[EliasGwinn]

Quote:

Originally Posted by Punnisher /img/forum/go_quote.gif In my experience, drivers' frequency response is easily changed by adding a resistor adapter. This is especially true with multiple driver iems with crossovers. The amount of change is directly proportional to the resistor value. This change is not a good one, because the earphone loses all of its original characteristics. With dynamic drivers, the change isn't as severe, but still noticeable. I built a board with swappable resistor sockets. I tried resistors from 10 ohms to 150 ohms I believe. In the end, getting an amp with clean sounding output and low gain was my best bet.

Exactly...

Best,
Eilas

 

[nikongod]

All anyone needs to do to disprove that is find a speaker driver that measures more linearly with a high source impedance than a low one.

Enjoy

The key to building an accurate system is to have parts that work well together from end to end. Some speakers simply do work better with a low electrical damping factor.

Also, what is the output impedance of a crossover? Please consider the low pass frequency created by a choke.

 

[Punnisher]

You mean to disprove my post?

For my tomahawk (and portable players with no amp) and all my earphones, this was true. It's very likely that most other earphones will react similarly. Maybe not all though.

 

[marozie]

I could be entirely wrong, but since the gain of the amp is determined via resistors (at least in the Jung Multiloop and the like) what's the difference if that resistance is coming just before the output of the amp or just after it?

 

[nikongod]

Quote:

Originally Posted by Punnisher /img/forum/go_quote.gif You mean to disprove my post?

everyone's really.

Simply stating that higher damping factor is better is clearly not true. It is very easy to find real world situations with off the shelf drivers where it falls apart.

the etymotic ER4 is another fun headphone of this type. The driver is 4.5ohms (or so) with comparably huge resistors to make it a P or an S.

 

[Punnisher]

The only earphone that actually improved with a resistor was the altec lansing uhp330(ue sf3) which is muddy and has no treble extension by default. Adding about 90 ohms evened the sound out entirely, and it had a pleasing and sparkly treble with no more flab in the mids/bass.

This worked out because they sounded horrible out of the box. But if you actually like the sound of your earphones by default, adding a resistor probably won't improve it. Though the end result is entirely subjective I suppose.

 

[poo]

OK, thanks for the healthy discussion guys - very helpful to hear 'both sides'.

So assuming I decide an adaptor plug isn't the way to go, what should I be doing? Is there an alternative inexpensive solution? I don't want to buy an amp (or a new Benchmark DAC for that matter) just to solve the problem.

 

[limpidglitch]

Quote:

Originally Posted by EliasGwinn /img/forum/go_quote.gif Hey there, poo... I highly recommend NOT putting resistors between a set of headphones and any headphone amp. The reason is that it will increase the source impedance, which will diminish the damping ratio - a major factor in the quality of a headphone system. The HPA2 has less then 0.1 ohm output impedance. This optimizes the damping ratio. The proper place in the circuit to attenuate is before the amplifier. Because of user feedback such as yours, we included a 10 dB attenuation option in the DAC1 USB and both a 10 dB and 20 dB attenuation option in the DAC1 PRE and HDR. Best, Elias

Is it possible to 'fake' this extra attenuation by adding resistors to the RCA cables?
In my mind this would be the same as adding a permanent attenuation step on the attenuator, or an extra permanent passive pre-amp, but my mind have led me a stray before…

 

[marozie]

Dude, it's going to cost you all of $5 to make yourself an adapter. If you don't like the way it sounds you haven't really lost anything. And in my opinion there is no appreciable degredation to sound quality as long as you keep your resistor values reasonably low. Christ, some companies give you an adapter with resistors with their IEMs for this very reason. This has turned into an inanely complex argument over a really simple question.

 

[poo]

Marozie, of course "has turned into an inanely complex argument over a really simple question." It's an audio forum!!!

I totally agree with what you're saying in terms of just giving it a go especially given the price to do it! I'm still very open to other suggestions and input, and a potentially better way to do the same thing. The fact I also own a pair of Etymotic ER4p and s make it all the more interesting, given the adaptor/cable they include with resistor is what gave me the idea...

 

[suicidal_orange]

So you already have the resistor cable for the ety's? Try it with the TF10 and decide for yourself if it sounds better/worse/same. Science is great, but it's you who has to listen to it

 

[poo]

^ Not exactly. I have a 'p' cable and an 's' cable which don't fit the custom Shures. Like I said, it's not a problem to make a resistor cable or adaptor, in fact I plan to. I'm more interested in a 'better' or more accurate but similarly cost effective way to do the same thing (as in, not an amp or new DAC/IEMs etc).

 

[marozie]

Quote:

Originally Posted by poo /img/forum/go_quote.gif Marozie, of course "has turned into an inanely complex argument over a really simple question." It's an audio forum!!!

Yes, well, sometimes people get a little carried away following the rabbit hole. It's one thing if you're going to build and amp or do something of similar investment and want to make sure you get it right. It's another thing to throw together $5 of parts with 15 minutes of your time and see what the result is. In my opinion it will achieve exactly what you're trying to do, but maybe your ears will disagree. The point is, it's so simple to derive empirically that it's almost not worth the thought experiment.

 

[EliasGwinn]

Marozie…good point, very true...it is certainly worth empirical experimentation.

I apologize if I mis-directed the conversation. I simply wanted to explain the science behind this type of configuration.

Nikongod, thanks for that link…it is an interesting read. I haven’t finished it yet, but from what I have read so far, he is commenting on the subjective quality of the sounds from his experiments…true to ‘Pass’ style. I would never question someone’s subjective preferences, as I mentioned before. But I’d like to finish the article before I make any more comments on it…

Poo, are you using the Airport Express to drive the DAC1? If so, just attenuate the volume in iTunes. The digital volume control in iTunes performs very well, and, although digital volume control will reduce dynamic range, I think it is the least-problematic (and cheapest) way to solve your problem.

Limpidglitch, are you referring to the RCA inputs or outputs? Either way, a set of precision matched passive attenuators on analog RCA cables would work. However, there are no analog RCA inputs on the classic DAC1, and Poo is using the headphone outputs, so this won’t work for Poo.

Best,
Elias

 

[limpidglitch]

Quote:

Originally Posted by EliasGwinn /img/forum/go_quote.gif Limpidglitch, are you referring to the RCA inputs or outputs? Either way, a set of precision matched passive attenuators on analog RCA cables would work. However, there are no analog RCA inputs on the classic DAC1, and Poo is using the headphone outputs, so this won’t work for Poo. Best, Elias

Yes, I thought he used a seperate amplifier and that he could attenuate between the two components, so no go there.