Long Run Powered Wires

Discussion in 'Home Theater Projects' started by SammyXP, Jul 31, 2006.

  1. SammyXP

    SammyXP Auditioning

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    I'm designing an attic-mounted big subwoofer (Dayton Titanic in ~Adire Alignment). I'm hesitant to put an amp in the blistering heat of a South Mississippi attic, so I've thought about an in-room, rack-mount solution like the Behringer EuroPower series.
    Has anyone run long lengths of 1500 watt-powered wires? By long, I'm talking approximately 15-20 feet, max.
     
  2. Robert_J

    Robert_J Lead Actor

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    Not a problem. Just use some quality 12ga speaker wire. I ran the subs off my EP2500 with 25ft of wire until I got my sub cable run through the attic. I had no problems.

    That amp is way overkill for the Dayton DVC. It would work fine with a 300w amp. Also, the EP2500 is available from PE for $299 with free shipping.

    -Robert
     
  3. Ryan Schnacke

    Ryan Schnacke Supporting Actor

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    If you're going to the trouble of building an attic-mounted sub, why not build an infinite baffle subwoofer?

    www.infinitelybaffled.com
     
  4. Brent_S

    Brent_S Second Unit

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    15-20 feet's not long at all.

    I'm more concerned with trying to feed 1500 watts into a Titanic! What are the particulars of your alignment? Even 6 ft^3 tuned to 20hz is going to leave you with pieces of a Titanic 15 laying on the floor if you hit it with 1500 watts. A bigger box is going to need even less power to reach Xmax. Excursion limited power in the 6/20 box would be a bit over 600 watts in the 25-30hz range.

    -Brent
     
  5. Robert_J

    Robert_J Lead Actor

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    I read DVC the first time. Still, it's overkill like Brent says. A TC-3000 would handle 1,500 watts without breaking a sweat.

    -Robert
     
  6. chuckg

    chuckg Supporting Actor

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    In the world of movie theaters and the like, runs exceed 100 feet all the time. I take care of two theaters with 12-gage wire running more than 100 feet to every speaker in the room.

    Just use nice big wire! I was just at the local home improvement store, and saw that 10-gage electrical wire is relatively cheap. And you don't need anything fancier than that for a sub.
     
  7. SammyXP

    SammyXP Auditioning

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    Thanks for the affirmation on the powered long cable runs.

    As for the power level - yep, it's overkill. But it's a big room and I wanted to make sure this guy had plenty of power for the 2nd sub I'm sure he will eventually want. Ryan was apparently reading my mind when I was thinking of doing a pair of IB subs as an alternative to a single enclosure. With this much power, any reduction in output should be easily overcome, so long as the power handling is there.
    I'm of the persuarion that a newcomer to HT is far more likely to blow drivers with clipped signals from inadequate power supplies than from overpowering. The EP2500 was selected mostly because it's just a killer deal as compared to a smaller plate amp or even the EP1500. (Thanks for pointing out that PE had the EP2500 for $299, Robert!)

    As for the particulars of the alignment, it's just about a striaght-up Adire alignment (214 liters with two 3" flared vents 18.5" long which corresponds to a tuning of ~15.4Hz). I love this alignment with my Dayton 15" DVC, and I've read a good number of reviews with the Titanic in the same box.

    The IB setup has got me intrigued, though. I'll see how this guy feels about an additional cutout in his ceiling and the WAF thereof.
     
  8. Robert_J

    Robert_J Lead Actor

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    Probably not in the bass region. The running the LFE "hot" will get the most reaction when showing off any system. I still demo bass heavy movies for first timers in my theater. Pro amps offer a great value but they are lacking a sub-sonic filter. You can easily overpower that sub with War of the Worlds since there are effects below the Fb of that enclosure.

    -Robert
     
  9. SammyXP

    SammyXP Auditioning

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    I suppose that there is no denying this amp is overkill, but we are now heavily leaning towards a 2x15" manifold IB setup (thanks for the site, Ryan!), so it won't be quite so overkill.
    The EP series does have a 30Hz inrasonic filter, but I suppose that's useless with a low-freq driver like the Dayton Titanic. I'm looking for a good amount of infrasonic output, though, so I'd rather go without the filter, unless one was available in the 10Hz region. Are there any affordable aftermarket infrasonic filters?
     
  10. Robert_J

    Robert_J Lead Actor

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    Drivers in an IB config are excursion limited almost always. If you run that amp in stereo, then you would be pushing up to 700w per driver. It takes about 200w to drive the Titanic to full excursion so you are wasting that amp.

    Don't even think about using a SSF on an IB. The extreme deep base is one of the best aspects of an IB.

    One of the sub choices for my HT is an IB consisting of four 15" TC Sounds subs. If I install it, I'm going to be using one of the Behringer channels to drive all 4 subs. I won't be pushing the subs anywhere close to their limits so the THD will be almost zero.

