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Ukko Kari

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Everything posted by Ukko Kari

  1. Stuffed one port with a pillow, but I find it hard to nail down tuning exactly with the inexpensive homemade jig, though it looks close to 14 hz, which will drop some when the cabinet is standing upright, and the ports are closer to the floor.
  2. I will be building a pair, have some materials on hand for the second one now, but have to go out of the city for work so it will be some time before I complete both of them. I can certainly stuff one port and check the tuning.
  3. Added a screen shot of the impedance simulation for 16.5 cu ft net, 17.6 hz tuning.
  4. Side panels are just clamped in place at the moment, and bracing is not fully complete yet. From a quick and dirty estimate, cone excursion minima is in the 17-18 hz range. Edit: quick impedance measurement taken, tuning looks to be 17.6 hz.
  5. Ports are complete, PL max is curing, and 4 out of 6 pieces of wood are glued together, I had a good friend and AES fellow come by and help out.
  6. This is a shot of the inside of the elbow before the other lengths were added. A few coats of Duratex with sanding in between make the surface fairly smooth.
  7. Thanks! 'Respiro Del Diavolo' is the name I am kicking around for these. 😀
  8. One port out of 4 ready, second one is almost complete.
  9. Starting work on a pair of subwoofers utilizing the 8 ohm version of the DS115. Ports are sonotube, and to make them fit in the enclosure, they will have a 90 degree bend. The external dimensions of the enclosure will be 49 inches tall, 36 inches wide by 24 inches deep. Dual 9.25 inch sonotube ports will eat up about 4 cubic feet of room in the box, driver is .53 cubic feet. Bracing will be fit around the ports and the driver. External cabinet volume is 24.5 cubic feet, or 693.76 liters. Time is sparse to work on these, so they likely will not be operational until the new year.
  10. Can anyone link a video of the sound? My hypothesis is that the shorting ring or rings are loose, and moving in response to forces generated by the coil. I should check my recently purchased 21DS115 for extraneous noises before building a cabinet.
  11. Ukko Kari

