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Impious

SSA Tech Team
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Everything posted by Impious

  1. Found this guide on another forum, and given the slew of recent threads on troubleshooting noise, thought I would post it here. One word of warning is that some HU's and/or processors nowadays have a zero bit mute, which essentially cuts off the output during low signal passages to reduce noise.....so be aware if this is a feature your unit has. Onward to the guide; How can you eliminate alternator whine in a car audio system? If you have alternator whine in a car audio system and want to get rid of it, there is only one sure-fire way to do it. David Navone and Richard Clark from Autosound 2000 in the USA developed the following step-by-step instructions. If you follow the instructions EXACTLY, you are guaranteed to trace and eliminate the noise in your car audio system. Don’t miss a step and don’t assume that something is OK without checking it. Each time you check for noise, you should do it with the engine running at 1500 to 2000 rpm and the headlights on full beam so that the alternator will be charging. The tests with the CD player connected should be done with a ‘zero bit’ track playing and the volume at maximum. Set your CD player to ‘repeat’ if it has that feature. Safety. Make sure when doing noise tests that the parking brake is on and working, and that the vehicle is in neutral or ‘park’. Perform these tests in an area with good ventilation or use an extension hose on the exhaust to route the fumes outside. Step 1. Check the Amplifiers 1a. Unplug the RCA cables from the amplifier/s and mute the signal at the input by using shorting plugs. This will isolate the amplifier from the rest of the car stereo installation. You can make shorting plugs by taking cheap male RCA plugs and soldering the centre and outer terminals together. This shorts out the input of the amplifier/s to ensure that it has zero signal. Has the noise gone? Yes. Go straight to Step 2. Reduce The System. No. Go to 1b. 1b. Disconnect the speakers from the amp and connect a pair of test speakers to it. Make sure the test speakers are not in contact with the car body. The purpose of this step is to ensure proper isolation of the speakers and the speaker leads from the car's chassis. Has the noise gone? Yes. Check speakers, speaker leads and passive crossovers for proper isolation from the car's chassis. Shift passive crossovers to a location away from power cables and the car’s body. No. Go to 1c. 1c. Isolate the amplifier from the chassis of the car. There must not be any electrical contact between the car's chassis and the amplifier, except for the grounding point. Has the noise gone? Yes. Reinstall the amplifier isolated from the chassis of the car. Make sure that the amplifier is grounded in just one point. No. Go to 1d. 1d. Supply the amplifier with an isolated power source, for example an external car battery or a 12-Volt DC power supply. Has the noise gone? Yes. Noise is entering the amplifier via the power supply, try changing the grounding point and add external power supply filtering. Consider changing the amplifier. No. The amplifier has some severe problems, is totally isolated and still noisy. Replace it or have it repaired. That is the end of Step 1. You have now either eliminated the amplifier and speakers as a problem or you have replaced a faulty amplifier. Now you can go on to Step 2. Step 2. Reduce the System. 2a. The amplifier is known to be OK. It is now time to disconnect any signal processors (equaliser, electronic crossover, etc.) and connect the signal from the output of the head unit directly into the input of the amplifier. Has the noise gone? Yes. The noise source must be either one or more of the processors or possibly the signal route. Go to Step 3. ‘Add Signal Processors’. If you didn’t have any signal processors and you are using the signal cable in its normal, installed route then the problem is solved. No. Go to 2b. 2b. Run new signal cables over a new route between the head unit and the amplifier. Has the noise gone? Yes. Permanently route the signal cables in the new route. Go to Step 3. ‘Add Signal Processors’. If you don’t have any signal processors then your problem is solved. No. Go to 2c. 2c. Isolate the case of the head unit from car's chassis. There must not be any electrical contact between the head unit and car chassis except for a single grounding point. Beware of antenna grounds and pullout cases! Has the noise gone? Yes. Reinstall the head unit isolated from the car's chassis and any other metal parts in the dash. Ground the head unit at one point. Go to Step 3. ‘Add Signal Processors’. If you don’t have any signal processors then your problem is solved. No. Go to 2d. 2d. Move the head unit ground to a quieter grounding point. Test a number of points and also try grounding the head unit to the same point as the