CHANGSTAR: Audiophile Headphone Reviews and Early 90s Style BBS

Lobby => Headphone Measurements => Topic started by: Marvey on April 09, 2012, 01:39:45 AM

Title: Koda T50RP Frequency Response and CSD Waterfall Plots
Post by: Marvey on April 09, 2012, 01:39:45 AM
Koda T50RP Frequency Response

(http://www.changstar.com/index.php?action=dlattach;topic=208.0;attach=828;image)

They sound exactly like the graph above. First three notes on a Natalie Merchant track, and I already started to Wonder.
Title: Re: Koda T50RP Frequency Response and CSD Waterfall Plots
Post by: rhythmdevils on April 09, 2012, 01:52:37 AM
I wonder if he removed the stock driver damping paper and left the driver open on the back.  Looks like uncontrolled resonant, undamped bass to me! 

Interesting to see how clean the CSD is in the upper mids regardless.  Go fostex! 
Title: Re: Koda T50RP Frequency Response and CSD Waterfall Plots
Post by: RexAeterna on April 09, 2012, 02:25:20 AM
he seriously didn't hear that? what a shame. he put so much effort in the external design and it did look very pretty. he seemed to quit though. i guess he gotten discouraged after this. shouldn't of though and could of fixed things with it, or had someone else do the sound/acoustic work for him. the design had lot of potential itself but i guess what can you do, ya know. stuff happens.
Title: Re: Koda T50RP Frequency Response and CSD Waterfall Plots
Post by: Anaxilus. on April 09, 2012, 04:11:23 AM
Woah!  He could have won a 701 from Tyll.
Title: Re: Koda T50RP Frequency Response and CSD Waterfall Plots
Post by: RexAeterna on April 09, 2012, 06:56:33 AM
man if i knew there was a free q701 for worst sounding headphones i should of entered mine in to win first prize! i could of been rocking Quincy G right now and everyone be

person 1: ''yo,dog. yo, dog! u see dis fool?''

person 2: ''ya, i see dis fool. so what?''

person 1: '' dat crazy mofo is rocking some quincy's dog''

*stares at each for quick second and looks back* and says

person 1 and 2: he's sooo hood!

yeaaa, i be scoring hood rats in no time.

Title: Re: Koda T50RP Frequency Response and CSD Waterfall Plots
Post by: maverickronin on April 09, 2012, 08:41:30 PM
His driver damping on that version was felt with hole cut out over the middle the middle square of the driver.
Title: Re: Koda T50RP Frequency Response and CSD Waterfall Plots
Post by: cn11 on April 10, 2012, 05:52:06 PM
And the graphs can't convey how constricted the soundstage was, or the weird tonality to how voice and midrange instruments sounded. Definitely too bad they sound like that, because the workmanship is beautiful.
Title: Re: Koda T50RP Frequency Response and CSD Waterfall Plots
Post by: LFF on April 10, 2012, 06:06:48 PM
To me, the KODA^2 was a reference level can. It's truly a reference for how bad a headphone can sound. I can honestly say it is the worst sounding headphone I have ever heard.

I know, however, that others disagree. (http://www.youtube.com/watch?v=uZJnvVKgHig)
Title: Re: Koda T50RP Frequency Response and CSD Waterfall Plots
Post by: rhythmdevils on April 10, 2012, 06:42:32 PM
As I was trying to tell people in the T50rp thread, the cabling and enclosure is decidedly not what is holding these cans back.  ;)
Title: Re: Koda T50RP Frequency Response and CSD Waterfall Plots
Post by: LFF on April 10, 2012, 07:14:35 PM
As I was trying to tell people in the T50rp thread, the cabling and enclosure is decidedly not what is holding these cans back.  ;)

I agree. If there is a limiting factor IMHO, it's the size of the driver. I wish I had a big beefy one to play with!
Title: Re: Koda T50RP Frequency Response and CSD Waterfall Plots
Post by: rhythmdevils on April 10, 2012, 07:34:41 PM
Hey, I offered to send you the NAD RP18's to play with.  Working on them is a bit different though since they are open back. 

