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MickyMcD

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Posts posted by MickyMcD

  1. Stereo In My Wharehouse! Please Help

    in Pro Audio / Home Audio / Home Theatre

    Posted

    What would suit you would be powered speakers. Easy to lift plastic bins that can be placed in position, a signal lead and a power lead run to them and that is all. If you can afford them, my first reccommendation are the RCF TT22A's. They are tough on the wallet, so if that is a concern, try the RCF 300A or the JBL EON or the TAPCO T-15A. The TT22A will be the absolute best performing powered loudspeaker for you, however the latter three will perform quite well in this situation.

    Cheers,

    Mick

  2. Setting The Gain

    in Amplifiers

    Posted

    I'm not sure if you meant Boon was wrong, but just in case you did....

    The reason your input voltage is in direct proportion to your output voltage might have something to do with the fact that an amplifier is an electric device. It has a power supply. Now, let's follow the wrong way of thinking, that input = output voltage. That means that your CPU, HDD, CD, M/board, Keyboard etc etc are all running at either 110 or 240v. Or that amplifiers with an inbuilt Switch Mode Power Supply with Power Factor Correction like a Camco V12 or Powersoft K20 are outputting from 110 TO 240v, depending on what country you are in.

    Once again, no.

    A power amplifier uses its linear power supply to set a vmax and vmin, or maximum voltage rail and minimun voltage rail, which really is just the vmax but in reverse polarity. These vmax and vmin determine the absolute maximum voltage passing through the amplification circuitry. As output is increased, load on the power supply is increased and it supplies current to suit. This current and voltage from the supply powers the power stage of the device to modulate the incoming signal to a high level output signal.

    So, if the power supply is fed by 14.4v, who gives a shit really. It will probably set its vmax and vmin around 50+ volts, determining on the build of the device and how much power it is needed to output. An automotive power supply is just one build to use low voltage and high current to get what it needs, not the reverse for mains powered devices.

    Therefore OP, take your DMM and do set it to 200v, place that on the output terminals of your amplifier and use Voltage Squared divided by Impedance. Just take your voltage on ze output terminal, square it and divide it by your loudspeaker or speaker's resistance. Badah! Instant output wattage.

    Cheers,

    Mick

  3. Setting The Gain

    in Amplifiers

    Posted

    mkornely89, an amplifier does not output a constant voltage from its terminals. What you are implying is that an amplification device is always outputting the input voltage and no more, no less, so that the change in amplitude is simply a change in output current.

    No.

    Listen to Boony. Please. Before you hurt somebody.

    Cheers,

    Mick

  4. Sub Theory?

    in Subwoofers / Enclosures

    Posted

    If your woofer is moving that far, you are simply wasting power. If you can make a driver extrude a full 100mm and still retain acoustic output worth noting, you are doing something incredibly different that no-one has ever seen before.

    Cheers,

    Mick

  5. Brown Note

    in General Audio - Can't find a category for your question? Ask here.

    Posted

    The brown note is very real.....don't doubt it. Personal experience, we were just investigating induced harmonics, in which you are using two different frequencies to create a harmonic of a lower frequency. I can't remember exactly what we were using, but it had the overtone of about 7 1/2 hertz. I had the runs at that point in time and....well, that was an interesting experience at the least.

    Cheers,

    Mick

  6. Some Songs Just Dont Beat. Why?

    in General Audio - Can't find a category for your question? Ask here.

    Posted

    There are a number of methods you can attempt to rectify this situation. My thoughts are you have a box with a frequency response all over the shop, and/or the length of your vehicle with the new woofer placement is not suffecient to accentuate certain frequencies. To rectify number one, try some polyfill around the driver inside the enclosure, a few square feet shall do you just fine. For number two, the only thing you can do is try to move the enclosure, but with an enclosure the size of yours, that may be easier said than done. Low frequency waveforms are very long, and it sounds to me that some frequencies have the mean/average/middle point of the wave sitting square at your listening position, resulting in lower than average pressure at the mix position.

    Then again, maybe not.

    Cheers,

    Mick

  7. What Is Your Likings?

    in General Audio - Can't find a category for your question? Ask here.

    Posted

    And this is why I respect you...

    Flat response 20/20k dude, that's what I am after. Definately interested in your crossover design, especially with PTC's and bulbs, that would be a definate boon. 24db/oct preferable, in Linkwitz/Riley or Butterworth. In terms of loudspeakers, I'd love low moving mass high range and I know I'd cream at ribbon HF drivers.

    But seeing what you've done so far, I'm sure any driver you produce will be of high standard.

    Cheers,

    Mick

  8. Why You Shouldnt Play Vocals Through A Sub

    in General Audio - Can't find a category for your question? Ask here.

    Posted

    playing higher notes to a subwoofer will not cause any damage...like forevrbumpn said...the inductance of the coil is why it doesn't really matter

    Actually aznboi3644, yes it will, under certain set conditions. The car audio environment may not be suspect to these conditions frequently, however it certainly is present. As mentioned before, the coil assembly is not cooling itself down though there is power present in the coil, thus producing heat. Again, in the car audio environment when your mains amplifiers are not quite as powerful as some, this issue is not quite as pressing.

    It is common knowledge however in the sound reinforcement area that crossovers too high on your low frequency drivers can and will cook them. When you are juggling 3k a side and you are putting in 3k of real world wattage into a motor that isn't cooling, you won't be making any noise for a while.

