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A good tweeter to match 5" SB Acoustics Magnesium Woofers

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  • dcibel
    replied
    Spec for a Bruel and Kjaer 4007 mic is 70dB SNR at 94dB SPL, though they only spec at 1kHz. Should be better than what is shown, but it wouldn't hurt to increase drive level a bit.

    Leave a comment:


  • dcibel
    replied
    [email protected] is only about [email protected], hardly torturing that tweeter at all.

    You see how the slope of the roll off flattens out below 400Hz and gets all wiggly, that's how you know you've hit the noise floor. The slope of the response here should be very predictable by the filter applied and the natural slope of the driver.

    Leave a comment:


  • xmax
    replied
    Originally posted by dcibel View Post
    What is SPL of the passband, and mic distance?

    2 arrows pointing at the noise floor, looks more like harmonics of 60Hz
    It was around 98dB, mic was about 1ft away. If it was noise it would be higher
    without the resistor. These are the small things that show up in measurements
    that I have become keen to over many years of doing this and are readily audible. I
    would have never mentioned he might want to steer clear of this design but
    I hate to see a great companies drivers used maybe not in the best possible
    way and then everybody demanded to see proof (and called me a prick lol).

    Leave a comment:


  • dcibel
    replied
    What is SPL of the passband, and mic distance?

    2 arrows pointing at the noise floor, looks more like harmonics of 60Hz

    Leave a comment:


  • xmax
    replied
    Originally posted by dcibel View Post
    Harmonic spikes based on Fs, what are we on about now? You've successfully shown that something that is louder has higher amplitude, well done. Where amplitude is nearly equal at 3kHz, distortion is equal as well. I still don't see "distortion caused by the resistor" which was your original statement. The tweeter transfer function is as it is to obtain the intended frequency response. With regards to distortion, the tweeter makes as much distortion as it makes any any frequency at the amplitude it plays, regardless of the filter in place. It sounds like you prefer to crossover higher, and would take a "less stressed" tweeter with the narrowing directivity and breakup distortion of the midwoofer over a lower frequency crossover, and that is fine if that's what you want to do.

    You are welcome to have all the opinions you want, but we are not sheep, when you make statements that appear false with an arrogant attitude, be prepared to explain yourself or you will not be taken seriously. We are a community of speaker enthusiasts, people come here to learn and share in a friendly and polite environment, so I would say it is quite rude to call someone's design wrong, bad, poor choices, etc simply because they have made design decisions that don't agree with your design opinions.

    I suggest you take any tweeter design a filter in the 1800 to 2K range listen to it, then add a 6.2 ohm resistor, correct for volume
    listen again. The reason I know this might not be the best way to do it because I have made the same mistake.
    If you take a closer look at this pic you can see the distortion is in fact higher with the resistor at some frequencies.
    Those Frequencies also happen to be harmonics of Fs. If you think this is too low in level to be audible you would be wrong.
    We are all only human and no matter how brilliant 99% of our work is that 1% gets by once in a while.

    Leave a comment:


  • xmax
    replied
    Blackstar.

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  • craigk
    replied
    Originally posted by xmax View Post
    The reason I asked: so if you mentioned a few specific artist chances are they work with one or more of my clients
    ​and it might be fun to let you know if my work had touched any of those records.
    It might be more fun to just say who you are. What Bowie albums are you associated with ?

    Leave a comment:


  • xmax
    replied
    The reason I asked: so if you mentioned a few specific artist chances are they work with one or more of my clients
    ​and it might be fun to let you know if my work had touched any of those records.

    Leave a comment:


  • DDF
    replied
    Originally posted by xmax View Post
    What are some of your favorite albums for evaluating loudspeakers? (or just enjoying yourself)
    All over the map, all types of classical (RCA, Hyperion, etc etc, many good labels) 50s/60s jazz, stoner rock, blues, some punk/heavy, 90s rap, some hip hop.....

    Any recommendations from an engineering perspective, for auditioning speakers?

    Leave a comment:


  • Psycoacoustics
    replied
    Originally posted by djg View Post
    Oh, I'm mixin', I'ma mixin' for earbuds on an Iphone, earbuds on an Iphone.
    That’s Funny!

    Now we’re having fun! Mark

    Leave a comment:


  • djg
    replied
    Oh, I'm mixin', I'ma mixin' for earbuds on an Iphone, earbuds on an Iphone.

    Leave a comment:


  • dcibel
    replied
    That's just is Kornbread, it actually disproves most of those "opinions" you've quoted. If xmax actually wanted to make the resistor look worse, he would have level matched the drivers at 10kHz so that the 3kHz bump caused by the resistor creates higher distortion at 3kHz, but in that case it would only be higher distortion because the amplitude would be higher at 3kHz, but to those hifi people that will believe anything, maybe they would be convinced ;)

    Leave a comment:


  • Kornbread
    replied
    Just guessing looking at the filter the tweeter would be struggling with the low high-pass frequency and slope made worse by the resistor "pad"
    without a shunt. I would be happy to prove it to you.

    Change the DCR of that or any tweeter 6.2 ohm higher (like what the "pad" resistor is doing) into any xover simulation.
    Or do it in actual reality and look what happens to the transfer function or actual response.
    Then look at the distortion. Then please tell me why you would want to torture any well designed driver.

    Hopefully you didn't make the same mistake for those designs, yikes...

    The truth as usual shows up in the phase response.

    All I need to see is the wrinkle at oh I don't know say 960hz... With all due respect I don't have to like every design on this forum
    and I'm guessing Frank at SB might not care for it either.


    Ok, I'm lost, what does this graph show and how does it support all of the above?

    Leave a comment:


  • philthien
    replied
    Originally posted by xmax View Post


    Yes us recording engineers are the hobo's of recorded music, you should throw your entire music collection away and listen to live music
    through a non engineer mixed live feed.
    On quite a bit of it, I wish I could at least get my money refunded.

    BTW, this is you or your brother? http://www.normandruce.com/#home

    Leave a comment:


  • xmax
    replied
    Originally posted by DDF View Post
    I think having a trained ear like a recording engineer is one of the best skills an advanced diy speaker designer can pick up, to voice crossovers with predictability. Bought this a while back, some day will have time to listen to it!

    What are some of your favorite albums for evaluating loudspeakers? (or just enjoying yourself)

    Leave a comment:

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