I personally think a driver slightly bigger than the T50rp, but smaller than the LCD-2 would be pretty great.  Maybe 1.5x the size of the T50rp driver.  You'd get better bass quality and detail retrieval and maybe better HF extension, but it would still keep the cost and weight down. 
Title: Re: Koda T50RP Frequency Response and CSD Waterfall Plots
Post by: LFF on April 10, 2012, 07:45:14 PM
Hey, I offered to send you the NAD RP18's to play with.  Working on them is a bit different though since they are open back. 

I personally think a driver slightly bigger than the T50rp, but smaller than the LCD-2 would be pretty great.  Maybe 1.5x the size of the T50rp driver.  You'd get better bass quality and detail retrieval and maybe better HF extension, but it would still keep the cost and weight down.

I agree.

Did I give you a reason as to why I declined the RP18's?
Title: Re: Koda T50RP Frequency Response and CSD Waterfall Plots
Post by: rhythmdevils on April 10, 2012, 08:00:12 PM
Yeah, no worries I didn't mention it like that, may have come off the wrong way.  Same reason I haven't gotten to them- not enough time!  It takes so long, and I'm happy with the orthos I've got tuned now.  I may try some new tricks though when they come back....
Title: Re: Koda T50RP Frequency Response and CSD Waterfall Plots
Post by: LFF on April 10, 2012, 08:04:00 PM
Yeah, no worries I didn't mention it like that, may have come off the wrong way.  Same reason I haven't gotten to them- not enough time!  It takes so long, and I'm happy with the orthos I've got tuned now.  I may try some new tricks though when they come back....

The reason I ask is because I have had a few people offer other orthos up to mod but 1) I don't want to ruin a perfectly working pair (especially if its a vintage unit) and 2) I don't have the means to manufacture new housing if I need it. However, the biggest reason is no.1.
Title: Re: Koda T50RP Frequency Response and CSD Waterfall Plots
Post by: RexAeterna on April 10, 2012, 08:50:33 PM
To me, the KODA^2 was a reference level can. It's truly a reference for how bad a headphone can sound. I can honestly say it is the worst sounding headphone I have ever heard.

I know, however, that others disagree. (http://www.youtube.com/watch?v=uZJnvVKgHig)

well with this there is one point that is proven. looks do matter and makes a difference!
Title: Re: Koda T50RP Frequency Response and CSD Waterfall Plots
Post by: omegakitty on April 11, 2012, 02:14:00 AM
Hey, I offered to send you the NAD RP18's to play with.  Working on them is a bit different though since they are open back. 

I personally think a driver slightly bigger than the T50rp, but smaller than the LCD-2 would be pretty great.  Maybe 1.5x the size of the T50rp driver.  You'd get better bass quality and detail retrieval and maybe better HF extension, but it would still keep the cost and weight down.

If you get around to the RP18 I am very interested in seeing what can be done. I had a pair with some dampening done (maybe only 1 or 2 layers of 1 mm felt) and they had nothing over 6 KHz. And I do not mean this in a normal headphone hyperbolic way. They literally had 0 frequencies past that. I think the pair I sold went through 3 owners in a months period before ending up in cetoole's headphone void (and I believe someone has them on loan, or maybe not, been a while since I asked him).
Title: Re: Koda T50RP Frequency Response and CSD Waterfall Plots
Post by: rhythmdevils on April 11, 2012, 02:25:07 AM
I've worked on them a fair amount already, but they are currently with dBel84 for wiring repairs.  I have both the mylar and kapton versions and both are capable of treble on par (or better, it's been awhile) than the LCD-2 depending on the damping.  I haven't gotten the upper midrange to my liking so far.  But I'm a picky bastard in that way.  They definitely extend past 6khz that's for sure.  Sounds like your pair may have fallen out of grace with the ortho Gods. 

