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  • B-652's

    i just got a pair of Dayton Audio B-652 speakers. The specs say the impedance is 6 ohms but when i peeked at the in'ards there was two 4 ohm drivers in parallel. Isn't that a 2 ohm load? There was a 6.4 uF cap on the tweeter (+) terminal, how do i calculate what crossover frequency that might be? i have a Pioneer FH-X731BT head unit with which i will be driving the speakers and it has a network mode where i can do the crossover in the head unit and drive each driver with its own channel. You guys probably know all about it but i think it's the coolest things since slice your own rye bread!

  • #2
    The woofer has rising impedance with increasing frequency and the tweeter has a HP filter via the cap. The minimum impedance of each driver does not overlap in the frequency domain and thus does not "sum" to 2 ohms. With a standard XO, lower frequencies go to the woofer and higher frequencies go to the tweeter. And while the woofer does not have a LP filter, it appears to the amp as if it does have a LP due to the rising impedance.

    Google "B652 Mods". The TT thread on that topic will show many different upgrades but it will also give you an understanding of the drivers' useful freq. range. There may even be an impedance graphs for the stock drivers (haven't looked, it's a long thread).


    • #3
      Jay, set the B-652's aside for future "surrounds" and buy a pair of the Classix II flat-pack kits. Your ears will thank you.


      • #4
        Thanks Millstonemike, for explaining that. I suppose adding a zobel would flatten the impedance but also drop the system impedance? i will google "B652 Mods"; it was my plan to play with the speakers and improve them over time (if i can) but my primary listening is with cans due to neighbors.
        Thanks Whitneyville1 but i daren't get speakers that won't make me putz...


        • #5
          i just read the B652 mods thread and i have to say that i have no opinion on surface area vs. excursion, however my wife seems to think they are both good ideas. Some 25 years ago when i built my first and only speakers my design centered around the inside dimensions and how they related to supporting wavelengths of concurrent 1/3 octave spreads. Are the enclosure dimension ratios still important for reinforcement or do other things take precedence in current design thinking?

          i got the B652's mostly due to their small size, however i am a woodworker and calculate i can go as big as 9.5"w x 12"h x 14"d of .75 MDF for an internal volume of 0.607 cu ft. Plus an aperiodic port if i can find a proven DIY design (the Scan Speaks are $23 each now!) i'm planning on replacing the tweeter with the Tymphany BC25SC06-04 with Zobels on both drivers. i'm driving the speakers with a car head unit (Pioneer FH-X731BT) which has the ability to drive the twts with LF & RF, the woofs with LR & RR, do HP & LP crossover at various frequencies, 6,12,18,&24 slopes, and set individual levels. i use the full sig subwoof outs to drive a Sure Headphone Amp. i accidentally ordered 2 headphone amps so i used the extra one to bring up the level of my computer audio board, but there's some digital noise there.


          • #6
            Jay, I don't mean to rain on your parade, but I've done ridiculous things to the B-652's for little gain. You're putting lipstick on a pig. Zaph's mods accomplice 90% of all you can do with them. Spend the $21 of the tweeters on either the Overnight Sensations kit or even the "C-Notes" kit and I promise you, either will give you better sound quality than replacing the woofer and tweeter (and designing and building a new cross-over) on the B-652's. The woofer and tweeter in the stock B-652's just aren't capable of producing meaningfully better sound quality, no matter what you do to them, and believe me, I tried a new enclosure and lots more. With lots of mods and money can you make the B-652's sound better? Yes, but at what cost? If you just wanna mess around with them as I did, that's OK, but don't expect much for your efforts. They are a little improvement over the tiny speakers in the new thin TV's, a pre-teen or very early teen might be happy with them, with the Zaph mods, they are nearly passable surround speakers for 5.1 or 7.1/7.2 home theater. Yes they produce sound, but not really good sound.