Impedance and sound. - AVS Forum
Forum Jump: 
 
Thread Tools
post #1 of 12 Old 07-08-2014, 02:08 PM - Thread Starter
FMW
AVS Special Member
 
FMW's Avatar
 
Join Date: Jun 2007
Posts: 4,773
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 244 Post(s)
Liked: 700
Impedance and sound.

While speaker impedances are within a few ohms of each other, the same is not true of headphones. Headphones vary from impedances similar to those in speakers up into the hundreds of ohms or more.


Since amplifiers are designed with a given output impedance does sound reproduction vary with the input impedance of headphones?
FMW is online now  
Sponsored Links
Advertisement
 
post #2 of 12 Old 07-08-2014, 04:52 PM
AVS Special Member
 
Glimmie's Avatar
 
Join Date: Sep 2000
Location: Los Angeles, CA
Posts: 7,924
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 134 Post(s)
Liked: 213
Quote:
Originally Posted by FMW View Post
While speaker impedances are within a few ohms of each other, the same is not true of headphones. Headphones vary from impedances similar to those in speakers up into the hundreds of ohms or more.


Since amplifiers are designed with a given output impedance does sound reproduction vary with the input impedance of headphones?
It shouldn't with most solid state output stages which have impedaces in the fractions of ohms. Now if you are using a tube headphone amp, then there might be a sonic difference as tube amps have higher output impedance and the loading of the output transformer effects the feedback loop (if one is used).

Glimmie's HT Page
Being redone - comming soon!

Glimmie is offline  
post #3 of 12 Old 07-09-2014, 02:08 AM
AVS Addicted Member
 
arnyk's Avatar
 
Join Date: Oct 2002
Location: Grosse Pointe Woods, MI
Posts: 14,290
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 680 Post(s)
Liked: 1144
Quote:
Originally Posted by FMW View Post
While speaker impedances are within a few ohms of each other, the same is not true of headphones. Headphones vary from impedances similar to those in speakers up into the hundreds of ohms or more.

Since amplifiers are designed with a given output impedance does sound reproduction vary with the input impedance of headphones?
The above is a bit of an over simplification. Amplifiers are designed to drive minimum impedances, and handle higher impedances wonderfully.

The same is true of headphone amps. The ones that drive low impedance headphones well, drive higher impedance headphones well.
arnyk is offline  
post #4 of 12 Old 07-09-2014, 02:49 AM - Thread Starter
FMW
AVS Special Member
 
FMW's Avatar
 
Join Date: Jun 2007
Posts: 4,773
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 244 Post(s)
Liked: 700
Thanks guys. I'm trying to figure out where all the headphone amp sound signature claims come from. I'll assume it is no different than the same claims we hear about amps that drive speakers. I ordered some new headphones for the computer. My plan was and still is to drive them with the receiver that powers my computer speakers. No need for a headphone amp. Take care.
FMW is online now  
post #5 of 12 Old 07-09-2014, 03:27 AM
AVS Addicted Member
 
arnyk's Avatar
 
Join Date: Oct 2002
Location: Grosse Pointe Woods, MI
Posts: 14,290
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 680 Post(s)
Liked: 1144
Quote:
Originally Posted by FMW View Post
Thanks guys. I'm trying to figure out where all the headphone amp sound signature claims come from. I'll assume it is no different than the same claims we hear about amps that drive speakers. I ordered some new headphones for the computer. My plan was and still is to drive them with the receiver that powers my computer speakers. No need for a headphone amp. Take care.
Fact is that while a tiny minority of high end audiophiles use SETs to drive speakers despite their high source impedances, headphone amps that provide a source impedance that is high enough to cause audible coloration are pretty common.

A lot of AVRs drive their headphone jacks with dedicated headphone amps, which can be positive for a nice low source impedance, but there are no guarantees.

When in doubt get a Fiio E5 headphone amp for a < $25 which pretty well guarantees a low source impedance, or measure the impedance of the headphone jack that you have.

Here is a good paper on the topic:

http://test.benchmarkmedia.com/discu...nce-Part-2.pdf
arnyk is offline  
post #6 of 12 Old 07-09-2014, 05:57 AM - Thread Starter
FMW
AVS Special Member
 
FMW's Avatar
 
Join Date: Jun 2007
Posts: 4,773
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 244 Post(s)
Liked: 700
Quote:
Originally Posted by arnyk View Post
Fact is that while a tiny minority of high end audiophiles use SETs to drive speakers despite their high source impedances, headphone amps that provide a source impedance that is high enough to cause audible coloration are pretty common.

A lot of AVRs drive their headphone jacks with dedicated headphone amps, which can be positive for a nice low source impedance, but there are no guarantees.

When in doubt get a Fiio E5 headphone amp for a < $25 which pretty well guarantees a low source impedance, or measure the impedance of the headphone jack that you have.