For a look at what they are capable of measurement wise, check out Kabeer's modded Aiwa HP500 which won 1st place in Innerfidelitiy's DIY contest.  It's a variant of the same driver. 
Title: Re: Koda T50RP Frequency Response and CSD Waterfall Plots
Post by: omegakitty on April 11, 2012, 02:27:01 AM
I've worked on them a fair amount already, but they are currently with dBel84 for wiring repairs.  I have both the mylar and kapton versions and both are capable of treble on par (or better, it's been awhile) than the LCD-2 depending on the damping.  I haven't gotten the upper midrange to my liking so far.  But I'm a picky bastard in that way...

For a look at what they are capable of measurement wise, check out Kabeer's modded Aiwa HP500 which won 1st place in Innerfidelitiy's DIY contest.  It's a variant of the same driver.

Ok so there are two distinct versions of the RP18 then?

And am I correct in thinking it is a rebadged T50v2 and not a T50v1? It has been so long since I owned them/ortho modded.

edit: yeah I am wondering if my pair were broken. My memory isn't quite so good on these, but I thought someone else around the time said they weren't able to do much with an RP18. I'll see if cetoole was able to get anything more out of them. I think the last time we talked he said he was able to eek more mids and treble out of them, but still very very dark.
Title: Re: Koda T50RP Frequency Response and CSD Waterfall Plots
Post by: rhythmdevils on April 11, 2012, 02:33:39 AM
Actually it looks like it's based on the T50v0 and yeah there are 2 versions.  One has a mylar diaphragm, which is closer to the T50 sound, and is pretty decent stock.  The other has a kapton diaphragm and has the craziest bass you'll ever hear in a headphone.  Like Beats and Audeze had a baby.  Of course the goal is to bring it in check with the right mods.  I had more luck on the mylar version because it requires less damping.  It would be fun to mod the kapton for extreme bass and send it to Tyll with a b logo wrapped around the headband :-)

The Wikiphonia page has some good info.  (http://wiki.faust3d.com/wiki/index.php?title=Fostex_T50)
Title: Re: Koda T50RP Frequency Response and CSD Waterfall Plots
Post by: omegakitty on April 11, 2012, 03:13:09 AM
Yup mine definitely had that uber thumping bass sound. I'd love to see the FR/CSD of those stock  :'(
Title: Re: Koda T50RP Frequency Response and CSD Waterfall Plots
Post by: LFF on April 11, 2012, 04:27:18 AM
Yup mine definitely had that uber thumping bass sound. I'd love to see the FR/CSD of those stock  :'(

Stock T50RP:
http://www.changstar.com/index.php/topic,62.0.html

http://www.changstar.com/index.php/topic,62.0.html
Title: Re: Koda T50RP Frequency Response and CSD Waterfall Plots
Post by: gurubhai on April 11, 2012, 07:19:59 AM
^I think omegakitty meant for measurements of original 1975 Fostex T50, not the current T50RP.
Title: Re: Koda T50RP Frequency Response and CSD Waterfall Plots
Post by: omegakitty on April 11, 2012, 02:10:52 PM
^I think omegakitty meant for measurements of original 1975 Fostex T50, not the current T50RP.

Correct I'd be very interested in seeing the undampened RP18 (Fostex T50v2 or v0? just for lols) as well as a dampened T50v1, which I know a buddy has and uses a lot even amidst his nice collection.
Title: Re: Koda T50RP Frequency Response and CSD Waterfall Plots
Post by: gurubhai on April 11, 2012, 02:42:53 PM
I have had the chance to hear two NAD RP18s (both mylar) & I would expect them to measure very well  stock compared even to current High-end headphones.
The stock mylar NAD are pretty neutral sounding with slight roll-off at either end of spectrum. Apart from a peak at around 4k, they are pretty clean & smooth sounding. The damping is nearly perfect stock.
The one area where it lags behind the current offerings is the soundstage, its pretty limited.
Title: Re: Koda T50RP Frequency Response and CSD Waterfall Plots
Post by: LFF on April 11, 2012, 03:19:44 PM
Anybody have a spare set of RP18's they want to sell?
Title: Re: Koda T50RP Frequency Response and CSD Waterfall Plots
Post by: omegakitty on April 11, 2012, 03:31:32 PM
Anybody have a spare set of RP18's they want to sell?

