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Al.M

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About Al.M

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    Bibbulman

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  1. Would have thought the ear muffs provide greater than that protection and here is an explanation, which shows greater levels of protection from ear muffs.... quote: How does NRR change decibels of exposure? “When hearing protection is worn, your level of exposure to noise is based on the NRR rating of the protection device being used. Keep in mind, however, that while the NRR is measured in decibels, the hearing protector being used does not reduce the surrounding decibel level by the exact number of decibels associated with that protector’s NRR. For example, if you are at a rock concert where the level of noise exposure is 100 dB and you are wearing earplugs with an NRR 33dB, your level of exposure would not be reduced to 67 dB. Instead, to determine the actual amount of decibel deduction applied (when decibels are measured dBA which is the most common), you take the NRR number (in dB), subtract seven, and then divide by two. Given the previous example, your noise reduction equation would look like the following: (33-7)/2 = 13. This means that if you are at a rock concert with a level of noise exposure at 100 dB and you are wearing a hearing protector with an NRR 33 dB, your new level of noise exposure is 87 dB. If you are wearing a product with an NRR of 27 it would deduct 10 decibels (27-7/2=10).” Also, 60Hz @ 110dB is just pure theoretical as in practice listening to music and just about every normal sound source in the human world there will rarely if ever be just a single frequency to contend with. It will nearly always be broad spectrum. So things like a bass note will range from say 20 - 200+ Hz. A single freq tone of whatever 60, 500 or 1000hz etc has nothing in it of itself that one would enjoy as music. You can hear examples of single tones though possibly not perfectly accurate frequencies depending what the iPad, tablet speakers can do at such links as http://onlinetonegenerator.com/
  2. Al.M

    CHINA BANS IPHONE SALES

    See what you mean but even in democracies like Australia you still gotta comply if the government law say so and democracy doesn’t help at that moment. You can appeal sometimes, win loose and can’t pay the fine and court costs, so just pay up if too expensive to fight it.
  3. Al.M

    Best amp/dac on a semi-budget

    This post is better suited in the Portable audio forum for responses.
  4. Al.M

    Holographic Sound Stage Pre-amp

    As mentioned maximise your speaker positioning to bring out best imaging (google Equilateral speaker positioning to see what it means). A $500 to $2k used used preamp budget could easily get you some very good tube preamps that would improve over a mid fi DAC or crap sounding existing preamp. Like anything there are good and bad ones in this category so try some out or borrow them from others. The mid fi DACs doing preamp duties in place of a proper preamp are known to be quite flat sounding among other issues. I’ve randomly plonked $200 - 2000 good used preamps in front of other peoples DAC preamps and it was quite obvious how the sound stage improved. Search for other post topics discussing these issues like DAC vs preamp or similar and there is heated discussion to learn from. Examples of good brands to look for are Supratek, Audio Research, Conrad Johnson, custom made preamps, Pass Labs to name a few etc.
  5. Chest slap or the feeling of as far as I reckon is demonstrated in one of the emails above showing the human stick figure where human biology body sound freq resonance shows the human chest cavity or the muscle diaphragm or combination of the two typically resonates at 63hz thereabouts, not much higher or lower. Chest slap and hearing damage will not only depend on one particular frequency. Worksafe legislation codes and standards about hearing damage safety levels refer to a broad range of the octave frequencies that exist such as in music and a total of that expressed as 85dB Leq (A) over an 8 hour exposure period, see chart below for higher noise levels vs less time exposure (Note: A weighted bell curve, not a flat or linear noise measurement as often mentioned in hifi). Exposure to any high noise environment, commonly concerts, home audio and work related activities will gradually cause loss of hearing permantly over time if you constantly and repeatedly exceed the limits set in the charts below according to hearing health medical sources. 1 in 5 people experience these issues in western countries though not only from loud music exposure, and above 50 years age related hearing loss increases dramatically according the stats. The last chart below isn’t quite right but helps to demonstrate hearing damage for too loud a music environment as the Australian safe noise limit for 8 hours is 85 dB(A), not 40 hours, the rest correspondingly less. The chest slap affect would vary for each person per decibel loudness level depending on your body mass, fat etc. Post edit: Personally I have felt this in concerts emiting a 30m distance from stage to mixing desk level at around 95dB(A) vs above post saying 110dB (no weighting stated so means nothing, but likely to be Z or linear weighting, that might translate to about 103dB(A)) still some ways off my experience at much less perceived hearing loudness.
  6. Here is one link to quiet refrigerators but they don’t mention noise levels. https://www.bestbuy.com/site/shop/quiet-refrigerator https://www.buzzrake.com/cat/kitchen-appliances/product/refrigerators/quiet https://lifestyle.euronics.co.uk/buyers-guide/fridge-freezers/noise-levels/ If you are annoyed by your own noisy refrigerator it’s a good indication too loud and around 30dB bedroom is good when sleeping and 40dB living room is good to aim for. I have seen measurements of peoples houses with noise levels as high as 57dB(A) from fridges and other indoor items. Probably best to look at half dozen models in your price range and scrutinise the specs and look for stated sound levels. Positioning of the fridge can help reduce noise like increasing distance and shield behind a wall etc.
  7. With the 63hz freq in mind and reference to the human body part freq above, I think that’s where we need to be humping the bass curve more in our speaker bass systems. A lot of people are just chasing low as possible flat extension around 20-30hz or higher if the driver can’t do less but chest thumpiness in my experience happens more around 37 - 50+ hz ish. Its still good to try and have both chest thumpiness plus a reasonably low 25 - 35hz response or at least a feeling of that. When I try to model on paper a DIY box ported design I like to shorten the port less than theoretical flat response, which always sounds boring to me and instead achieve a moderate hump in the response above f3 response that is more likely to get chest thumping response. The above is obviously a rudimentery description.
  8. One off them in Gumtree is a teak wood finish M version and actually looks better than ebony, which has very sharp edges prone to damage. The picture above shows them incorrectly toed in, Yamaha says the other way round with tweeters on outer. There was an M version in Gumtree last week for $45 with a woofer damaged and veneer work needed!
  9. There are three pairs right now in the Gumtree. They only rare if you don’t bother to look around for them and snap your fingers, blink and expect to see them in front of you instantly.
  10. Also if you pull out the driver and look for a label it may have the make and model number that could be a direct off the shelf replacement from a standard driver maker like Scanspeak or Seas etc. If so order the driver from a supplier and DIY. On the other hand it might be a customised driver that may not be a direct off the shelf replacement or the label has been taken off to stop the speaker being copied.
  11. A google search indicates many speaker repairers locally so give them a try.
  12. Al.M

    $15k floorStanders?

    Also check to see if VAF in Adelaide have any I93 at $12k or I66 at $8k https://vaf.com.au/products/signature-i-93mkll
  13. Check to see if it’s: 1. Loose wire on the mid somewhere inside or cable socket triwire not linked if it has one in the first place 2. Blown capacitor or resistor in the crossover circuit leg to the mid driver. Look for signs like charring or physical issues though unlikely to see that
  14. For used amps try Yamaha AS2100 and 1100 plus Musical Fidelity etc. Gumtree had a 2100. Also combinations of used preamp and power can be found for the same money like Audiolab 8000 pre and power etc. you coud even put together a tube preamp for $500-1000 and same value power amp depending how old gear you are ok with that will sound like a $5000-10000 rrp new setup.
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