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Dayton 460PA-8 Efficiency

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  • Dayton 460PA-8 Efficiency

    Anyone ever have any problems with a Dayton PA460-8? I built two 7.6cuft slot ported bass reflex cabinets tuned to 34hz. Powered by 1 Bryston 4B (in mono 800w) per side and these things barely put out any bass. Checked all my wiring, phase, balance, etc. tried running one at a time. Im getting like half the bass from both running than my Klipsch RF5 speakers and pushing my amps to the limit. Any ideas? Bad batch? Is my cabinet out to lunch?
    YO

  • #2
    YO

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    • #3
      Did you confirm that the boxes are tuned correctly? An impedance sweep should be enough to do the job.

      What made you decide on that particular box size and tuning btw?

      I haven't used the 460, but it's little brother the 310 performed exactly as I expected
      Brian Steele
      www.diysubwoofers.org

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      • #4
        Brian Steele box volume was chosen from reading about the vbss project(s). Also posted some volumes and tuning frequencies in another post and it was generally well received. Port dimensions derived from others advice and checked on a few calculators online. How do I run an impedance sweep?
        YO

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        • #5
          (where) are you low-passing these?
          Your box volume looks to be 7.6cf.
          To get a tuning of 34Hz, I see a (2.5"x22") port length in the 17"-18" range.
          Off your drawing, your length looks to be more in the 10"-11" range. That's an Fb more like 40Hz, but that's where I'D tune this box.
          Looks like an F3 between the mid 40s and upper 30s (depending on the LP freq.).
          (Your Klipsch have a claimed F3 in the mid 30s - so these won't go quite that low.)
          Not really 30Hz for a movie's LFEs, but should reach down to the bottom end of the traditional "rock" range.
          In a 15cf box, tuned to 34Hz (a 3" long vers. of YOUR slot vent), their F3 should be in the low 30s, but then Xmax-limited to 175wRMS down to 30Hz.

          They should be able to take 350wRMS @ 60Hz, making 120dB @ 45Hz.
          That should make that size room rather uncomfortable, I'd think.
          How many volts are you seeing at the driver terms. w/, say, 100Hz tone.
          Run some test tones and tell us what you're missing?

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          • #6
            Chris Roemer not sure how I got the tuning frequency so wrong. When we last spoke and I was considering a 9cuft box your measurements were closely matching an online calculator I was using to verify. Ive attached a photo of the calcs I used for the smaller box. Either way, lets say the box is tuned anywhere between 35 and 45hz. The output with my 800w amplifiers cranked is still way way less than I would expect it. Additionally I find that the woofer does not match the efficiency of the mid driver I selected with a similar efficiency in any frequency range (like the woofer is two orders of magnitude quieter). I dont have any testing equipment. I basically have a preamp, amp, and a bluetooth module to connect my phone to my preamp. Is there a tone app I can use through my phone?
            YO

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            • #7
              Sorry K. In the "light of day", it looks like your box IS tuned near 34Hz after all (but, personally, I'd bump it up to 40Hz, or low 40s).
              (I DO have to shift back & forth a lot - sometimes, between cu.ft. and liters, and possibly WinISD got "confused"? It can, but I usually see something's wonky.)

              Since you don't have test tone data, can I ask what freqs. you were expecting out of it?
              I don't think you got 2 bad drivers, but w/out sufficient signal (like in the pre-amp chain, or even the source) your power amp can be running full gain without producing adequate voltage on its output.
              You can't really verify that w/out any test equip. You can get a DMM VERY cheaply at Harbor Freight.
              Are these "subs" being low-passed?

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              • #8
                I like Tone Gen Pro on my iPhone. It is easy to use and super handy.

                Like Chris said - get a DMM. It doesn't have to be fancy; Harbour Freight has one for under $25 that will do what most people need of it.

                Even without one, with 800watts those woofers should be moving quite a bit when you get on it. Are they?

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                • #9
                  Chris Roemer the bins are just the woofer section of a three way cabinet. Crossover frequencies are 375hz and 3000hz. Tried wiring directly from amp to just woofers (full range) and the bass was just as week. The RF5s with dual 8” woofers dominate over and 18” with same claimed efficiency. Also tried another integrated amp I have to see if my pre/power amps were the issue and I am getting same result. Really honestly perplexed as to what is happening here. Ready to throw them in the river. If anyone happens to live near Niagara Falls and could come test them for me I would appreciate it.

                  Ive built a single driver full range speaker in a transmission line (fostex fe206e), mtm using dayton 6-1/2” classic woofers, and a wwmtmww using 8” morel woofers, plus owning these rf5s have all have SIGNIFICANTLY more bass than what I am getting from the woofers. Connections to the woofers are the spring loaded terminals so I doubt Ive screwed that up. This all kind of sucks because they were being built for a friend, and theres no way I could give or sell these to anyone, they are almost comically bad. Walmart boom boxes have more bass
                  YO

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                  • #10
                    Dukk i will check out ton gen pro. I also have an iphone. Forgive my ignorance but what is a DMM? Does harbor freight ship to Canada?
                    YO

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                    • #11
                      DMM = Digital MultiMeter. Not sure about HF shipping to Canada. I live just 6km from the Washington border so I go to the one in Bellingham when I need something. Parts Express has a few DMMs that are good prices, and there is always Amazon or Canadian Tire..

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                      • #12
                        Dukk Chris Roemer I have a digital multimeter, not sure what to do with it in this instance but perhaps you could walk me through it. I will get a picture of it this weekend. I really appreciate all of the help!!!
                        YO

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                        • #13
                          So... you can use the same amp playing your RFs, PAUSE the input source, take the 2 amp leads off your Klipsches and put them directly onto your 18"ers! and almost nothing!

                          Now, the dual 8" RFs are most likely 4ohm nominal (I THINK i read their sensitivity is supposed to be 99dB? w/a bottom end (F3) in the mid 30s???).
                          The PAs are 8ohm, rated near 97dB. Being 8ohm, with the same voltage they'll get half the current, which will be half the watts. They wouldn't sound as loud.

                          How are you crossing these 3-ways? All active? All passive? Half & half?
                          If you can run tones through them, 100Hz should be about the loudest, F3 should be between 50 and 40Hz. 30 might not sound loud, but your drivers should be movin' !

                          Set your DMM to "AC volts" (looking for a range between 5v and 50v, probably). Play a tone you can re-create (100Hz, 200?, 400?). Put the Red/blacK probes on the R/K terms on the RF cabs and read the voltage (while playing that tone). Do the same w/the 18s. How do the voltages compare?

                          You do have these boxes sealed up, right, except for the port opening(s)?

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                          • #14
                            Originally posted by killerkowalczyk View Post
                            Powered by 1 Bryston 4B (in mono 800w) per side
                            Ah... Nope. That would be 800w into 1 channel created by bridging L and R channels and accessed by stacking bananas across the red binding posts. If you have the subs connected normally to L and R outputs they are only getting 250w max and worse yet they are out of polarity and cancelling each others output.

                            And what are you driving this with? Is it capable of making the clipping lights on the amp activate?
                            Paul O

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                            • #15
                              Chris Roemer . I will check my cabinets and drivers etc to ensure they are sealed properly. The RF5s are 8ohm nominal, albeit slightly higher efficiency. My last speakers were WWMTMWW with a suspected efficiency of about 91db and they were more efficient/louder than this single 18” by far. So something is going on.
                              YO

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