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Thread: My DIY stats

  1. #21
    Join Date: Sep 2016

    Location: The Netherlands

    Posts: 43
    I'm Johan.

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    Quote Originally Posted by User211 View Post
    If you have panel resonances you cannot avoid you can just notch them out digitally with a high Q value and a deep (say 10DB) cut. Provided you know at which frequency(s) they occur at. The idea is to apply a very narrow deep attenuation at the target frequencies.

    Truth be told there are plenty of speakers that resonate badly at certain frequencies panels or not, that could almost certainly benefit from this.

    Do you have any construction pics? Where did the plans come from?
    Hi thanks for your suggestions. How would you prefer to notch out the high Q resonance(s)? I've been thinking about getting a DSP but it is adding another digital device, sometimes with proprietary software, so I think something DIY op-amp based sounds better to me. (although a DSP gives more flexibility and options) I think correcting the source signal rather than the loudspeaker is a preferable idea as damping screens always affect high frequencies.

    There's some good news too: yesterday I finished my second new loudspeaker and I didn't expect an improvement in sound quality but to me it seems these smeared mid / high frequencies and the un-tight lower frequencies have disappeared. The dull, disappointing sound isn't there anymore. I was a bit disappointed as it took many hours of labor, although it was like meditation to me, those repetitive tasks. It got me away from my computer screen which is a good thing Maybe just 1 loudspeaker was exiting room modi, or the small and big stat were out of phase?

    The plans are made by myself although I read many books and articles about esl theory and construction. The idea is to divide the stator in multiple segments to tune frequency response and imporove high frequency dispersion and maybe amplifier load gets a little easier too. The dimensions were determined by outer dimensions of a door. The stators contain over 1 km of wire.

    Here are some photos I took during construction:












  2. #22
    Join Date: Jan 2013

    Location: Bristol

    Posts: 3,402
    I'm Justin.

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    Assuming you use a laptop and a DAC and have a USB test mic...

    You could try https://sourceforge.net/projects/pea...apo-extension/

    So install Equaliser APO then the Peace GUI. This is basically a configurable graphic equaliser that will allow you to insert a tight notch anywhere. You can also use it just for fun and games. I do.

    So each vertical slider is frequency configurable. Set one to your target frequency, then use a high Q value to make a narrow notch, and use the slider to take, say 10 DB off it.

    What's good is that this works for all laptop audio software e.g Spotify, TIDAL etc, JRiver.

    It's only good if you know your target frequency(s). Do that by doing slow frequency sweeps in suspect areas.

    For instance, if you hear a resonance when playing music, you could analyse it using this:

    http://www.nch.com.au/wavepad/fft.html

    If you do that I find you can quite easily "see" the instruments playing just by looking at the pattern in the temporal FFT. So if you know when and where the resonance occurred you can deduce the frequency area.

    The use the same s/w to do a sweeping sine wave based tone rising in frequency from the bottom of the suspect frequency range to the top, SLOWLY, so you hear it when the tone breaks up. So if you suspect 385Hz, do it from 360 to 410Hz, say. Note at what range within the sweep causes an audible problem, then design a notch to get rid of it.

    Of course you could stone sweep from 20 to 20KHz, but it has to be loud to hear resonances, you have to sweep really slowly, it's annoying and soon enough you will want to kill yourself.

  3. #23
    Join Date: Jan 2013

    Location: Bristol

    Posts: 3,402
    I'm Justin.

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    BTW I use a notch with the above s/w at 385Hz very, very occasionally. Why? The Apogee mid range/treble ribbon has a problem in the sense that it is split into two sections. In the longer section, the frequency that corresponds to its length means that high energy levels cause it to oscillate wildly (thanks, Morrissey!). You can physically see the ribbon go nuts, and hear it.

    I noticed this issue listening to an Ocarina being played back. I've also heard it with some brass stuff. It is very rare that it actually causes a problem. TBH the crossover could quite easily fix this by being steeper than it is as the x-over frequency is around 500Hz.

    I wonder if Apogee actually were ever aware of it for that reason. It is pretty simple maths. I'm sure they must of been. But it is so narrow band I guess they just decided to stick with mild slopes on the mid/treble ribbon.

  4. #24
    Join Date: Jan 2013

    Location: Bristol

    Posts: 3,402
    I'm Justin.

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    BTW I never noticed the resonance until I was sent an Ocarina track by the Apogee restorer, who in turn got it from the ribbon manufacturer. Determined to find out what was going on, I devised the above method.