amplifier. Has the noise gone? Yes. Reinstall the head unit using the quiet grounding point. Go to Step 3. ‘Add Signal Processors’. If you don’t have any signal processors then your problem is solved. No. Go to 2e. 2e. Move the head unit as near to the amplifier as possible. Then connect output of the head unit to the amplifier with the shortest possible RCA cables. Has the noise gone? Yes. Reinstall the head unit one step at a time. Check for noise after each step during the reinstallation. Once you have the head unit installed, noise free go to Step 3. ‘Add Signal Processors’. If you don’t have any signal processors then your problem is solved. No. Go to 2f. 2f. Supply the head unit with an isolated power source, for example an external car battery or a 12 VDC power supply. Make sure that car chassis is not in contact with the head unit. Has the noise gone? Yes. The head unit is sensitive to noise in the supply voltage. Add power supply filtering to the supply voltage for the head unit or use an isolated power supply. You may be better to change the head unit. Once you have a head unit installed noise free, go to Step 3. ‘Add Signal Processors’. If you don’t have any signal processors then your problem is solved. No. There is a serious problem with the head unit. Go to Step 4 'Check the Vehicle' and/or change the head unit. Step 3. Add Signal Processors. At this level the amplifier is known to be good. The car's electrical system is OK and the reinstalled head unit is working fine when connected directly to the amplifier. 3a. Connect one of the Processors back into the signal path. Has the noise gone? Yes. Go to 3a for the next processor. If there are no more processors, the problem is solved. No. Go to 3b. 3b. Run new signal cables over a new route between the Head-unit and processor and between the Processor and the amplifier. Has the noise gone? Yes. Permanently route the cables on the new quiet path. Go to 3a for the next processor. If there are no more processors, the problem is solved. No. Go to 3c. 3c. Isolate the processor from the car's chassis except for a single grounding point. Connect the processor ground to the same grounding point as the head unit. Has the noise gone? Yes. Provide isolation between the Processor and the car's chassis and permanently route the cables on the known quiet path. Go to 3a for the next processor. If there are no more processors, the problem is solved. No. Go to 3d. 3d. Since new cables and re-grounding does not help, it is time to relocate the processor very near the amplifier. Connect the output of the processor to the amplifier with the shortest possible RCA cables. Has the noise gone? Yes. Reinstall the Processor one step at a time. Check for noise after each step in the reinstallation. Be careful when routing the signal cables. Remember that the car's chassis is a conductor. Go to 3a for the next processor. If there are no more processors, the problem is solved. No. Go to 3e. 3e. Power the processor with an isolated power supply. Do not let the processor touch the chassis of the car. Has the noise gone? Yes. The processor’s power supply in not sufficiently isolated from its audio circuitry. Either replace it or consider the permanent installation of an isolated power supply (1:1 DC/DC converter). This type of device provides a permanent power source that is well isolated from the car's chassis. Go to 3a for the next processor. If there are no more processors, the problem is solved. No. Go to 3f. 3f. Physically separate the processor and the isolated power supply from the rest of the system by many metres. Use long signal cables. Has the noise gone? Yes. Something is seriously wrong with either the processor or your install/test procedures. Please repeat this level from the beginning. No. Change Processor -- this one has design problems. Go back to 3a for the new processor. Step 4. Check the Vehicle The suspect car's charging and electrical systems can be checked by using the previously installed sound system in a "known quiet" car. 4a. Connect jumper cables between the batteries of the two vehicles and start the engine of the suspect car. Turn on the headlights on the suspect car and listen to the stereo on the "known quiet" car. Is there now noise in the quiet car’s system? Yes. Have a qualified auto electrician check out the car’s charging system. No. The suspect car's alternator and charging system is now proven to be quiet. The problem must lie in the car stereo installation -- not in the vehicle.
  2. So I'm rocking a 46" Panasonic Plasma 720P that I bought from Circuit City in probably 2007'ish. Its basically the flip phone of TVs. Finally looking to upgrade. 55", TV (digital over the air) and movies (streaming HD, bluray) only. No gaming. Price point under $500. From everything I can find, something like the TCL S515 seems to be the best bang for the buck. Any cheaper but equivalent options, or better options at the same price point?
  3. Impious