Get in touch with cetoole. He might still have his.

edit: LFF I'll just ask him tonight :)
Title: Re: Koda T50RP Frequency Response and CSD Waterfall Plots
Post by: LFF on April 11, 2012, 04:01:01 PM
Anybody have a spare set of RP18's they want to sell?

Get in touch with cetoole. He might still have his.

edit: LFF I'll just ask him tonight :)

Thanks! I sent him a message.
Title: Re: Koda T50RP Frequency Response and CSD Waterfall Plots
Post by: rhythmdevils on April 11, 2012, 06:03:06 PM
I'm not sure I'd recommend that one if it doesn't extend past 6khz.  A lot can happen to a pair of headphones in 30 years... If you're going after one, I think you would like the Mylar version best.  They seem to pop up much more often in Germany if you have a friend over there.  That's how I got mine.

I have had the chance to hear two NAD RP18s (both mylar) & I would expect them to measure very well  stock compared even to current High-end headphones.
The stock mylar NAD are pretty neutral sounding with slight roll-off at either end of spectrum. Apart from a peak at around 4k, they are pretty clean & smooth sounding. The damping is nearly perfect stock.
The one area where it lags behind the current offerings is the soundstage, its pretty limited.

What pads?  I had some very deep pads on mine and they had excellent soundstage.  W11 pads also seem to give them good soundstage, though it's more up and down than left to right. 

Maybe we should have an ortho forum here.   8)
Title: Re: Koda T50RP Frequency Response and CSD Waterfall Plots
Post by: LFF on April 11, 2012, 06:09:13 PM
I'm not sure I'd recommend that one if it doesn't extend past 6khz.  A lot can happen to a pair of headphones in 30 years... If you're going after one, I think you would like the Mylar version best.  They seem to pop up much more often in Germany if you have a friend over there.  That's how I got mine.

I have had the chance to hear two NAD RP18s (both mylar) & I would expect them to measure very well  stock compared even to current High-end headphones.
The stock mylar NAD are pretty neutral sounding with slight roll-off at either end of spectrum. Apart from a peak at around 4k, they are pretty clean & smooth sounding. The damping is nearly perfect stock.
The one area where it lags behind the current offerings is the soundstage, its pretty limited.

What pads?  I had some very deep pads on mine and they had excellent soundstage.  W11 pads also seem to give them good soundstage, though it's more up and down than left to right. 

Maybe we should have an ortho forum here.   8)

Nein. I have no friends in Germany.... :'(
Title: Re: Koda T50RP Frequency Response and CSD Waterfall Plots
Post by: Marvey on April 11, 2012, 06:39:41 PM
Maybe we should have an ortho forum here.   8)


Created one in the Main Deck (to keep it from turning into something like HF.)
Title: Re: Koda T50RP Frequency Response and CSD Waterfall Plots
Post by: gurubhai on April 11, 2012, 07:23:43 PM
forum fart
Title: Re: Koda T50RP Frequency Response and CSD Waterfall Plots
Post by: omegakitty on April 11, 2012, 07:43:03 PM
I'm not sure I'd recommend that one if it doesn't extend past 6khz.  A lot can happen to a pair of headphones in 30 years... If you're going after one, I think you would like the Mylar version best.  They seem to pop up much more often in Germany if you have a friend over there.  That's how I got mine.

