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TD-9 headphones output level low?

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  • TD-9 headphones output level low?

    I mentioned this in the headphones thread (saying I had to put the output level to over 75% to get a decent soundlevel using my Sennheiser 280 pro's. Turning it all the way up to the max still isn't what I expected.

    I just bought a Sony MDR-V700DJ and don't think the sound is a lot louder than the Sennheiser's (in the music store it did sound louder than the AKG's and other type of Sennheisers). According to the specs, the impedance of the Sony is much lower than the Sennheiser (24 db verses 64 db). So the Sony has much less resistence and should produce a lot more sound, right? Then why doesn't it? As said, the sound level of my Yamaha CVP-303 digital piano output is really a lot louder.

    Is this the same for the TD-12 or TD-20? Anyone else with this problem?


    BTW: I'm not deaf by any means. In fact I'm known for hearing just about the slightest sound. So that's not the answer.

  • #2
    The db really doesn't matter. What impedance are they running? I'm guessing something low so I'm guessing the TD-9 probably runs a higher impedance. [like studio gear] So you would want to try some cans that are higher and closer to matching in impedance.
    Alan
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    • #3
      FWIW, I looked up several Roland and Boss products and it seems that the "average" headphone out impedance runs somewhere around 100-140 ohms. [Roland] A lot of the Boss stuff runs lower around 30-60 average; so yes, you will need to find some headphones that have a higher impedance.

      ALTERNATIVELY, this could be something as simple as internal volumes turned down. As I am not familiar with the TD-9 yet, have you checked this posibility?

      Not many people I talk to are very ecstatic about Sony headphones. Some love them, but when I get similar questions from customers that are describing 'muffled' or 'low volume' issues, I can usually guess correctly that they own some Sony's.

      Oh, and you've got the "resistance" thinking backwards. It's actually harder to drive lower impedance headphones. That's why you need to get closer to matching.

      edit: The only numbers [output] I can find for the TD-9 [and other modules] say 1.0k ohms... if I read that correct, that's super high - like studio level. [usually 600+] The HD-1 is 100ohms.
      Last edited by Alan VEX; 06-03-08, 03:38 PM.
      Alan
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      • #4
        Originally posted by amonline View Post
        Oh, and you've got the "resistance" thinking backwards. It's actually harder to drive lower impedance headphones.
        I think it depends what your definition of harder/easier is, but isn't lower always louder?


        Bruce

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        • #5
          For general consumer electronics, yes; but not always for pro audio level gear. His headphones probably work fine with iPods and such. The dependant factor is the best range. In this case, something higher will be louder as it will match better.
          Alan
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          • #6
            Match what? 600+ to 1.0k ohms?


            Bruce

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            • #7
              He won't match it, but he can go higher which will produce the same results. The bottom line is to get the impedance closer than it is. These are DJ headphones afterall. They are designed for listening to stereos, not actual musical equipment.

              Sony's tend to sound 'muffled' to many people at the same time. Raising the number will most likely help. I don't know if you've ever looked at the numbers, but real studio headphones are generally 50ohm and up. Sony does it in reverse for some reason and I guess it's kind of a web myth about the 'lower number' thing. I've thought the same thing in the past until I started reading actual audio forum geek threads. Sony's are generally the headphones I always read/hear/get complaints about.

              I'm sure there's more to it than what I'm saying and I'm sure that sensitivity plays into that at the same time. I'm definately no expert on this. I'm just going by what I've read from reputable sources. It must be right if all the top of the line studio cans fit this profile.
              Alan
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              • #8
                Because studio headphones need to be loud?


                Bruce

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                • #9
                  Here's a few tech notes on headphones and impedance. I'll try to word it in an easy to understand manner but that isn't always easy.

                  In the world of headphones, there are four main factors that typically determine what headphones will suit what outputs.
                  These factors are current, voltage, wattage and impedance.

                  * Impedance is the amount of 'resistance' or 'load' presented. The higher the number, the less the load (but not necessarily louder as explained below).
                  * Voltage is, in this case, the amplitude of the signal, measured in Volts.
                  * Current is the strength of that signal and how capable it is, measured in Amps.
                  * Wattage is the total power if the signal and is obtained by multiplying Volts and Amps together.

                  As you can see, it is the wattage that will determine the overall capability of the headphone amplifier. A high wattage amplifier (ie lots of volts AND amps) will be able to drive any headphones to a loud level.

                  OK then, why the variation? Why not just make an amplifier that can drive all headphones to a loud enough level?
                  Cost! It is easier and cheaper to make a lower wattage amplifier.

                  It is also easier to make an amplifier with a high voltage swing but low current capacity which is fine for driving high impedance headphones. Such headphones require less effort (current) to drive them and will present less of a load to the amplifier. Perfect for a high voltage, low current amplifier. Such amplifiers are common amongst semi professional equipment driven from mains power (ie from a wall socket) because there is plenty of voltage present from their power supplies.