    The 7empest

    Thanks! I'm really enjoying them.
  4. Impious

    The 7empest

    I've had these speakers sitting around for *literally* a decade, finally decided to actually build them into something MTM using Exodus Anarchy and Seas 27TDFC. Enclosure is 2cuft tune to 35hz. They should dig down to 30hz with ease, so we'll see if I add a sub or not. The baffle will be removable so that I can easily access the crossover, reuse the enclosure with different speakers or reuse these speakers in a new enclosure. I had debated on active vs passive but I'd done active in a car for years. I've never designed passives from scratch since I didnt play too much in HA/HT, so it's an experience I'd like to try. I'm intrigued by the combination of art and science that goes into the design of a passive network. My audio skillz are a bit rusty, so the task is a bit daunting. But I'm relearning pretty quickly...I think? Every DIY project needs a name, right? Decided to call these 7empest. Why? Well, primarily because TOOL is the most badass fucking band ever. If you don't understand the reference GTFO my thread (no, seriously....go). It works because the Anarchys are 7" drivers, and what does a tempest cause? Anarchy. See. It works. My woodworking skills leave a lot to be desired. Right now as long as these are simply functional I'll be happy. Baffles turned out nice though About the only thing that's gone right so far. This is where we're currently at.
  5. Impious

    The 7empest

    Welp, spent some time today building and measuring crossovers. I think I built six different iterations in total, and took countless measurements of each one. Here are, I think, the top 3 contenders. The maroon so far looking best on paper for both FR and phase. I did spend a bit of time the past day or so listening to the first crossover I was able to build based on the parts that arrived (some of my inductors were on back order and just arrived today). Made me wonder why the hell I wasted so much time and effort trying to obtain good audio in a car when home audio sounds infinitely better with much less time and money invested, LOL. I really enjoyed how they sounded with that first crossover, and it didn't measure quite as well as these (well, maybe a little better than the purple xover...but I want to give that design a listen so I kept it in my "top 3"). So long story short there I think I'm ultimately going to be very happy with how these turn out regardless These measurements were done in-room, so ignore 300hz down. I'm also pretty suspect of the peak in the last octave from 10khz -20khz, but considering my age and past listening habits I'd be lucky if I can even hear most of that octave anyways. But regardless, all 3 xovers are within +/- 2db from 300hz on up, which is pretty good. Graph "looks" a little ragged but that's because we're zoomed in pretty close. If I zoomed out one or two clicks on the graph it'd "look" much more smooth. Reverse nulls aren't amazing, but I think they're sufficient (maybe a little less so on the purple trace but again, I just really want to listen to that one). Then I have the individual roll offs.
  6. Impious

    The 7empest

    And, it's alive! I literally spent HOURS figuring out why I had no tweeter on the right channel. Finally came to discover that one of my jumper wires were bad It was incredibly frustrating trying to track down the issue, and I dont handle frustration well. Curse words were said (and muttered, yelled and spewed)
  7. Impious

    The 7empest

    Thanks I measured in REW with a Dayton EMM6 mic and M-audio Mobile Pre mic preamp. Z curves were taken in Limp. Modeled the xovers in a mix of Xsim and WinPCD. Those graphs and schematics are from Xsim because at the time I couldn't figure out how to model the tank filter in WinPCD (although I've since figured it out).
  8. Impious

    The 7empest

    Both. The other measurements were all done outside. I'll probably measure these inside just to make my life 183x easier. I should have all the parts in by tomorrow. And I happen to have Mon and Tue off as well So I'll probably spend most of the next 4 days demo'ing and measuring them to see what ends up working in reality
  9. Impious

    The 7empest

    Here's probably one of my top contenders as far as phase and response go. 4th order on the woofer with a zobel and tank filter, tweeter is second order. My last crossover is just a variant of this - slightly different values for some of the inductors and caps to shape the response a little differently. But overall layout is the same. I have a 5ohm resistor on the tweeter to drop the response a little to keep it from being on the bright side, but I am also going to try a 4ohm which would bring the response from the tweeter up to pretty close to flat. We'll see which way sounds best in reality.
  10. Impious

    The 7empest

    So with a little help I came to realize that the dip in my initial measurements from 2-3khz was likely an issue with my measurement system somewhere. So I went through and created a new cal file to basically pretend it didn't exist My new initial measurements look a little different than above, but eliminating that dip in the tweeter response is really the main difference. Spent way more time than I care to admit working on different xover sims, but I learned a bit each time. I'm far from an expert but definitely better than when I started a few weeks ago. Came up with 3 main xovers that I'm going to try. This is probably my favorite. The response isn't the flattest, and the reverse null isn't the best of the bunch...but it's the only alignment that is a 2nd order on both the mids (with a tank filter) and tweeter so the part count is the lowest and it's the simplest design. I think there's something to be said for simplicity. Guys like Zaph and Jeff Bagby (RIP) always tried to design with the least parts possible. I have $160 worth of crossover components on their way to me from PE. to try all three designs. So hopefully out of that I'll be able to make something that sounds decent I just went with non-polarized electrolytics for the caps because, well, they were 1/10th the cost and I'm a tight ass with money, the actual sonic differences are arguable at best, and I may have something in the next couple months that'll require some cash to fund properly. We'll see.
  11. Impious

