Just listened to some Fostex T50RPs today... WOW!

[RexAeterna]

i was gonna use polyfill instead but i have none left. it should work as well as acoustic foam in headphone enclosure. if not i would assume fiberglass will work as well. just happy i finally eliminated the annoying midrange resonance and wanted more clarity from them. cotton is only thing i have currently so that's what i used. won't be able to get anything else till the weekend. i heard blue-tuck stuff is good. combine that with some polyfill/fiber fill and should be perfect i'm guessing. i'm just so puzzled why fostex did this. they're leader still in planer designs and know main flaw with planer drivers is resonance. the plastic cup has nothing in it. no wonder it suffered and the drivers touched my ears cause original pads are very thin and not very good. reason why i'm using pair of extra leather 240 sextett pads instead. way much better seal.

 

[mrspeakers]

Quote:

i was gonna use polyfill instead but i have none left. it should work as well as acoustic foam in headphone enclosure. if not i would assume fiberglass will work as well. just happy i finally eliminated the annoying midrange resonance and wanted more clarity from them. cotton is only thing i have currently so that's what i used. won't be able to get anything else till the weekend. i heard blue-tuck stuff is good. combine that with some polyfill/fiber fill and should be perfect i'm guessing. i'm just so puzzled why fostex did this. they're leader still in planer designs and know main flaw with planer drivers is resonance. the plastic cup has nothing in it. no wonder it suffered and the drivers touched my ears cause original pads are very thin and not very good. reason why i'm using pair of extra leather 240 sextett pads instead. way much better seal.

No, polyfill serves a totally different purpose.  It is a replacement for cotton, actually.  Cottton and poly can do a bit to reduce standing wave modes, but acoustic foam actually absorbs sound at certain frequencies.  
 

 

[RexAeterna]

so fiberglass will most likely work better or mineral wool? i know they can be get locally cheap. do local stores sell that blu-tack(i think i spelled it right) locally as well? i know fiber glass and mineral wool can absorb frequencies down to 20hz and midrange and high frequencies are easier to absorb and slow down due to their wave length and speed so materials of less than fiber glass or mineral wool can do some good. i'm thinking of fiberglass and mineral wool instead cause it's as effective as acoustic foam but much cheaper comes in larger quantity most likely.

 

[kingoftown1]

Just got my O2 in, and with the additional power the bass is maybe just a tad overwhelming.  Seems like a good excuse to open up the Fostex again and try playing with cotton/vent tuning.

 

[RexAeterna]

Just got my O2 in, and with the additional power the bass is maybe just a tad overwhelming.  Seems like a good excuse to open up the Fostex again and try playing with cotton/vent tuning.

they do seem to like power. i have them running off of speaker outputs like i always do with headphones and have great results with them. tried them off of headphone jacks and they were pain to drive despite their 98db claim. they do need some good amount of current going through especially for sub-bass and bass frequencies. i have nice bass response close to my pioneer monitor 10's when i had them. nice tight bass and well dampen bass. but feed them power and sub-bass can become much more greater.

wonder if i'm te only one around here uses beefy power amps instead to drive headphones off of speaker outputs cause it seems like it. you guys should try it sometime. it does wonders and not just for planers and electrostatics. don't have to worry about electrical dampening either if using solid state cause output impedance is always close to 0,always on the speaker outputs by design.

 

[randomZash]

Quote:

yes. accurate headphone will not sound same level of volume across the frequency spectrum cause the human ear is less sensitive to some frequencies compared to others. that's why i don't understand people try to argue with me saying in order to have a balanced sound(what i take meaning flat and accurate with no accentuation of any part of frequency) is the frequencies from 20hz-20khz all have to have the same volume level. it doesn't work that way. if headphone was ruler flat it still will not sound the same due to human hearing roll-offs and cut-outs and will be God awful bright and ear piercing if the treble and air frequencies are flat cause how close the drivers are and if you still have your hearing intact in the high frequencies.
speakers,amps,dacs and rooms are meant to be ruler flat. not headphones.

I found a very useful and interesting page by Tyll from innerfidelity.com this makes a lot more sense now.
 
"The head is designed to act exactly like the average human listening system. Inside the head at very much the same position of your eardrums at the end of your ear canal, are two very special microphones (one in each ear) that mimic the exact acoustic impedance characteristics of your eardrum. The shape of the ears is also very precisely defined (IEC specification 60268-7) so as to act just like the average human ear. The goal of this device is to provide a measurement of exactly what is heard at the eardrum for sound arriving at the head. Because headphones are coupled directly to the head, it is only by using a device such as this that headphone measurements can be made that relate strongly to what we hear. "
 
check it out, http://www.innerfidelity.com/content/headphone-measurment-proceedures-introduction-and-equipment

 

[RexAeterna]

I found a very useful and interesting page by Tyll from innerfidelity.com this makes a lot more sense now.

"The head is designed to act exactly like the average human listening system. Inside the head at very much the same position of your eardrums at the end of your ear canal, are two very special microphones (one in each ear) that mimic the exact acoustic impedance characteristics of your eardrum. The shape of the ears is also very precisely defined (IEC specification 60268-7) so as to act just like the average human ear. The goal of this device is to provide a measurement of exactly what is heard at the eardrum for sound arriving at the head. Because headphones are coupled directly to the head, it is only by using a device such as this that headphone measurements can be made that relate strongly to what we hear. "

check it out, http://www.innerfidelity.com/content/headphone-measurment-proceedures-introduction-and-equipment

yea,he uses a little anechoic chamber for measuring the headphones on the headphone dummy. lot of headphones are measured in an anechoic chamber. some are measured diffused-field but very rarely. only sennheiser top models and supposedly AKG from what they told me when i asked bout getting documentation,graphs and info of my 240DF's told me 271 and 702 are still diffused-field equalized. electrostatics are mostly free-field equalized in an anechoic chamber. only few dynamics were free-field equalized. i don't know about planers. yamaha or fostex never gave info on what type of chamber or type of measuring they used for their headphones.