    -Robert
     
  11. SammyXP

    SammyXP Auditioning

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    Four 15" subs are pretty much what is recommended for this room, anyway (3600ft^3), but I don't know if that's quite the budget this guy was after. It's already at ~$650, plus materials, with the two 15" Titanics and an EP1500.

    Might be a good idea to do what you said and use only one channel for now. Leaves room for future expansion when he may inevitably end up with a 4-driver manifold.

    I'm also thinking in the same vein as you when it comes to ultra low THD while running this power supply at less than half its duty cycle. Extreme deep bass is exactly what I'm after with this setup. He's got 7 three-way Dayton in-walls with 8" drivers. This sub is to be a transparent extension off the deep end of the freq spectrum.
     
  12. Ryan Schnacke

    Ryan Schnacke Supporting Actor

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    You're welcome. That site is the authority on home IB subs. I've learned much there.

    Why spend $400 on a pair of Titanic's when you can get four RS15's on sale for $560? Run a pair of woofers in series to each channel of the amp. Then you're "only" pushing 560 watts. A quick simulation says you can still exceed Xmax at 21Hz or less. But it's still louder than 900 watts into a pair of Titanics and a heck of a lot more likely to survive.
     
  13. SammyXP

    SammyXP Auditioning

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    Well, he ended up going with four Dayton IB385, because of their high mechanical damping designed just for IB situations. Plus, they were only $95/ea.
    Dayton IB385-8 15" IB Subwoofer

    What are the RS15's you're referring to? The Dayton Reference series? They're $139 at PE, anyone else got them for less?
     
  14. Scott Sabin

    Scott Sabin Stunt Coordinator

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    Sammy, please post photos of the IB as you go. Also, how are you driving the 4 Dayton IB drivers? If I recall, they are 8 Ohm drivers. I am planning on either 2 or 4 of these same drivers, but with each pair being driven by a PE 250W plate amp with LF sub filter. If I used 4, I'd need a second amp, but I would only have ot match outputs of each pair once and I'd be done.

    Are you planning the same route, or going with a more expensive amp?
     
  15. SammyXP

    SammyXP Auditioning

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    The amp I recommended for this install was the Behringer EP2500. It's way, way more power than is needed, but costs about the same as a plate amp. We were also very concerned about the temperatures in a deep south attic for 9 months of the year and so wanted a rack mount amp we could mount indoors with a long run of powered wires (Yes! Back on topic!).
    You're correct that the Dayton IB's are 8ohm. We are planning on running a pair of the drivers in parallel on each channel to provide a 4ohm x 2 load to the 2 channel EP2500. Since the IB's are VERY excursion limited (mfg lists a 100w excursion limit, with a 350w thermal limit), I'm thinking about actually wiring them in series to provide a 16ohm x 2 load. Guess it'd make more sense to just run 4ohm x 2 and limit the gain on the amp to keep overanxious fingers from overdriving the drivers and hearing that dreaded voicecoil slap.

    I'll definitely post pics when the materials arrive in a week or so, and we begin the install.
     
  16. Robert_J

    Robert_J Lead Actor

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    That would be the best since these drivers have some mechanical noise when driven hard. It also allows for future upgrades without getting a new amp.

    -Robert
     
  17. Ryan Schnacke

    Ryan Schnacke Supporting Actor

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    Dayton is Parts Express's house brand. There's a few other guys selling Dayton woofers but they basically drop-ship them from directly from PE. No significant price difference.

    Yes, the Reference Series 15 inch HiFi woofer is what I was referring to. You'll find that while it has similar displacement capability as the 15 inch IB subwoofer, it is really a much higher quality design and build. $139 is a good price for these. Still, the IB15 is a good woofer and very cost efficient.

    Speaking of efficient, these woofers are quite sensitive in the low ranges. The EP2500 really is a ton of overkill in this case. I probably would try running a pair in series for each channel like you mentioned. You'd probably get around 125 to 150 watts per woofer. That sounds a lot safer than 350 watts per woofer.

    This should be a fun project.
     
  18. SammyXP

    SammyXP Auditioning

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    16ohms in series it is then. Better to be safe than sorry. I'm glad to hear that the IB15's aren't a mistake. They're cost efficient, for sure. With this much power, it makes me wonder what two sets of 4 manifolded drivers would sound like. *evil laugh*
     
  19. Scott Sabin

    Scott Sabin Stunt Coordinator

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    I see that the Dayton 250W sub plate amps are discontinued. Well, at least the one that I wanted with the high pass filter. They were pretty sweet at $120 or so, so even two of these would have been cheaper than the Behringer, albeit only by a small amount.

    I look forward to seeing the pics of the install, and more importantly, hearing about the final product!
     
  20. SammyXP

    SammyXP Auditioning

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    I'm using the Bash 300S Digital Subwoofer amplifier with a Dayton DVD in a Tempest alignment. It's about the same price as the Dayton 250w at $129, although it lacks a subsonic filter (which was a selling point for me). Great amp, runs cool all day.
     

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