How many watts to power my Deftech speakers?

Discussion in 'General Audio Discussion' started by spiralmind, Aug 11, 2018 at 10:23 PM.

  1. spiralmind

    spiralmind Member

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    Hello, all.

    A while back, I had posted a question on why the bass response on my system was so low, it appeared that my Marantz PM5005 did not have sufficient power to drive the woofers in my Deftech BP10s. How much power would an integrated amp need drive the speakers at 6ohms? There have been other sites that stated that BP10s sound 'tinny and thin' without sufficient power. My system includes a small subwoofer, but the question stems more from curiosity. Thanks
     

     

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  2. musichal

    musichal poet emeritus Subscriber

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    What power does Deftech recommend for them? Go for the high end of the range.
     
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  3. spiralmind

    spiralmind Member

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    I honestly don't know. They have a sensitivity rating of 89db.
     
  4. mhardy6647

    mhardy6647 AK Subscriber Subscriber

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  5. Jayrosc

    Jayrosc Super Member

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    I had a pair of BP10's a few years back. I felt they were not very musical, but they sure put out the volume being powered by a 55 watt Sony receiver. Ya know, I never really figured out how to set them up to get the best out that bi polar thing they boast. Sold em off, but I think they were really good home theater speakers.
     
  6. Grenadeslio

    Grenadeslio Super Member

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    A Carver TFM25 should drive them nicely, or maybe a couple of TFM15cb's bridged mono, one for each speaker. I'm not surprised they didn't sound very musical powered by a 55watt Sony AVR designed for home theater use, these definitely deserve better and need more power.

    Proper setup for true bipolar speakers is crucial as with any speaker, but even more so.
     
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  7. twiiii

    twiiii Addicted Member

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    For most folks 2 watts for loud passages with twenty watt peaks with 93 db 1 meter 1 watt speakers. If you are a true audio phile add another 6 db or 8 watts with 80 watt peaks. Most folks listen around 85 db with 10 db peaks. Audiophiles and folks in the industry about 90 db with 10 db peaks. Concert level 10 or more rows back is 104 db or about 160 to 200 watts from one speaker . So maybe you could get by with 100. watts per channel for your speakers if they add perfectly and your room is in-between soft and hard. It will also depends how close you are to your speakers. Up close less than 10 ft and the sound will be more intimate further away more diffuse and enveloping. At less than 10 ft the sound will get louder beyond 10 ft less focused and yet again depending on the qualities of the room you won't loose any volume but the balance of the spectrum will change. So between moving your speakers and your listening location you can change the qualities of your system quite a bit, until you find the balance you like.

    Thats why folks love point source speakers I have come to believe, because they can change the sound. Those of us who prefer line arrays and horns like the sound of our speakers and want to retain that no matter if the rooms we place our speakers in are different. Yes, we can change the bass response balance but above 250 hz or so line arrays and above the lower crossover over frequency to the midrange horn the sound of a horn speaker stays pretty much the same. If you have a horn loaded woofer it just depends when the directionality characteristics of the horn start to fail as the frequency gets lower. With a Klipschorn the walls become part of the horn so ideally you are sitting in the throat of the bass horn for best definition.
     
  8. triode17

    triode17 Super Member

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    I have to ask. Are you sure they are phased right?
     
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  9. RickeyM

    RickeyM AK Subscriber Subscriber

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    You're not going to get a lot of bass from 6-1/2" woofers. More power will help some but there's no replacement for displacement.
     
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  10. the skipper

    the skipper Amateur Curmudgeon Subscriber

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    What Rickey said. The laws of physics is pretty strict.
     
  11. Grenadeslio

    Grenadeslio Super Member

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    Obviously you don't have experience with Definitive Technology bipolar speakers.

    Here's an excerpt from a review when the BP10 debuted.


    "The overall response variation was only ±3.5 dB from 25 to 20,000 Hz. Even at 20 Hz, the output was down a mere 5 or 6 dB from the average level at higher frequencies."
     

     

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  12. RickeyM

    RickeyM AK Subscriber Subscriber

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    I'll admit to not having experience with Def Tech speakers but as the volume gets crankin', those small woofers have a hard time going low loudly. Especially with being only driven by modest power.
     
  13. Grenadeslio

    Grenadeslio Super Member

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    Not true, these will get as loud as any sane person would ever want them to be, with the quality amplification they deserve. These retailed for $1100 in 1991 dollars, that wasn't chicken feed Back then. The BP20 was heavily on my radar back in 91 but was sidetracked by a deal I couldn't refuse on my Infintys. Still would like to get a pair, these speakers shame a lot of subwoofers.

    If you think 6.5" drivers can't produce bass at window rattling levels check out the 6" bazooka tube for car audio, I used two passive units with Rockford power in my pickup truck, impressive little suckers. Not rated as low at 39hz but it's enclosure is a lot smaller, only "one" 6" driver vs four 6.5" in a pair of BP10's , it's 100db sensitive and handles 125watts, not hard to see how deftech could actually pull this off.

    x204RS604DV-F_DMT.jpeg
     
    Last edited: Aug 14, 2018 at 9:31 AM
  14. motorstereo

    motorstereo AK Subscriber Subscriber

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    There's another Maryland based company (Polk) you may want to check out to. They've also had success over the decades with 6.5" drivers in most of their models. There's no shortage of bass even in their entry models/www.hifiengine.com/manual_library/polk-audio/monitor-7c.shtml
     
  15. Grenadeslio

    Grenadeslio Super Member

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    That model has a 10" woofer lol, but I hear you. My brother has been rocking a pair of the Monitor 5 for more than 30yrs, impressive bass from a small driver with the addition of a passive radiator.
     
  16. motorstereo

    motorstereo AK Subscriber Subscriber

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    No that 10'' is a passive radiator and not a powered woofer.
     
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  17. Grenadeslio

    Grenadeslio Super Member

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    Ah yes, fluid coupled, missed that lol.
     
  18. imral3

    imral3 Super Member

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    Here's the thing with bi-polar speakers - some days they have their highs and some days they have their lows.:naughty:
     
  19. RickeyM

    RickeyM AK Subscriber Subscriber

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    The Bazooka's got great results due to high efficiency and cabin gain. Maybe the Def Tech's would have gotten different results if they used passive radiators. Maybe the OP's results were the results of insufficient power to drive the mid-woofers to produce bass to his liking?
     
  20. RickeyM

    RickeyM AK Subscriber Subscriber

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    I see what you did there :)
     
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