    Also, a lot of it is psychoacoustic. You don't get the results you want in terms of pressure as the driver cannot reproduce these frequencies, so you turn it up. More power to the coil but no real gain in terms of volume. So up it goes some more and more and more until you have breached the specific thermal capacity of that set motor and whoosh, now you have a slinky.

    tl;dr Don't do it. You are putting high power high frequencies into a driver designed to cool through motion and it just ain't moving.

    And cheers to Boon. I run a pair of P.Audio 15" midrange drivers to 1.9khz.

    Cheers,

    Mick

  11. 15's & 18's

    in Subwoofers / Enclosures

    Posted

    An 18" transducer is fine for any sort of transient response you like. If you know what you are doing, you can make an eighteen sound like a fifteen, but not the other way around.

    Anyone that tells you that an eighteen inch transducer is not responsive enough for rock and roll music has never been to a rock and roll concert.

    Cheers,

    Mick

  13. So No Matter What If Ur Amp Is All The Way Up Ur Clipping?

    in Amplifiers

    Posted

    Neel, you are correct in the fact that yes, clipping a power amplifier will damage drivers. But Boon is 100% correct in saying that it's only when you are in serious square wave mode that 'the shit just got real.' An old trick in PA was to let your bottom end amplifiers just clip out that wee bit, just shaving the tops off the wave, instead of letting the limiters go wild. That gave you an extra 2-3db, which can be the difference between a pathetic or excellent mix or sound. Me personally, my method is to use amplifiers with at least double, if not triple the reccommended continuous power handling of the driver, limit it and have a metric dickton of headroom.

    But heavy clipping? You'll be singing 'Puff the broken driver' for a while.

    Cheers,

    Mick

  15. So No Matter What If Ur Amp Is All The Way Up Ur Clipping?

    in Amplifiers

    Posted

    yea i never have it all the way up i was just curious to how u find out when someone is

    Usual Methods;

    1) Oscilloscope. This device will show you a graphical representation of the waveform. A flat, or clipped, top of each positive and negative cycle indicates overdriving of the power stage (amplifier clipping), overdriven pre-amplification signal (source clipping) or some funky-ass synthesizer beats from the 80's.

    2) Audible clipping. When sources clip, it's not so bad for the drivers. But you WILL hear it. It sounds like a harsh, grating sound referred to as unharmonic or harmonic distortion. Unharmonic distortion is common in source overdriving, harmonic is a bit more common as an omnipresent distortion in MosFET devices and overdriven amplifiers. Think of a rock and roll guitar. That is distortion.

    Low frequency distortion is a little bit harder to hear, but it is fairly obvious. You will have a smooth bass note, but once overdriven, it takes on a muffled version of the same harmonic distortion described earlier. This is because amplifier overdrive synthesizes distortion peaks at set intervals of octaves, making it harmonic. If you are clipping out at 50hz, the next octave up is (usually) beyond the frequency response of the driver, and thus sounds muffled and dampened. That and the fact you are clipping the shit out of the waveform, but hey, whatever.

    P.S. Stop being such a rude and arrogant child. Your horrible spelling is either a) incredibly alike to your friend or B) yourself, and your friend was never here.

    Cheers,

    Mick

  21. Capacitors...

    in General Audio - Can't find a category for your question? Ask here.

    Posted

    In all seriousness, you should never need a capacitor. The amplifier power supply should be chock full of high capacitance. A well built amplifier will have enough capacitance and charge to handle zero headroom transients as long as it has a stiff supply of juice. For a well built amplifier, external capacitors are simply not needed. Instead, if the amplifier is not handling said transients well, stiffen the supply voltage.

    That being said, some amplifiers are built more as absolute raw powerhouses that do have very slight trouble with extreme voltage swings that may in fact benefit from external capacitance.

    Cheers,

    Mick

  22. Spl Difference With Same Power To Different Subs?

    in Subwoofers / Enclosures

    Posted

    But if they were at the same point of excursion, it wouldn't matter would it (I'm not sure that's why I'm asking)?

    Yes, it does. Overall movement of the cone isn't what dictates 'loud' and 'quiet.' In fact, you will notice that for extreme SPL bursts at the enclosure and vehicle resonant frequency, the driver really isn't moving too much at all.

    So let's look at it this way. You have a woofer that is 2.4% effecient with respect to both electrical and mechanical factors. You put in 1000w, you get 24 acoustic watts of sound out of it (hypothetically.) You have a woofer that is 5% effecient with the same 1kw of power, you have 50 acoustic watts of sound. BIG difference in overall sound pressure level.

    Your situation may not be that extreme, but the point I am trying to get across is that a more sensitive loudspeaker system, that is the enclosure, damping, driver, tuning etc will most likely (ie 95% chance) be louder. Whether that be .1 decibel or 1 decibel difference, I don't know.

    Cheers,

    Mick

  24. Ive Looked Everywhere

    in Amplifiers

    Posted

    I got slightly under rated power @ 2 ohm driving the AP-15Bl. Rated is 950 watt, to be safe I left it pushing about 40 volts, around 800 watt @ 35hz. But, distorting slightly, it would do it's rated at 2 ohm, 35hz. I can't tell you how it performs at other impedance loads, but I like it.

    Cheers,

    Mick

  25. Ive Looked Everywhere

    in Amplifiers

    Posted

    I disagree with Big P. I chucked in an AP15001D and a TXX-AP15BL in a friends car and it goes great guns for what it is. We did get them cheap, but I find the AP15001D to be worth the money he paid for it. Good little amplifier.

    Cheers,

    Mick

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