I have had the chance to hear two NAD RP18s (both mylar) & I would expect them to measure very well  stock compared even to current High-end headphones.
The stock mylar NAD are pretty neutral sounding with slight roll-off at either end of spectrum. Apart from a peak at around 4k, they are pretty clean & smooth sounding. The damping is nearly perfect stock.
The one area where it lags behind the current offerings is the soundstage, its pretty limited.

What pads?  I had some very deep pads on mine and they had excellent soundstage.  W11 pads also seem to give them good soundstage, though it's more up and down than left to right. 

Maybe we should have an ortho forum here.   8)

Maybe we should have an ortho forum here.   8)


Created one in the Main Deck (to keep it from turning into something like HF.)

That's funny  :P I defected from an ortho ninja to stax mafia 4 or 5 years ago, though this forum has me more interested in investigating tube amps for vintage orthos. I had a 7788 spud amp with Electraprint OPTs that sounded really good with the LCD-2r1.
Title: Re: Koda T50RP Frequency Response and CSD Waterfall Plots
Post by: rhythmdevils on April 11, 2012, 09:06:58 PM
Woops, sorry about that Guru.  :-/ 

Yeah, stock they are horrendous, basically have no pads at all.  Made for aliens with square heads and seal ears.  I think pads may be the biggest factor for soundstage with an ortho since they can't be as open as dynamics. 
Title: Re: Koda T50RP Frequency Response and CSD Waterfall Plots
Post by: devouringone3 on November 18, 2012, 08:49:47 AM
Though I heard multiple times that the stock T50RP pads are not the best sounding ones, and that I do find they irritate your ears to the point of becoming atrociously painful and unwearable, when you stuff a KSC75 pad (or an equivalent like a Radio Shack's; I use Sennheiser PX100's) in the oval where goes your ear, the foam and the pleather will combine and make up for an all around excellent comfort (and soothe your aching ears).



I still am optimist that I'll be able to open, mod and improve my Koda^2 headphones to decent sounding state.
Title: Re: Koda T50RP Frequency Response and CSD Waterfall Plots
Post by: rhythmdevils on November 19, 2012, 08:52:29 PM
I don't know what the insides of the KODA2 look like but you should have a better starting place than the stock T50rp cup unless he did something weird.  I imagine the koda baffle is at least more rigid. 
Title: Re: Koda T50RP Frequency Response and CSD Waterfall Plots
Post by: LFF on November 19, 2012, 10:51:15 PM
I don't know what the insides of the KODA2 look like but you should have a better starting place than the stock T50rp cup unless he did something weird.  I imagine the koda baffle is at least more rigid.

Stock is better....KODA is well.... :vomit: and  poo
Title: Re: Koda T50RP Frequency Response and CSD Waterfall Plots
Post by: rhythmdevils on November 19, 2012, 10:54:43 PM
The enclosure isn't even better than the stock T50rp?  I would hope it would at least not have that bloody screw housing sticking up at the driver, and have a more rigid baffle and with the right damping could be better than a T50rp with stock housing. 
Title: Re: Koda T50RP Frequency Response and CSD Waterfall Plots
Post by: devouringone3 on November 20, 2012, 12:49:53 AM
His acrylic as a baffle is thick and super stiff.

The interior and the exterior are still like he shown them in the first series of photos (second series are pictures of the Koda^1) in his main post:
http://www.head-fi.org/t/582736/koda-2-k-nigs-ortho-dynamic-acrylic-headphones#post_7927522


By the way my pair is supposed to be less bad, lol:
(http://cdn.head-fi.org/e/e3/900x900px-LL-e3db0c92_KODA2MK-IIdevouringone3.png)
(his measurements)

In grey are the stock Koda^2, and apparently only his pair and mine were "fine tuned to 'MK-II' " like that. He was doing so hoping to correct/improve the 200 Hz dip. This fine tuning consist of (and I'm quoting him from the Koda thread): "A smaller hole on the dampening on the back [of the driver or the chamber, it's unspecified] and smaller bass port." So the internals (other than the "dampening on the back") should have remained unchanged.

