solderdude
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Post by solderdude on Jun 26, 2013 13:50:49 GMT
Measurements from Micks T50RP with SRH-840 pads and mods done (only the felt in front of the driver was not present yet). Excellent driver matching (my earlier measurements were wrong as one on one side the seal wasn't perfect
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solderdude
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Post by solderdude on Jul 3, 2013 17:49:53 GMT
Finished the filter... Some plots. Note I adjusted the scale and each division is now 10dB (a doubling in perceived loudness), on the older plot above it is 5dB ! These plots are taken without any smoothing. Some of the smaller 'ridges' are not audible and is why most plots use 'smoothing' to iron them out and present a nicer picture that more closely matches what we hear. I like to show warts and all but some of the warts come from the measurement method and may not be there when on an actual head. As some wanted to know what exactly the effect of the medical felt in FRONT of the driver does.. Purple = with felt, blue is without felt in front of the driver. As you can see it only lowers the 8kHz peak by a few dB (that needs to be lowered as well and is the main reason) and doesn't really affect the rest of the highs nor mids. Interestingly it affects the lows. And in a good way at that. The resonance is lowered and the subsonic-lows are increased slightly. This is because of the added damping which obviously helps there too. Below the left driver without a filter (but with felt over the driver) + the actual filter response. As you can see the filter has the opposite curve the headphone itself has. Because of this they 'cancel' out. The plot below shows the left channel again but shows an unfiltered (but modified with felt on the driver) together with the same driver but the filter switched on (active) below Heliharris's T50RP modified with SRH-840 velours pads and active filter for both channels. the slight difference in the highs is a measurement error but I forgot to update the picture so it shows small differences in the highs between L and R that are not really there. quite extended now and measures between 10Hz (far below inaudible) and 20kHz (far above the 16kHz most can just hear, unless you are young) The lows are slightly accentuated so it is easier to listen to it with lower SPL. It is in NO way obvious though and as the lift is just a few dB it doesn't sound like a 'lift' it does make it fuller sounding. In short: sounds GREAT, which of course is the intention. Here is a picture of the filterbox... Need to pack it and ship it one of these days...
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Post by jhelms on Jul 4, 2013 2:10:40 GMT
Man that looks good!
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juke
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Post by juke on Jul 4, 2013 10:14:15 GMT
It's great having your own personalised 'phone/filter combination Mick, glad it worked out in the end.
Any chance of a pic of the other end? I've just bought the same box and haven't drilled it yet so just curious to see how you fitted in the plugs and sockets on the other end.
Syd
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juke
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Post by juke on Jul 4, 2013 13:16:33 GMT
Not urgent Mick, I remember your case being really neat but not the details. I thought I was done with case making but decided to use a Hammond instead of the cheapo I had bought for the TP50 filter. The original short Hammond was no good after the extra section was added to the back of my Mk1 board.
My HE6 filter is in the same case as yours already, having seen Dicky's neat example.
I'll keep your offer in mind Mick!
Syd
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solderdude
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Post by solderdude on Jul 4, 2013 16:00:39 GMT
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Post by solderdude on Jul 4, 2013 18:25:22 GMT
With smaller RCA's (can use thick RCA plugs in that case) you can just fit 4 RCA's and the power supply inlet on the back. In the frontpanel you can mount the LED(s) and switch(es).
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Post by Deleted on Jul 4, 2013 19:00:48 GMT
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solderdude
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Post by solderdude on Jul 4, 2013 20:21:53 GMT
The Mad dogs and Paradox headphones still need a filter as well. They are just modified T50's and still exhibit roll-off in the highs and the 3kHz area.
The Maddogs are more affordable than the Paradox but the latter seems to be flatter.
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Rabbit
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Post by Rabbit on Jul 4, 2013 20:35:22 GMT
Aha .... I've heard a Paradox now and I can barely tell your modded headphone from them Frans. They also show the same roll off and so are better with the filter.
£196 plus £16 shipping and any import taxes = quite a bit. £212 + import tax. Is that 17.5% in UK? Somewhere areound £240 - £250? It's getting expensive ... and don't forget a healthy output from an amp that is needed for them.
For me, at that price, the HD600 comes in to play tbh. That one is still a good value headphone and has a nice even response too.
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solderdude
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Post by solderdude on Jul 5, 2013 4:40:12 GMT
The latest measurements of Purrin also show (just like Tyll's measurements showed earlier) that the Paradox doesn't measure as flat as Purrin's first measurements seemed to suggest.
I have always thought it was weird Luis got them to measure flat by just stuffing them and adding pads. Turns out they aren't as flat after all but also show the 4kHz dip and the roll-off above 10kHz.
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Rabbit
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Post by Rabbit on Jul 5, 2013 8:07:11 GMT
The latest measurements of Purrin also show (just like Tyll's measurements showed earlier) that the Paradox doesn't measure as flat as Purrin's first measurements seemed to suggest. I have always thought it was weird Luis got them to measure flat by just stuffing them and adding pads. Turns out they aren't as flat after all but also show the 4kHz dip and the roll-off above 10kHz. Exactly, Frans. I couldn't really tell them apart if I'm honest. I think the guy who lent me them paid a lot of money for them too so I was under pressure to feel that they were flatter for his sake, but frankly, they're not. I didn't say too much on here since I didn't want to upset anyone who may have bought one. They cost more than the one in the advert. I think more like £300 - £400. I guess the justification is the time spent fiddling around to get them as flat as possible; especially given that they can be slightly variable. I know you spent some time on mine. It's great that at the forefront of headphone evaluation is this trend to actually measure them like speakers. It's getting the method to tally with what the ears hear though, I know, so it's very problematic. At least if some kind of standard is set for what constitutes a neutral headphone, then we have a terrific comparative resource in order to evaluate headphones a little bit more accurately before buying them on subjective recommendations. Until recently, the only way to get any idea of what a headphone sounds like was to read a review. There is of course, also the view that measurements mean nothing etc - but you only have to hear the T40 and look at that graph to realise that perhaps some people may be in denial and seem to not like a clear cut indication of what a headphone does in reality. Subjective reviewing leaves the market open to purposely colouring headphones so that reviews are glowing if individuals like certain sounds, but with a standardised kind of measurement, there is more pressure on more responsible manufacturers to produce something closer to flat perhaps. (Much like speakers and amps) Of course, it's not JUST the FR measurements that constitute a great sound, but I think once you hear a flattish headphone, you become really aware of problems in many that are quite highly regarded. it's discovering the standard way to measure that has been problematic for non standard heads, but I must admit, this aspect of headphones has really interested me a great deal; especially after hearing the T40 tweaked to as flat as dammit. That has revealed SO many flaws in headphone response for me. It's also made me realise just how close the Senn 600 series get and given me more respect for those headphones, that I didn't have before tbh. It kind of changes your perspective on what constitutes a good headphone.
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juke
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Post by juke on Jul 5, 2013 11:26:17 GMT
Thanks for the extra pic Frans, that's a neat installation.
What way is the PSU arranged? I have a three wire input so was expecting to see a different socket, XLR type or such but they are much bulkier of course.
Syd
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solderdude
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Post by solderdude on Jul 5, 2013 12:36:12 GMT
The PS in this case is a 12V DC Pinky that feeds the internal DCDC converter. It is isolated by the DCDC converter as well as the AC transformer.
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solderdude
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Post by solderdude on Jul 11, 2013 7:20:49 GMT
According to the tracking number the T50RP with filter is on it's way to the U.K.
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