Here is a good paper on the topic:

http://test.benchmarkmedia.com/discu...nce-Part-2.pdf

I understand. Thanks. I ordered a pair of 600 ohm planar magnetic cans and just wanted to make sure my existing receiver and preamp headphone jacks would handle things properly.
FMW is online now  
post #7 of 12 Old 07-09-2014, 01:16 PM
Member
 
12B4A's Avatar
 
Join Date: Mar 2014
Location: CR Iowa
Posts: 19
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 11 Post(s)
Liked: 11
What are the sensitivity of the headphones? You may run in to a situation where you might not have enough voltage out to provide enough power at that ohm value.
12B4A is offline  
post #8 of 12 Old 07-10-2014, 05:29 AM - Thread Starter
FMW
AVS Special Member
 
FMW's Avatar
 
Join Date: Jun 2007
Posts: 4,773
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 244 Post(s)
Liked: 700
Quote:
Originally Posted by 12B4A View Post
What are the sensitivity of the headphones? You may run in to a situation where you might not have enough voltage out to provide enough power at that ohm value.

That isn't a problem. I think using an Ipod to power them might be a challenge but I'm not worried about a stereo receiver being able to handle the job.
FMW is online now  
post #9 of 12 Old 07-10-2014, 05:34 AM
Member
 
12B4A's Avatar
 
Join Date: Mar 2014
Location: CR Iowa
Posts: 19
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 11 Post(s)
Liked: 11
High probability it will work out. If not, there's always the Hammond 119DA.
12B4A is offline  
post #10 of 12 Old 07-18-2014, 03:05 PM
AVS Addicted Member
 
cel4145's Avatar
 
Join Date: Mar 2009
Location: Grand Rapids, MI
Posts: 11,645
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 212 Post(s)
Liked: 746
Quote:
Originally Posted by FMW View Post
While speaker impedances are within a few ohms of each other, the same is not true of headphones. Headphones vary from impedances similar to those in speakers up into the hundreds of ohms or more.
Although ironically not true for your profile pic--the HE-400:





Attached Images
File Type: png he-400-impedance.PNG (50.0 KB, 30 views)

Your questions are answered: Speaker FAQ
HT: Energy RC-50, RC-LCR, Veritas VS Surrounds | Dual CHT SS 18.1s | Denon AVR-888 | modified Dayton SA1000 | Antimode 8033C
Desktop: CBM-170 SE | SVS SB-1000 | Audio-GD NFB-11 | HK 3390
Headphone & Portable HE-400 | K612 Pro | HP150 | DX50 | E12
cel4145 is offline  
post #11 of 12 Old 07-18-2014, 04:57 PM - Thread Starter
FMW
AVS Special Member
 
FMW's Avatar
 
Join Date: Jun 2007
Posts: 4,773
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 244 Post(s)
Liked: 700
Quote:
Originally Posted by cel4145 View Post
Although ironically not true for your profile pic--the HE-400:





Pretty stable I would say. I didn't mean that the impedance changes a lot with frequency. Obviously it doesn't. I meant that the rated input impedance can cover a wide range. My headphones are rated at 32 ohms although, apparently, your graph shows them at 50 ohms. Some of the popular phones are up in the hundreds of ohms for an input impedance.

The frequency response of the HE-400 certainly doesn't look like that graph. This headphone has a U shaped response curve with a depressed midrange and peaked bass and treble. The sound is calm and luscious. A bit dark with lots of detail in the high treble. You have to spend a whole lot more to do much better than these. These are at a sweet spot in the price/performance curve. Try a pair. They are very nice.

So what is your cat wearing?

Last edited by FMW; 07-18-2014 at 05:00 PM.
FMW is online now  
post #12 of 12 Old 07-18-2014, 05:22 PM
AVS Addicted Member
 
cel4145's Avatar
 
Join Date: Mar 2009
Location: Grand Rapids, MI
Posts: 11,645
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 212 Post(s)
Liked: 746
Quote:
Originally Posted by FMW View Post
Pretty stable I would say. I didn't mean that the impedance changes a lot with frequency. Obviously it doesn't. I meant that the rated input impedance can cover a wide range. My headphones are rated at 32 ohms although, apparently, your graph shows them at 50 ohms. Some of the popular phones are up in the hundreds of ohms for an input impedance.

The frequency response of the HE-400 certainly doesn't look like that graph. This headphone has a U shaped response curve with a depressed midrange and peaked bass and treble. The sound is calm and luscious. A bit dark with lots of detail in the high treble. You have to spend a whole lot more to do much better than these. These are at a sweet spot in the price/performance curve. Try a pair. They are very nice.

So what is your cat wearing?
Sorry. I misunderstood that you meant that headphones have wide impedance variance. And many do. Just not the HiFiMan planar magnetics

Not my cat. That's a Sony April fool's day image: http://mashable.com/2013/04/01/sony-animalia/

Your questions are answered: Speaker FAQ
HT: Energy RC-50, RC-LCR, Veritas VS Surrounds | Dual CHT SS 18.1s | Denon AVR-888 | modified Dayton SA1000 | Antimode 8033C
Desktop: CBM-170 SE | SVS SB-1000 | Audio-GD NFB-11 | HK 3390
Headphone & Portable HE-400 | K612 Pro | HP150 | DX50 | E12
cel4145 is offline  
Reply Audio theory, Setup and Chat

User Tag List

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page


Forum Jump: 

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off