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Post by BradM on Jul 2, 2017 12:19:21 GMT -6
I have been getting organized and formulating my test plan. I decided that I'm going to have to do the tests in phases since it's a bit of an undertaking that will require me to design a couple boards/jigs to help me take accurate measurements for some of the things I want to do. But I figure I'll start with noise since that's a little more straightforward. I started making preliminary measurements and working out the kinks in my test setups. Looks like I'll be getting my ass schooled in measurement techniques this summer. :0 If anyone following along has an AP rig or a Prism dScope and would like to pass along some best practices I'd be most appreciative.
Brad
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Post by Martin John Butler on Jul 2, 2017 15:51:17 GMT -6
Brad, maybe by the time your finished with your tests, I'll be ready for a lunchbox, and can make a more informed decision. :-)
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Post by Ward on Jul 3, 2017 6:28:41 GMT -6
This thread is quite a chore to read.
Someone PM me a conclusion, please.
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Post by BradM on Jul 3, 2017 10:40:01 GMT -6
This thread is quite a chore to read. Someone PM me a conclusion, please. I'll be posting a blog post on my website when I have something ready. I'll likely send out a notification to those on my mailing list. Brad |
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Post by Ward on Jul 4, 2017 6:00:13 GMT -6
This thread is quite a chore to read. Someone PM me a conclusion, please. I'll be posting a blog post on my website when I have something ready. I'll likely send out a notification to those on my mailing list. Brad Please post a link for those of us who are interested in cutting through the chafe to get to a conclusion. |
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Post by BradM on Jul 4, 2017 12:28:48 GMT -6
I'll be posting a blog post on my website when I have something ready. I'll likely send out a notification to those on my mailing list. Brad Please post a link for those of us who are interested in cutting through the chafe to get to a conclusion. I'll definitely be sure to do that! I've been spending the weekend taking lots of measurements. It's slow going since each measurement takes 5-10 minutes to do. And then certain findings lead to questions, which lead to more tests. Brad |
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Post by Deleted on Jul 4, 2017 12:50:45 GMT -6
Brad,
I'm very interested in the process you're undertaking to reach your conclusions. I'm up to reading as much as you can post here.
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Post by BradM on Jul 4, 2017 15:48:53 GMT -6
Brad, I'm very interested in the process you're undertaking to reach your conclusions. I'm up to reading as much as you can post here. Coming up with the process is a process.  I've been thoroughly documenting everything. Instead of just dribbling out everything in a series of forum posts, I think it will be easier for me to just post a monster white paper. Then everyone can pick it apart. Brad |
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Post by Deleted on Jul 4, 2017 16:43:02 GMT -6
Brad, I'm very interested in the process you're undertaking to reach your conclusions. I'm up to reading as much as you can post here. Coming up with the process is a process. I've been thoroughly documenting everything. Instead of just dribbling out everything in a series of forum posts, I think it will be easier for me to just post a monster white paper. Then everyone can pick it apart. Brad True. Or, you could seize the very organic opportunity to boost your site's SEO by documenting each small step in blog posts and then boil it all down into one big white paper. Personally, I'd rather read about it in a "play by play" format where I feel like I'm experiencing something along with you than just reading about your experience and conclusions in hindsight. But that's just me. I like tech talk, especially concerning audio, but the last time I sat down to read a big white paper (The Townsend Mic), I got so bored out of my skull because it was written so dryly (any read over 5 minutes, I need a decent narrative) that I closed the window and decided it was easier to just not to buy the mic. LOL. |
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Post by BradM on Jul 4, 2017 20:21:27 GMT -6
@myn - You're totally right. These are excellent ideas. I do agree with this approach and I want to do this. I'm just trying to figure out what the overall story is going to be and then how I want to break that story up into bite size chunks. I do know that the first post will probably be an overview of what I'm trying to test and why, and what is being test. Then the second post will be all about noise. Actually based on what I've learned so far this may be a series of posts. Subsequent posts will be about other tests like the audio quality, power rail impedance, and whatever else strikes my fancy. Right now I'm in preliminary data collection mode. I just want to make sure that all the mistakes are made on my own time privately before there is an audience following along. Clearly I'm not part of the Facebook generation.  I do hear what you are saying, and will take the comment about losing the reader's attention with too much length to heart. thanks! Brad |
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Post by NoFilterChuck on Jul 5, 2017 10:26:01 GMT -6
don't waste time with blog posts. Make blog posts that just show a youtube video of your findings. That's way more interesting to watch vs reading. reading is so 20th century.
