[mshivley]

I recently bought a MinDisc MZ-R900 to work out and jog. So I wanted to by some cans to help it shine. The PortaPro's seem
perfect for the job...except there impeadance is rateat 60. I like
to listen to my music loud. Do you thing the MiniDisc will be able to drive these cans with volume to spare, if not I am open to suggestions? I would like to keep in the $50 to $60 range.

Thanks
Mike

 

[Crazy4Bass]

For an impedance of 60 ohms, yes, I do believe that the Porta Pro's can indeed, be driven by your MZ-R900. Most portable 'phones with 60 ohms are powerful enough and loud enough to be driven by most discmans and mini disc players.

 

[MacDEF]

The 900 should drive them plenty loud. Although I would choose the KSC-35 over the PortaPro. The Portas have a bit too much bass IMO, plus the KSC-35 are more comfortable -- and cheaper

 

[dngl]

pretty much anything can drive the portapros... they're some of the most efficient cans around.

 

[gaineso]

Just be careful about the "Loud" part. You may soon find that nothing is loud enough. You only get one chance to NOT damage your ears.

We want you to enjoy the music for a long time. Turn it down just a little and still be listening when you're my age.

 

[dngl]

or buy a radioshack sound pressure level meter and be 100% sure that you aren't hurting your ears.

 

[lee.watkins]

Actually that's a really good idea! Those things are only $40.. not bad. I'm going to get one!

Quote:

Originally posted by Jon Beilin or buy a radioshack sound pressure level meter and be 100% sure that you aren't hurting your ears.

 

[pedxing]

I tried using the spl meter from radio shack and I it didn't work for me. I tested the SPL of the headphones by placing the meter next to the driver from the inside. I then cranked it up till it was like 70 db average. Then I played the same track on my home system till it was like 70 db too. I compared them both and I found the headphones way too loud. I don't think it works well and its dangerous if you do play it by the numbers.

 

[nallyvaico]

Quote:

Originally posted by mshivley I recently bought a MinDisc MZ-R900 to work out and jog. So I wanted to by some cans to help it shine. The PortaPro's seem perfect for the job...except there impeadance is rateat 60.

Actually, I was about to ask a similar question with respect to PortaPro's impedance. Is it 60 Ohms indeed? I have often come across quotations of 32 Ohms for these. So, where's the truth?

At one site, I even found KSC-35's and Porta Pro's quoted at 60 Ohms, and Sporta Pro at 32 (!) Ohms

Also, as I found out, Sporta Pro's sensitivity is different from KSC and Porta Pro: I think 103 vs 101. So there must be some difference...

BTW, I own both Sporta and Porta, and they do sound different.

 

[lee.watkins]

Well of course. 70db average is way loud. Do you talk to people at 70db average? No. You yell maybe, and certainly not directly into someone's ear. 70db works if it's across the room maybe. Distance does have a big effect.

To start with a number out of context doesn't make any sense, even if a book told you that was a safe number. Different ears have different sensitivities, and those sensitivities vary depending on freqency. If we are to continue listening when we're old-timers, we each need to determine what is too loud for our own ears right now, and set the volume not just slightly below this, but SIGNIFICANTLY below this. Better yet, start from the bottom and see what is the minimum volume you're ears find acceptible. Training your ears for greater sensitivity is certainly better than working in the other direction! Once you've got a realistic reference point figured out, it is then that the db meter can be useful in checking an environment for dangerous levels BEFORE the your ears have experienced the abuse.

Yes I did buy that db meter, and I was pretty shocked how loud my headphones actually were (82db average)! What's scary is that the peaks were significantly more... and I considered myself conservative with the volume compared to most of my friends.

Getting back to standards, I read that 60db is an average baseline for most speech (measured from the mouth sources). Keeping in mind speakers are standing several feet apart. It seems to me that the practice of measuring from a source rather than ambient levels is a deceiving practice. If we are to claim an acurate reproduction of a recording in our headphones, then the volumes we use in our headphones should reflect the average AMBIENT volumes encountered in daily life, not the average source volumes.

Quote:

Originally posted by pedxing I tried using the spl meter from radio shack and I it didn't work for me. I tested the SPL of the headphones by placing the meter next to the driver from the inside. I then cranked it up till it was like 70 db average. Then I played the same track on my home system till it was like 70 db too. I compared them both and I found the headphones way too loud. I don't think it works well and its dangerous if you do play it by the numbers.

 

[lee.watkins]

I looked around a bit more about db's and realized that the db scale is not linear, it's actually logrithmic. That means, 70db is actually twice as loud as 60db. That pretty well explains why 70db is way to loud.

This is a great chart... however keep in mind that while sources are MEASURED DIRECTLY, they are evaluated assuming they will be heard FROM A DISTANCE, not directly into the ear. So watch out! I'd imagine the true damage starts at about 70 or 80 when the driver is sitting right in your ear.

Source Measurements
0db - Threashold of human hearing, 1/16 as loud
10db - Music can be interpreted, 1/8 as loud
20db - Bird Songs, 1/4 as loud
30db - Average recording studio, soft music, 1/2 as loud
40db - Arbitrary Base Reference Level
50db - Speech Interfearence, 2x as loud
60db - Intrusive, 4x as loud
70db - Telephone use difficult, 8x as loud
80db - Causes Pain, 16 times as loud
85-90db - Permenant Hearing Damage, 32x as loud
100db - Jet takeoff @ 500m, Diesel truck, jackhammer, 64x
105db - Helicopter, power mower
110db - Typical night club, unsilenced motorcycle @ 7m, 128x
120db - Propeller aircraft, 256x
130db - Military jet, Air raid siren, 512x
110-130db - Rock Concert!, 128-512x
140db - Gun Shot
180db - Rocket Launching

So obviously setting your headphones, which point directly into your ear, at 4x the Base Level, is going to be a bad idea. It looks like 30 to 40db is the most modest starting point, given that's how most music is actually recorded for anyway.

A second point of interest which this chart obscures, is The Equal Loudness Contours. These reveal the average human hearing sensitivity at frequencies in the human hearing range over various listening volumes. It turns out that the human ears are much more sensitive to the high and low frequencies at high volumes than at low volumes. That's why when people go deff from hearing loud noises, they loose the high and low frequencies first. That's a bummer since it's the highs and lows that give music it's punch in the first place. This also explains why music sounds more punchy when its loud, and why recording studios mix the music at low levels.

Lastly, getting back to headphones, I often not when people here review cans they note that they're good but too bright and/or the bass is too much. Perhapse because most of these cans are designed for use in recording studios, where the standard practice is to use them around the Arbitrary Base Reference Level. Right? So if the cans sound to harsh maybe that's because we're all driving them way too loud!!

 

[pedxing]

Thank you very much for clarifying my confusion. Most stupid tables now days leave out the fact that "the measurements are made at the source". Before, I assumed that those readings is what enter my ears.

 

[mshivley]

Thank You every one that responded to my thread....
I realy appreciated all of the information you have shared with
me. Thanks again for taking time to respond.


Mike