 

[drez]

Have finished my rewire with DHC Nucleotide wire, also:
 
-plastaciene loaded baffle
-2.5mm stiff felt to back of driver
-1.5mm soft felt to back of cup
-earcup side felt removed
-bass ports closed
 
Sounds promicing but the midrange is still quite peaky.  Needs more damping inside cup?

 

[fishski13]

Quote:

they do seem to like power. i have them running off of speaker outputs like i always do with headphones and have great results with them. tried them off of headphone jacks and they were pain to drive despite their 98db claim. they do need some good amount of current going through especially for sub-bass and bass frequencies. i have nice bass response close to my pioneer monitor 10's when i had them. nice tight bass and well dampen bass. but feed them power and sub-bass can become much more greater.
wonder if i'm te only one around here uses beefy power amps instead to drive headphones off of speaker outputs cause it seems like it. you guys should try it sometime. it does wonders and not just for planers and electrostatics. don't have to worry about electrical dampening either if using solid state cause output impedance is always close to 0,always on the speaker outputs by design.

my DIY Pass F5 can pump 25W but is a low gain amp at 15dB.  fronted by a unity gain buffer for preamp, i can easily hit 12 o'clock driving my K702 - the F5 is way over-kill in power but i like the sonics.  as long as DC offset is low on speaker taps and you don't have too much gain for volume control, using a speaker amp is fine.  i'm planning on a re-wire for my T50RP and will build an adapter for the F5 speaker taps.   

 

[RexAeterna]

once you dampen the cups the highs comes out of hiding even more with far more extension and the stereo imaging increase big time as well when you bring the highs out due to treble brings bigger dispersion pattern(mainly reason why tweeters are also responsible for soundstage and imaging as well). these things have ridiculous amounts of details. i really like the highs on these,don't know why i heard complaints about the highs of planer magnetic drivers before cause these are some of the best highs i heard so far. gonna compare them later to my sextetts lp and 240DF's. so far i can tell after dampening the cups the clarity in the midrange is better than my sextetts just from memory. actually glad now i didn't decide to buy that extra 240DF from a local(was gonna get it as a back-up cause i already have one and casue 240DF's are still my favorite headphone ever) and tried these out. didn't know there was this much potential in these headphones and people were full of it to be honest.

 

[rhythmdevils]

damping is more important to orthos than improvements in amplification IME.  I would take a well damped ortho out of an ipod or portable amp over an improperly damped ortho out of a Liquid Fire/Balancing Act/Apex Pinnacle etc with similar quality source. 

 

[RexAeterna]

my DIY Pass F5 can pump 25W but is a low gain amp at 15dB.  fronted by a unity gain buffer for preamp, i can easily hit 12 o'clock driving my K702 - the F5 is way over-kill in power but i like the sonics.  as long as DC offset is low on speaker taps and you don't have too much gain for volume control, using a speaker amp is fine.  i'm planning on a re-wire for my T50RP and will build an adapter for the F5 speaker taps.   

i heard lot about the f5 amp since the k1000 was popular. looks like a great class A amp for strictly headphone use and high sensitivity speakers. i use amps at least with 40wpc( real watts where the watt is measured correctly from 20hz-20khz, not how modern amps are only measured at 1khz). i tried bigger class A amps with headphones as well but no point unless it uses a -20db muting switch cause damn you'll have ridiculous amount of headroom with that and better off using very high impedance and very low sensitive headphones to be usable. i say any good built low-powered speaker amp be wonderful alternative for headphone driving. i use to know lot of people back in the 70's for studios use to use DIY boxes to hook headphones off of speaker outputs to power them(another reason why lot of studio headphones back then were wired with 4-core balanced TRS/DIN jacks,so they could be stripped and used directly off of speaker outputs if needed.)

 

[RexAeterna]

damping is more important to orthos than improvements in amplification IME.  I would take a well damped ortho out of an ipod or portable amp over an improperly damped ortho out of a Liquid Fire/Balancing Act/Apex Pinnacle etc with similar quality source. 

i noticed that. always knew about planer drivers for speakers but never really bothered with headphones,but i did get an opportunity before to audition a pair of yamaha HP-1 for about month and enjoyed it. been reading up on them and so far they seem very identical to ribbons. seems more important for mechanical dampening for ortho then electrical cause i tested these off of random headphone jacks across the house and had good results as well but some amps i had to hit pass 1 o'clock to get any volume despite their 98db claim.

 

[gurubhai]

^The Yamaha HP-1 is 94 dB/mW, not 98 dB/mW. There is a higher efficiency version with so-called anisotropic magnets but even that one is 96dB/mW.

 

[RexAeterna]

^The Yamaha HP-1 is 94 dB/mW, not 98 dB/mW. There is a higher efficiency version with so-called anisotropic magnets but even that one is 96dB/mW.

i know. i was mentioning my fostex when i tested around my house. should of been more clearer on that part. it's my fault. sorry about that.