    BMS 18N862

    Has anyone else noticed that US Speaker no longer lists this driver on their site? ?
  12. Interesting read, thanks. I have read a few articles from John Allen over the years, though I had not read the "Missing" article before. I concur that distortion makes a source seem louder than it actually is, and that people need to use their ears and not their eyes listening to sound.
  13. For the moment I will just replace it with another. I have a bunch of filters loaded in a DCX 2496, but work has been crazy, lots of overtime and not enough free time to swap it in with a QSC. Fast and easy to flash another Nu3000DSP. Crown should have taken notes from Berhinger on the user friendliness of the DSP.
  14. Tonight listening to music fairly loud, hitting the peak limiters in the iNuke 3000 DSP, suddenly I had red rings of death. I did have a saved preset file, and also some screen shots of the DSP settings. The amp made 6 years before it failed.
  15. I like your format. Even though the room will dominate in the actual measured response, outdoor GP is the best measure, since all devices are on an equal playing field. A 'FAQ' or frequently asked questions section on your website can answer a lot of the same repetitive questions that can tie up your time replying to inquiries. Well informed customers can then email you for additional information on your products.
  16. Just an update, I was gifted a Behringer UMC204HD at xmas. I could not get it to play nice with Windows 10, even with the latest drivers, not sure if it was defective or not, but searching the internet other people had similar experiences, swirling garbled audio, regardless of connection. It went back to the vendor, and there is a credit to use up. Still thinking of the Scarlett 2i2 2nd gen, any other suggestions?
  17. Now that I have spent time with voicing the speaker, I haven't worked up the ambition to dial in a crossover on the Behringer DCX 2496, and move to the QSC power amps. Not to mention the other projects on the go! Cold weather puts a damper on working outside.
  18. You just need the right guy to move and install those wooden refrigerators. https://en.wikipedia.org/wiki/Magnús_Ver_Magnússon
  19. From Ethan Winer: http://ethanwiner.com/myths.html Myth: Absolute microphone or speaker polarity makes an audible difference. Fact: While nobody would seriously argue that it is okay to reverse the polarity of one signal in a stereo pair, I've never been able to determine that reversing the polarity of one signal - or both if stereo - ever makes an audible difference. Admittedly, it would seem that absolute polarity might make a difference in some cases, for example, when listening to a bass drum. But in practice, changing the absolute polarity has never been audible to me. You can test this for yourself easily enough: If your console offers a polarity-reverse switch, listen to a steadily repeating bass drum hit and then flip the switch. It is not sufficient to have a drummer go into the studio and hit the drum while you listen in the control room, because every drum hit is slightly different. The only truly scientific way to compare absolute polarity is to audition a looped recording or drum sample, to guarantee that every hit is identical. Important Update: Mike Rivers from Recording magazine sent me a test Wave file that shows absolute polarity can be audible in some circumstances. The polarity.wav file (87k) is a 20 Hz sawtooth waveform that reverses polarity in the middle. Although you can indeed hear a slight increase in the low end fullness after the transition point, I'm still not 100 percent certain what this proves. I suspect what's really being shown is a nonlinearity in the playback speaker, because with a 50 Hz sawtooth waveform there is no change in timbre. However, as Mike explained to me, it really doesn't matter why the tone changes, just that it does. And I cannot disagree with that. More Update Info: After discussing this further with Mike in the rec.audio.pro newsgroup I created two test files you can download and audition yourself. The Kick Drum Wave file (324 KB) contains a kick drum pattern twice, with the second reversed. Play it in SoundForge or any audio editor that has a Loop mode, so you can play it continually to see if you hear a difference. The Voice Wave file (301 KB) is the same but with me speaking, because Mike says reversing polarity on a voice is surely audible. I don't hear any difference at all. However, I have very good loudspeakers in a room with proper acoustic treatment. As explained above, if your loudspeakers can't handle low frequencies properly that could account for any difference you might hear.
  20. Regarding reversed polarity, consider the example of simply using the device for playback: Instead of a forward motion on the speaker diaphragm, you will have a rearward movement. This will change our perception of the sound of a completed system if this is not corrected, especially in the bass, not so much in the region where wavelengths are short, and small head movements will cause many rotations of phase.
  21. I concur, a boom mic stand is a solid investment when it comes to measurement gear. Here is an example from Amazon: https://www.amazon.com/AmazonBasics-Tripod-Boom-Microphone-Stand/dp/B019NY2PKG/ref=sr_1_3?s=musical-instruments&ie=UTF8&qid=1513464419&sr=1-3&keywords=boom+mic+stand I am sure you should be able to source one locally similar to the example. It does not need to be a heavy duty model, and the slimmer the better. ( you do not want reflections from the mic stand to reach the mic capsule )
  22. Also of note, you must ensure that the settings in Windows ( I assume you are using Windows, not Mac or Linux ) match those set in REW ( 2 channel, 44.1 khz ) as these can be set differently, and your results can be wonky. Every time I use REW, I have to change the settings for Windows under the sound device.
  23. Good question, with my duplex sound card, I use a loopback cable, in essence, returning the output of the sound card to the input. The software calculates the round trip latency and deducts that from the signal arriving from the microphone input, thus giving you your delay measurement. On one channel, the microphone is connected, on the other, the loopback cable. Alternately, REW can use a high frequency device to calculate delay. This requires the sweep to be set full range, and it will listen for the high frequency chirp before the measurement. ( Typically only used for full range loudspeakers ) Yes your Marantz has time delay functionality. I am not familiar with Audessey products, and if utilizing it will give you an appropriate delay. Someone more familiar may be able to help you out in this regard. Since the UMIK-1 is a USB device with no other input, you could add a second sound card with just a loop back cable in order to have REW calculate the time delay. In the drop down menus in REW, you have the option of telling the software what inputs and outputs you would like to use. Hope that helps you.
  24. I have done some more research on sound cards, and came up with some interesting information. The Behringer UCA-202 has reversed polarity on both the input and outputs, the only one in the test to exhibit this phenomenon, according to this website: http://www.daqarta.com/dw_gguu.htm Polarity: The Polarity tests were done using a separate scope. The Generator was set to produce a biphasic Pulse waveform, such that the positive phase preceded the negative phase, and there was a dwell time at zero before the next pulse. The output had normal polarity if the positive phase appeared first on the scope. A loopback cable was then used to feed the output back to the input, and if the Input waveform seen by Daqarta also showed the positive phase first, the input likewise had normal polarity. This was the case with all devices except the Behringer UCA202, which inverted both the output and input (which means that it could not have been detected with a loopback alone). Read this thread on DIY audio, might have second thoughts on the Focusrite Scarlett 2i2 sound card. http://www.diyaudio.com/forums/equipment-and-tools/301166-focusrite-scarlett-2i2-2nd-gen-measurements-whats.html This thread has me looking at another Behringer: http://www.diyaudio.com/forums/equipment-and-tools/312454-usb-audio-interface-measurement.html
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