    Building Custom Subwoofer

    I think what you are missing is that companies like Stereo Integrity work with a build house or with vendors who do large order OEM only production runs. If you want to build 1000 drivers, they'll work with you. If you want to buy 2 VC's, spiders or cones from them, they likely won't even bother responding to your email. The guy who used to run PSI Car Audio was named David and was one of the main guys at the old RE. They have the option to request a custom built sub. https://psicaraudio.com/request-form/ He also ran https://fixmyspeaker.com where you could buy custom parts/recone kits but there is a header that says they aren't taking new orders. Anyways - my suggestion would be to either request a custom sub through PSI and ask if they can ship it unassembled, or see if he can or can direct you to someone who would be willing to just sell the parts.
  12. Impious

    The 7empest

    Yeah it's a little odd. But honestly now that I'm working on the xover I'm not mad. On the woofer side the response is flat down to 30hz with an F3 in the mid 20's. I can live with that
  13. Impious

    The 7empest

    Okay so I guess this is the starting point for the FR. We will see how it goes from here Also that hiccup at what turns out to be approx 120hz in the Z graph shows up as a -1db dip in the FR response :/
  14. Impious

    The 7empest

    Here's the impedance sweep for the Anarchy's. Learned a few things: 1) For some reason tuning ended up being 25hz instead of 35hz? No idea. I know it's not a measure twice, cut once issue with building the cabinets. Measurements there are solid. I figured I'd be off a few hz one way or the other....but 30% was a little unexpected. I'd considered that maybe it's an accuracy issue with the measurement....but the Anarchy's are infamous for having a cone resonance around 4200hz which is about spot on in the measurement. So.... 2) I had poly fill stuffed in the bottom of the enclosure to start but when I started measuring impedance I had a nearly non-existent impedance peak at tuning. Removed the polyfill and the impedance peak looks much better than how it was. 3) I knew about the hiccup at ~4200hz which is a cone resonance. Not sure what's going on at 150hz...enclosure resonance maybe? Internal reflection? Not sure. Anyways. I had the FR sweeps all done, but going to rerun the sweep for the Anarchy's without the polyfill since based on the Z curve I'm going to be leaving that out.
  15. Impious

    The 7empest

    Got my impedance measuring jig soldered up today Pretty happy with how it turned out considering how long it's been since I've soldered anything
  16. Impious

    The 7empest

    Can at least start FR sweeps tomorrow....finally
  17. Impious

    The 7empest

    Seat padding from the craft section of Walmart It's 1" thick open cell
  18. Impious

    The 7empest

    Welp, as usual this shit is taking way longer than I anticipated. Didnt help I had to spend all day Sat fixing my dryer instead of working on my speaker project But, progress was made. Got my binding post plates installed, baffle mounting bracket pieces put on, holes drilled and countersunk, T nuts installed and started on the cabinet damping. Also realized I forgot about needing to measure the impedance curve....really wish I'd thought about that when I placed my order at PE >:(
  19. Impious

    The 7empest

    I thought about ditching the Seas and just going with the Apollo's, but I wanted to try my hand at designing the network. Who knows, this may turn out to be an epic fail and I'll go that route instead Just placed my PE order for my binding post terminals, a couple caps, T nuts and a few other things. Should arrive in just a couple days, so the cabinets should be in a position to start running FR sweeps this weekend or 1st of next week. I may need a bit of help from Sean when I get to that point. It's been a minute LOL I also learned that if you drop some items in your cart @ PE and leave them there without checking out, PE will email you a coupon for 10% off after a day or so
  20. Impious

    The 7empest

    I have 1 set of the 306P 6.5" mids left. Thought about grabbing a cheap tweeter and turning them into a little bookshelf speaker for my gym if this turns out well.
  21. Impious

    Welcome to the IHoP v.2

    Man 2 months ago those powerblocks were worth more than gold.
  22. Impious

    Welcome to the IHoP v.2

    My wife was giving me a hard time about how much it cost. I told her it'll be the last bar I'll ever need to buy. I need to buy some more 45's and I'd like to upgrade my Fitress Gear bench to a Rep. But otherwise I should be pretty set. For now. I think LOL
  23. Impious

    Welcome to the IHoP v.2

    Bought everything I'd need to install a system in my Durango last summer. Then when it came time to start installing it all realized I have zero motivation to do so. 78% feel like selling it all to replenish what I spent on the home gym, 22% of me still fantasizes about having a badass stereo. I've had a sextuplet of Exodus Anarchy's sitting around unused for literally 10 years. Might turn those into something for the house to see if it squelches the audio bug for me.
  24. Impious

    Welcome to the IHoP v.2

    Don't have a pic of the whole setup but here is my sexy new bar.
  25. Impious

    Welcome to the IHoP v.2

    Built a home gym during the pandemic Holy shit that is a more expensive hobby than audio.
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