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Post by BradM on Jul 5, 2017 11:10:41 GMT -6
That's an interesting idea. I think I could do that in addition to the blog post. Hmmm...
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Post by Deleted on Jul 5, 2017 12:07:51 GMT -6
Sounds great. One last thought. Just going back to purely SEO-related reasons, video is great and definitely helps search because of the importance of video to the consumer, but text is key for when Google crawls your pages (especially since it doesn't quite parse what you say in the video without a transcription*). So doing both is even doubly-better! You run a business that creates 500 series modules so this type of thing can help funnel traffic your way because on one level or another, Google will identify you as someone with expertise and Google prefers "experts" when it comes to Search Ranking.
What you can do is marry your video to the text post where the text is complimentary to what you say in the video,
* Or you can shoot the video first and have the audio transcribed and post the transcription both in the blog post and (for extra SEO zing) into the video itself (there are tutorials on how to do this if you've never tried it).
And of course, the more posts you can spread it across (and making sure they are all cross-linked together, including your videos), the more times each Google crawl of your site crosses those links that bring it back to more your links, etc, etc, the more SEO juice you get as an authority, which is highly beneficial because Google's algorithm will rank information above marketing.
Either way you present the info, Brad, I'll be there to check it out and try to learn what you learned from this experiment.
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Post by BradM on Jul 5, 2017 12:36:31 GMT -6
I really appreciate all the tips and help! I'm such a newb when it comes to that stuff. My brother just laughs at my internet ignorance. I may have to contact you privately when the time comes to do all this stuff. I took a bunch of measurements yesterday with my Avedis 2-space rack. As I'm doing it I'm thinking: "wow, the noise floor on this rack is ridiculously low...this thing is a dream". Then I realized that I didn't even have the cable plugged into the XLR output. Doh! Hahaha. thanks! Brad |
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Post by Deleted on Jul 5, 2017 13:14:26 GMT -6
Brad,
Sure thing. Always happy to help folks whose work I wish to see succeed.
However, plugging in cables... that you'll have to work out on your own. LOL.
Best,
M
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Post by BradM on Jul 6, 2017 10:53:33 GMT -6
I really appreciate that. I'm on top of this cable thing today. Haha. Oh yeah...I'm expecting arrival of an API 500-8B Lunchbox and a Lindell 506 Mk2 today. I'm excited. Brad |
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Post by johneppstein on Jul 6, 2017 13:06:24 GMT -6
don't waste time with blog posts. Make blog posts that just show a youtube video of your findings. That's way more interesting to watch vs reading. reading is so 20th century. Personally, in most cases I'd rather read than watch a video. |
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Post by EmRR on Jul 6, 2017 13:17:26 GMT -6
I don't watch videos. Really. Never said I was normal.
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Post by johneppstein on Jul 6, 2017 13:18:04 GMT -6
Something that really ought to be considered - but would be somewhat difficult to test for - is the long term noise reliability of switch mode power supplies. With a conventional linear supply, anything goes wrong it'll generally make itself known by blowing a fuse or failing to deliver power. Switch mode supplies aren't really always like that - not to say that they don't fail outright like a linear, of course they do - but they also develop less immediately obvious problems that don't impede the supply's primary functions but instead cause it to emit an elevated level of RFI or leak RFI onto the power rails. Since this is something that develops over time I don't know how you'd test for it.  |
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Post by jimwilliams on Jul 9, 2017 11:41:06 GMT -6
I did a lot of noise sweeps on my AP some 20 odd years ago on most common studio gear. Most all 'pro'audio' gear has psu residuals at 120 hz. Do a noise vs frequency sweep and you see the harmonics.
