 4 Ohm anyway. Seems to be a rarer and rarer thing for low/midrange gear today, but I seem to recall it being more common? Dunno. Common concern on speaker building forums, since many designs are 4 Ohm, which isn't often supported until higher tiers of home theater receivers. I built ones that were more in line with what my receiver supports, but others tend to claim few issues as long as they aren't cranking things up super high.

Re: Audiophile, Budgetphile, and Dontgiveaphile thread.

Posted: Fri Jan 05, 2018 6:36 pm
by jp1
No worries with the impedance rating while wired in series other than the fact it will cut your power output. If you aren't getting what you want out of it, then I'd consider possibly grabbing a plate amp from Dayton and working that into the box you already have. That is, if you know the specifications of the driver.

Re: Audiophile, Budgetphile, and Dontgiveaphile thread.

Posted: Fri Jan 05, 2018 9:30 pm
by samsonlonghair
Awesome sauce! I was pretty[ sure that wiring up those subwoofers inline was going to work, but it feels good to get some confirmation.

Thank you isiola and jp1. You have reassured me. You two are both awesome! Keep on Rockin'. 8)

Re: Audiophile, Budgetphile, and Dontgiveaphile thread.

Posted: Wed Jan 10, 2018 12:39 pm
by fastbilly1
The pipe that busted in the garage got most of my 80s vintage home stereo gear.

I am a bit bummed out, but it happens.

Re: Audiophile, Budgetphile, and Dontgiveaphile thread.

Posted: Wed Jan 10, 2018 1:58 pm
by samsonlonghair
fastbilly1 wrote:The pipe that busted in the garage got most of my 80s vintage home stereo gear.

I am a bit bummed out, but it happens.

That stinks, fast! :(

Was it plugged in? If it was unplugged, then it may still be salvageable. Just make sure it's absolutely, one hundred percent dried out before you plug it back in. You can take apart any separable components to expedite dry time. That would also be a good time to clean all the connectors on your components.

On the other hand, if it was plugged it, then you certainly short circuited your stereo gear.

Maybe it's an opportunity in disguise, though. I seem to recall that you're a smart, handy guy. I bet you could take one of those shiny, chrome enclosures, gut the fried electronics, and build a really cool project into that enclosure. Maybe a PC inside an 80s stereo? Could be radical!

Re: Audiophile, Budgetphile, and Dontgiveaphile thread.

Posted: Wed Jan 10, 2018 2:32 pm
by fastbilly1
samsonlonghair wrote:If it was unplugged, then it may still be salvageable. Just make sure it's absolutely, one hundred percent dried out before you plug it back in.

The pipe broke right behind were it was stored, beside my workbench to be cleaned or repaired next. The lower stuff had standing water in the case. I have the three parts that might be saved - 80s black and orange: receiver, equalizer, and fm tuner. Drying out and I will be testing them this weekend.

samsonlonghair wrote:Maybe it's an opportunity in disguise, though. I seem to recall that you're a smart, handy guy. I bet you could take one of those shiny, chrome enclosures, gut the fried electronics, and build a really cool project into that enclosure. Maybe a PC inside an 80s stereo? Could be radical!

Luckily most of the stuff lost was 90s black on black and had very little money involved. They sadly wouldnt make cool cases. I did lose a teac turntable though, it was completely underwater.

Re: Audiophile, Budgetphile, and Dontgiveaphile thread.

Posted: Wed Jan 10, 2018 4:07 pm
by samsonlonghair
fastbilly1 wrote:Luckily most of the stuff lost was 90s black on black and had very little money involved. They sadly wouldnt make cool cases. I did lose a teac turntable though, it was completely underwater.

Sorry to hear you lost a teac turntable; that's a darn shame. Sounds like the rest wasn't terribly bad.

fastbilly1 wrote:I have the three parts that might be saved - 80s black and orange: receiver, equalizer, and fm tuner. Drying out and I will be testing them this weekend.

Good luck with that, fast!

Re: Audiophile, Budgetphile, and Dontgiveaphile thread.

Posted: Wed Jan 10, 2018 5:05 pm
by fastbilly1
Yeah I was more upset that I lost the turntable than the fact that I had to flip the garage upside down.

Re: Audiophile, Budgetphile, and Dontgiveaphile thread.

Posted: Fri Jan 12, 2018 12:32 pm
by samsonlonghair
Teac is quality too. Darn shame.

But heck, tax return season is not far off now. I say get yourself a nice turntable after you get your taxes back. You deserve it. Treat yourself! 8)

Quick followup to my subwoofer situation:

I spent months and moths looking for a powered subwoofer in the thrift stores. No dice. I wired up those two passive 4 ohm subwoofers as I described in my previous post. Guess what happened the very next day? :roll:

Yes indeed, I found not one but two powered subwoofers. Now I have a subwoofer for each corner of the room. I'm not sure exactly how I want to wire this all up (or even if I want to wire it all up) but I am sure of one thing. My neighbors are gonna hate me. :wink: