Exactly what is a level attenuator, what does it do & how can it help an ipod?

[omendelovitz]

As my title says, I don't know what to do witht this little attenuator doo-dad. Someone suggested plugging in my headphones into it and then into pocket-dock out of my iPod's line-out to get some seriously good sound. Any truth or accuracy to this? what about volume adjustment? won't that be affected?

Thanks in advance!

Oriel

 

[joelongwood]

Attenuaters are usually nothing more than resistors placed in the signal path. You will have to turn up the volume more to acheive your desired volume. As for improving the sound, that really depends on the headphones. Some benefit (to some ears) is acheived when headphones such as the ER4P, have 75 ohm resistors placed in the path,and become ER4S.......smoother sound with no graininess.
My Beyer DT-831 benefits greatly from a 120 ohm adapter, as it tames the brightness and brings the bass up, thus providing a more balanced sound.
In a nutshell, you have to try it to see if it improves the sound (for you), as I've found it to be kind of a hit or miss affair. Hope this helps.

 

[omendelovitz]

Ah Joe, just the man I was looking to hear from. It sounds to me like the attenuator placed into the headphone jack of my iPod may also help w/the sub-100Hz rolloff issue, wouldn't it? That would be a great boost for both the e4's and my Grado's! Can you confirm/deny my assumptions?

Thanks in advance.

O

 

[kramer5150]

Its a variable resistor you plug between your phones and amp/player.
They sell a version at radio shack for ~$6

Ive never encountered a situation where it'll boost bass. on my KSC75 it does the opposite, reduces the bass (and midrange) hump. ony me e2c it presents a higher impedenceload to the amp to reduce amp hiss, but does not alter the sonic signature.

IMHO for $6 its wrth a try but I doubt it will result in boosted bass.

Garrett

 

[joelongwood]

Quote:

Originally Posted by omendelovitz Ah Joe, just the man I was looking to hear from. It sounds to me like the attenuator placed into the headphone jack of my iPod may also help w/the sub-100Hz rolloff issue, wouldn't it? That would be a great boost for both the e4's and my Grado's! Can you confirm/deny my assumptions? Thanks in advance. O

I'm not sure if you're talking about an attenuater such as the RS one that Garrett referred to, or to something else.
In any case, I don't think it works for your intended purpose, as I just tried the RS adapter with Grados......and as Garrett reported, no difference that I can detect. Then I plugged in the 120 ohm adapter, and while it may have resulted in a bit more bass, to my ears, it caused a loss of detail (a major reason for owning Grados), the volume at full was barely loud enough.
If you have the ERP, a 75 ohm adapter will convert it to a 4S, which has a smoother overall response, but not noticeably more bass. Again, the volume control will have to be increased more and you may find not enough range is available when you want to listen occassionally at louder than normal volumes. If you have a 4S, I think you may run into the issue of whether there is enough volume.
It's kinda strange, and I don't understand it, why certain headphones such as the ER6i are designed specifically for iPods, when recent postings suggest that the iPod has a bass roll-off with low impedance 'phones. Yet, the iPod doesn't seem to have enough juice to run high impedance 'phones effectively.

Save the $6 or so and put it toward an amp.....the Pocketampv2 at around $60, is IMHO, a rather cost effective way to give a little boost to the lower frequencies. While it doesn't have a bass boost per se, it seems to emphasize the low end a bit.......and tighten up what is already there.
Hope this helps.

 

[Snowmac]

The level attenuator on my Shure E4Cs is meant for use with high powered sources such as airplane sound systems where the volume would be too loud for the earphones. I don't think you will get any benefit from using them on an iPod.

 

[omendelovitz]

Thanks for the feedback, all. After reading separate posts about the iPod and it's bass issues w/ low resistance headphones (grados and most earbuds/canalphones), I figured that added resistance (such as a level attenuator) bringing the ohmage to 75+ would help with the bass rolloff issues. That's mainly why I asked. Considering the bass increase I get when using my 60 Hz Koss PP's, I figured that maybe I could use a level attenuator to mimic the increased resistance of a higher resistance phone like my Koss phones. BTW, anybody try running the attenuator through an iPod line out via a pocket dock or siK line out adapter? What were the results? just curious.

Cheers!

Oriel

 

[jeffc]

Quote:

Originally Posted by omendelovitz Thanks for the feedback, all. After reading separate posts about the iPod and it's bass issues w/ low resistance headphones (grados and most earbuds/canalphones), I figured that added resistance (such as a level attenuator) bringing the ohmage to 75+ would help with the bass rolloff issues. That's mainly why I asked. Considering the bass increase I get when using my 60 Hz Koss PP's, I figured that maybe I could use a level attenuator to mimic the increased resistance of a higher resistance phone like my Koss phones. BTW, anybody try running the attenuator through an iPod line out via a pocket dock or siK line out adapter? What were the results? just curious. Cheers! Oriel

Most of the Harddrive-based iPods use a Wolfson Microelectronics Codec. The iPod probably uses recommended the headphone output circuit listed on page 37, which adds capacitors that AC-couple the headphones to the output stage. The effect of AC-coupling is to put a high-pass filter whose corner frequency is related to the impedance of the headphones (with a 16 ohm headphone, the corner frequency is 45hz). So yes, an attenuator like the ER4P-to-ER5S cable improve the bass response of the iPod. The cost of adding the attenuator is to consume power, thereby shortening the time between recharging the battery.

You probably don't want to connect your headphones to the line-out. The recommended circuit assumes that the line-out load will be high-impedance: with a 100 ohm headphone, the corner frequency will be about 800ohms. Most of the musical content is below this frequency.

 

[bangraman]

Attaching an attenuator to the headphone out would get rid of the bass falloff issue. There's a noticeable amount of recovered bass with low-impedance phones such as the E2c, ER-6i and the EX71 when you significantly raise the effective impedance on them. The only issue would be the cheap-ass rotary pot in the attenuator, the primary issue of which would be channel imbalance. The 4P-S adaptor, or even better something like that built by Fidaudio, JMTAudio, Moon Audio, etc would probably do a better job.


Generally speaking though, I'd leave it be or buy higher-impedance phones.

 

[omendelovitz]

Quote:

Originally Posted by bangraman Attaching an attenuator to the headphone out would get rid of the bass falloff issue. There's a noticeable amount of recovered bass with low-impedance phones such as the E2c, ER-6i and the EX71. The only issue would be the cheap-ass rotary pot in the attenuator, the primary issue of which would be channel imbalance.

Hey Bangraman,

Do you think the attenuator off of the Shure E4's would be a decent one, or would it be a cheapie pot? I know another person above posted the $6 attenuator solution, but I'm expecting to get the E4's soon and they are supposed to come w/ a shure attenuator from which I would've expected good quality...

Thanks.

O

 

[bangraman]

I do believe the Shure attenuator sells for $8... so I couldn't say what level of improvement there would be.

 

[ski91902]

would using the attenuator and setting it to a certain level be the same as using a etymotic 4p-s wire? It sure would be a lot cheaper

 

[bangraman]

As I mentioned, the basic effect of getting around the bass falloff would be the same but you have the issues of a cheap rotary potentiometer to deal with. Channel imbalance which may bother you to varying degrees, channel crosstalk effects, sound quality degredation and other nasties await. Of course, it doesn't hurt to try it.


Incidentally the typical selling price of the Ety cable is ridiculous. You could make your own for much less, even if you invested in higher-priced cable and bought a bunch of resistors to hand-match. I wonder why it's so expensive nowadays?

 

[bangraman]

This is just gone up at my blog. It might be of interest... or not.

http://phonephile.blogspot.com/2005/...-fall-off.html

 

[titaniumx3]

Quote:

Originally Posted by bangraman This is just gone up at my blog. It might be of interest... or not. http://phonephile.blogspot.com/2005/...-fall-off.html

That was excellent, some of the most reasonable comments about the ipod I have ever heard.