A good psu here has a pretty flat line, 20~20k hz. -120~125 db is a good zone to see if you have any residual 60, 120, 250 hz AC frequencies. Hiss tends to raise that spec upwards in the upper frequencies but the low end below 500 hz should be -120 db or more. Most can't do it ether because of EE missing chops or bean counter interference.
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Post by BradM on Jul 9, 2017 13:39:43 GMT -6
Something that really ought to be considered - but would be somewhat difficult to test for - is the long term noise reliability of switch mode power supplies. With a conventional linear supply, anything goes wrong it'll generally make itself known by blowing a fuse or failing to deliver power. Switch mode supplies aren't really always like that - not to say that they don't fail outright like a linear, of course they do - but they also develop less immediately obvious problems that don't impede the supply's primary functions but instead cause it to emit an elevated level of RFI or leak RFI onto the power rails. Since this is something that develops over time I don't know how you'd test for it. Excellent thoughts. Yeah, I'm not sure how to test for that stuff either. At least with the external switch mode supplies you can easily replace them or upgrade them should something fail. Brad |
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Post by BradM on Jul 9, 2017 13:43:56 GMT -6
I did a lot of noise sweeps on my AP some 20 odd years ago on most common studio gear. Most all 'pro'audio' gear has psu residuals at 120 hz. Do a noise vs frequency sweep and you see the harmonics. A good psu here has a pretty flat line, 20~20k hz. -120~125 db is a good zone to see if you have any residual 60, 120, 250 hz AC frequencies. Hiss tends to raise that spec upwards in the upper frequencies but the low end below 500 hz should be -120 db or more. Most can't do it ether because of EE missing chops or bean counter interference. Hey Jim, Great to see you popping in. Yeah I'm seeing a lot of harmonics at 120 Hz as well...even with some of the switch mode supplies. What dB scale are you using? dBV or dBu or something else? I have to say that a lot of these supplies I'm testing are just not that quiet in the low end. I'd be curious to get your take when I start posting plots. Some of them don't even have sufficient high frequency filtering from what I can tell. And then of course the noise varies as a function of load. Brad |
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Post by ericn on Jul 9, 2017 14:00:24 GMT -6
I don't watch videos. Really. Never said I was normal. Your not the only one! |
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Post by mulmany on Oct 12, 2017 20:38:01 GMT -6
@bradm, did you come to any conclusions about PSU's and the noise they produce? Sitting here looking at my four 500 series 11 space racks, thinking it would be great to have one large well regulated/filtered PSU for all of them. Thinking 6.6amps per +- 16v rail and 3.3amps for +-24v rails, plus 48v for 44 modules. Four vpr outs and two 51x outs, isolation/regulation between the outputs. Probably talking a 3u case that weights a ton. Or just use a console psu:-) Sorry for the tangent... Started dreaming. svart, new product? |
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Post by ChaseUTB on Oct 12, 2017 21:03:32 GMT -6
Wes Audio has a really good priced 10 or 11 space rack ... I was actually considering going that way ... Supecarrier II $699 @ Sweetwater so prob cheaper elsewhere , 11 spaces ... The super carrier 1 is 10 spots and prob could get that cheaper now due to the new model.. www.sweetwater.com/store/detail/Supercarrier2 |
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I've been thoroughly documenting everything. Instead of just dribbling out everything in a series of forum posts, I think it will be easier for me to just post a monster white paper. Then everyone can pick it apart.
I do hear what you are saying, and will take the comment about losing the reader's attention with too much length to heart.