                  Low impedance headphones were created when battery powered equipment became popular. The higher voltages found in mains powered equipment were not available from a couple of batteries so low voltage, high current amplifiers were created which can drive low impedance headphones perfectly. Remember, low impedance headphones require less voltage but more effort (or current) to drive them.

                  Now we have a situation where there's both low and high impedance headphones on the market and both mains and battery powered equipment too.
                  If we plug low impedance headphones (requiring low voltage and high current) into an amplifier designed for high impedance loads (high voltage, low current), these headphones will load down the amplifier reducing its voltage 'swing' and therefore reducing the output level.
                  If we plug high impedance headphones (requiring high voltage and low current) into an amplifier designed for low impedance headphones (low voltage and high current), the amplifier won't have the voltage swing necessary to drive these headphones and, once again, low level.

                  What can be done to fix this?
                  There are two possibilities and the first was mentioned earlier by Alan and that is to find out the recommended impedance for the item (in this case the TD9 module) and buy headphones to suit it. Not having the specs on hand, I am not sure what it's rated impedance is.
                  The second possibility is that the manufacturer has designed the amplifier to drive all impedance headphones. These amplifiers are typically only found in top of the line studio and professional equipment where manufacturing costs are not an issue. These devices typically have headphone amplifiers capable of both high voltage AND current (which equals higher wattage) and can drive any headphones.
                  Care must be taken using such amplifiers with low impedance headphones because they will be capable of VERY loud levels and can easily damage hearing!

                  I have used both high impedance headphones (my AKG K240's) and low impedance headphones (various DJ models) with my TD20 and it is more than capable of tearing my ears off with either!!
                  My AKG's are next to useless on battery powered equipment though because they are designed for professional use and these battery powered devices do not have a high enough voltage swing to drive them properly. However, I bought them for studio use so that is not a problem. I also bought a pair of AKG low impedance 'bud style' earphones for my mp3 player which are designed for portable battery powered equipment.

                  I hope this rather long winded post helps to answer your questions without confusing things too much!

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                  • #10
                    Here's a great artical about impedance
                    I think the chapters about the 600Ohm standard and bridging inputs are germain to this discussion.
                    http://www.soundonsound.com/sos/Jan0...ceworkshop.asp
                    sigpic

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                    • #11
                      Thanks SP for your reply, that explains a lot and thanks Michael for the link, I'll dig into that when I've some spare time. Amonline already added this: the specs of the TD-9 state: Output Impedance 1.0 kΩ, don't know if this for the headphones output, the output jacks or both. And I meant ohms of course for the impedance not db.

                      Amonline, I tried the Sony in the story, only able to hear their music. Using the TD-9 sound i good, but using my digital piano I also have to describe the sound as muffled. The Sennheiser sound more 'open', more low and more, less muddy in the middle.

                      So I guess I'll have to find some other phones with higher impedance.

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                      • #12
                        I guess it is possible but 1KΩ sounds more like an output jack spec than a headphone jack spec to me.
                        I would expect the rated load impedance of the TD9 to be around 100 - 150Ω or lower given the target market but anything is possible.

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                        • #13
                          Correct. Remember, I said this above:

                          I looked up several Roland and Boss products and it seems that the "average" headphone out impedance runs somewhere around 100-140 ohms. [Roland]
                          Alan
                          ---------------------------------------------------------------------------------------------------------
                          website | youtube | facebook | group | newsletter | message | recommendations

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                          • #14
                            From what I read I also thought that 1KΩ would be the impedance of the output jacks. So then I have to find headphones which match the impedance of the TD-9 really close, but I have to guess what the impedance is? Doesn't make a lot of sense.

                            I looked up the impedance of the AKG 240: 55Ω, more or less like my Sennheiser 280 pro (64Ω). But, as said, when I turn the sound level to the max, it's absolutely not deafening loud. So what's the explanation for that? And what headphones or which impedance for the headphone would Roland suggest for use with the TD-9? Anyone has a link to a site were you can compare Ω's?

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                            • #15
                              Originally posted by eric_B View Post
                              From what I read I also thought that 1KΩ would be the impedance of the output jacks. So then I have to find headphones which match the impedance of the TD-9 really close, but I have to guess what the impedance is? Doesn't make a lot of sense.

                              I looked up the impedance of the AKG 240: 55Ω, more or less like my Sennheiser 280 pro (64Ω). But, as said, when I turn the sound level to the max, it's absolutely not deafening loud. So what's the explanation for that? And what headphones or which impedance for the headphone would Roland suggest for use with the TD-9? Anyone has a link to a site were you can compare Ω's?
                              AKG make 240's in two different impedances. Mine are the 600Ω 'Monitor' version designed for studio use.
                              It looks like you'll have to call Roland to find out the specs. One thing I can say is my 600Ω K240's are too loud at just over half volume on my TD20 and that is with the faders at half. It would be far too loud with the faders and the volume at full!!

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