I can see the smaller bass port, being 1/3 of the original size:
(http://s8.postimage.org/4v06bdigl/DSCN8416.jpg)

Covering what is left of the bass port does remove some if not all of the deeper bass.
Title: Re: Koda T50RP Frequency Response and CSD Waterfall Plots
Post by: wiinippongamer on November 20, 2012, 01:02:18 AM
The naked driver is likely a big part of the sonic issues, I'd cover the drivers with coffee filter material or similar and put on some thicker/cushier pads to compensate for the loss of bass. Getting rid of the reflex dot and putting foam in it's place could be good too.
Title: Re: Koda T50RP Frequency Response and CSD Waterfall Plots
Post by: LFF on November 20, 2012, 01:20:03 AM
Yeah...I hate to burst your bubble but the set that Purrin measured is also a MKII.

The baffle is thick but the cups are a bit fragile. I have had them break apart three times already. I got fed up and just crazy glued the damn things together.

While they might be rigid, the inner volume is just not there. 

They are good looking though.

These headphones remind me of the typical Californian girl\stripper....so nice to look at but empty and worthless when it comes to actual value.


Title: Re: Koda T50RP Frequency Response and CSD Waterfall Plots
Post by: rhythmdevils on November 20, 2012, 01:25:26 AM
The cup volume is smaller than stock? 

Naked drivers alone wouldn't cause that dip, he must have something really funky going on. 
Title: Re: Koda T50RP Frequency Response and CSD Waterfall Plots
Post by: LFF on November 20, 2012, 03:03:09 AM
The cup volume is smaller than stock? 

Naked drivers alone wouldn't cause that dip, he must have something really funky going on.

Yes...smaller than stock.

It's his dampening.
Title: Re: Koda T50RP Frequency Response and CSD Waterfall Plots
Post by: devouringone3 on November 20, 2012, 03:47:45 AM
That would be a good news, his dampening is more removable / modifiable than his whole cups. Have you tried doing anything to your pair while you had it?
Title: Re: Koda T50RP Frequency Response and CSD Waterfall Plots
Post by: Hands on November 20, 2012, 07:30:32 AM
Yeah...I hate to burst your bubble but the set that Purrin measured is also a MKII.

You're sure? The FR measurements linked on the front page seem to match up with the earlier revision. Perhaps these improvements came after the MKII designation? I can't remember how it ended up playing out, but it really does look like the measurements purrin has up are for the much more broken version.
Title: Re: Koda T50RP Frequency Response and CSD Waterfall Plots
Post by: devouringone3 on November 20, 2012, 08:00:41 AM
The Koda^2-MKII are broken and sounds way too wonky for me to want to use them at all. They have a gross flaw in their midrange that (best example I can give) makes piano (but vocals, or anything, and too many things too, that fall into this frequency band I realize) piercing sounding and very harsh.

It's a weird flaw, that doesn't have anything to do with the stock T50RP. *Edit, I am guessing that this has got to do with that gigantic 650 Hz mountain of resonance in the CSD plot, right? I just noticed it

Other than that I think they have nice sub bass and okay T50RP highs? I would need to re-listen to them, I don't remember pushing the volume up much, maybe it was just too unpleasant to even think about trying it. I don't have them with me this semester, but soon enough I do intend to see if I can "fix" it; right now I don't have the mean and knowledge to do it, but I'll read and think more, and probably ask for your help ;) and Head-Fi's too.

If LFF tells me he have already tried and deemed them unsolvable because of their cup design... well... lol, I don't know, I'm stuck with them, so I'll still try anyway.
Title: Re: Koda T50RP Frequency Response and CSD Waterfall Plots
Post by: Deep Funk on November 20, 2012, 10:59:43 AM
This reminds me of a friend who bought very expensive tailor made shoes but they weren't comfortable in the least while I bought cheap shoes that only needed an inner support sole and two years on they're still good :-Z

How much hype did this Koda-thing need?