    It is good fun when you get into it!

  5. #25
    Join Date: Jan 2013

    Location: Bristol

    Posts: 3,402
    I'm Justin.

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    Another thing you need to be sure of is that any resonances you think you hear aren't present in the source. Pretty good way to check that out is to use a decent pair of headphones as a double check. You've built a massive pair of headphones anyway in a way

  6. #26
    Join Date: Apr 2012

    Location: Southall, West London

    Posts: 30,152
    I'm Geoff.

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    Quote Originally Posted by User211 View Post
    Another thing you need to be sure of is that any resonances you think you hear aren't present in the source. Pretty good way to check that out is to use a decent pair of headphones as a double check. You've built a massive pair of headphones anyway in a way
    Yes. That's good tip.
    Mr. Tact!

    "when common sense, logic and plausibility are ruled out. All that remain are lies and foolishness"


    Gear: MMs/ADCs/Low output MC's/One rare Japanese SUT/one scarce British phono stage/various tonearms/two hefty Japanese DD TT's/hefty Japanese BD TT/smaller Japanese BD TT and small British BD TT. One CD transport/3 CD players/2 jitter buster/2 DACs/Valve buffer. One MD deck. One tuner. Two TVC pre-amps/two valve pre-amps/solid state pre-amp/passive pre-amp. Current dumping power-amp or either of two Class A SS power-amp or Class A EL34 valve monos or big Japanese (part Class A) integrated. Big dual concentric speakers/Smaller dual concentric speakers/two way British compacts and full range speakers, amongst others. And too much more to list!

  7. #27
    Join Date: Sep 2016

    Location: The Netherlands

    Posts: 43
    I'm Johan.

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    Thanks for all your good advice! I will try the FFT analyzer and equalizer.

  8. #28
    Join Date: Sep 2016

    Location: The Netherlands

    Posts: 43
    I'm Johan.

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    Just af few days ago I received the last 32 resistors for the second stat for electrical segmentation of the stators. Last two nights I compared my DIY panels to a set of Final 0.3 hybrid stats that were stored in my house, they belong to a family member. I'm happy to conclude that my DIY stats sound better than the Finals: clearer, more detailed, tighter bass. The Finals sound a little dull and hollow compared to the big stats. But the Finals are still quite good in my opinion given their much smaller size. I'm not sure if they are very good reference speakers, I've read some posts about problems with wrong filters, dips in frequency etc., cheap woofer together with some very positive reviews. But for now I'm happy with my new stats. Still not sure how they compare to other DIY stats and commercial stats like Martin Logan, Acoustat, Quad, Sanders Sound etc. and to magnetic loudspeaker systems.

    I'm considering to build a (magnetic) woofer to supplement for low frequencies (below 100 Hz). I think it will be a sealed or transmission line woofer. Still not sure, but to me it sounds interesting. I'm wondering if those lower frequencies will add valuable musical information to the overall sound?

    Picture below: comparing the Final 0.3 hybrid stats to the new DIY panels (white stat in middle was not connected)



    By the way, I tried to install Windows Vista on an old pc to run the EQ software, but it failed as it was too slow. I will retry soon with my fast pc.

    Regards

  9. #29
    Join Date: Jan 2008

    Location: Forest of Dean, Glos & Cambrian mountains, Wales

    Posts: 9,196
    I'm Jerry.

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    Awesome! They look fantastic.
    Jerry

    Spotify Premium streaming, Cambridge Audio 851D DAC/pre, Nobsound NS-02G amp, MBL116F
    or
    Spotify Premium streaming, Wadia 151 PowerDAC, MBL 116F.
    or
    Spotify Premium streaming, Cambridge Audio 851D DAC/pre, Pass Labs X150 power amp, MBL 116F.
    or
    >> Currently >>Spotify Premium streaming, Cambridge Audio 851D DAC/pre, LA Audio A-30 el84 integrated amp, MBL 116F.

  10. #30
    Join Date: Jan 2013

    Location: Bristol

    Posts: 3,402
    I'm Justin.

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    They do look great - didn't realise just how much bigger they were than the previous pair.

    Be curious to see an FR plot with the mic at the listening position.

    Dipole subs would be a good idea I think. Since the main speaker is a dipole, I'd be really tempted to maintain that aspect all the way down.

    How about an OB woofer with some huge drivers? 15 inchers... get yerself some proper radiating area...

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