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Review: CharterOak Acoustics SP-1 (GMP 450 Pro) - Page 9

post #121 of 356
I honestly had enough dealing with shady sellers and vendors in the past 1.5 months (Earsonics, Yulong, Musiland, Fischer Audio/GD etc). I don't think I can take another one right now.
We'll see what happens at 100h magically-wonderful-burn-in/ connecting them to a non PoS DAC/AMP

500
and here's the EQ diagram of what I have to do to EQ them to the same FR as my SR-507 which is widely considered neutral. (at this point there is no annoying bass or mids peak, but they still sound veiled(resolution-wise), but that's just the underamping/MD11, I guess)
Edited by svyr - 3/23/11 at 6:29am
post #122 of 356

 

Here's the frequency response graph of the GMP 450 Pro:

 

GMP450Pro_SPL.jpg

 

As you can see it has a prety linear response from lows to mids, the response drops at around 3000 - 5000Hz due to the fact that our hearing is most sensitive at those ranges.

 

Hearing a sinus sweep on my GMP 450 it certainly sounds pretty flat, just some minor flutuation on high midrange, lower treble and a peak at 9700Hz.

 

I have actually been experimenting with equalization to try to make the frequency response perfectly flat to my ears and I have been getting some very rewarding results by flatening out the 3000 - 10000Hz range.

By doing this some of the brightness and harshness in the treble is tamed down and some instruments sound more natural to my ears, particularly cymbals and drums. Soundstage also seems somewhat more coherent.

I prefer to cut than to add or boost frequencies.

I'm using the Electri-Q VST with foobar2000.

I'll report about this on my write-up.

 

Looking at your equalization settings, there doesn't seem to be any sharp peak (the range you adjusted is very wide), maybe you are actually perceiving the sound like that...

 

I'll experiment your settings on my equalization curve to see what I get.

 

When you say "veiled(resolution wise)", what do you exactly mean?

Are you accustomed to bright headphones?

 

Still, you really shouldn't worry about German Maestro customer service, I mean it.

post #123 of 356
Quote:
Originally Posted by kkl10 View Post

 

Here's the frequency response graph of the GMP 450 Pro:

 

GMP450Pro_SPL.jpg

 

As you can see it has a prety linear response from lows to mids, the response drops at around 3000 - 5000Hz due to the fact that our hearing is most sensitive at those ranges.

 

Hearing a sinus sweep on my GMP 450 it certainly sounds pretty flat, just some minor flutuation on high midrange, lower treble and a peak at 9700Hz.

 

I have actually been experimenting with equalization to try to make the frequency response perfectly flat to my ears and I have been getting some very rewarding results by flatening out the 3000 - 10000Hz range.

By doing this some of the brightness and harshness in the treble is tamed down and some instruments sound more natural to my ears, particularly cymbals and drums. Soundstage also seems somewhat more coherent.

I prefer to cut than to add or boost frequencies.

I'm using the Electri-Q VST with foobar2000.

I'll report about this on my write-up.

 

Looking at your equalization settings, there doesn't seem to be any sharp peak (the range you adjusted is very wide), maybe you are actually perceiving the sound like that...

 

I'll experiment your settings on my equalization curve to see what I get.

 

When you say "veiled(resolution wise)", what do you exactly mean?

Are you accustomed to bright headphones?

 

Still, you really shouldn't worry about German Maestro customer service, I mean it.


Interesting. I'd say what I EQed in the mids/upper bass is consistent with the chart. The FR chart looks to me like a sharp 5db+ peak in the mids (700-ish to 3000hz) + a very large one (8-9) in the highs. I've EQed the mids down fairly consistently and the upper bass rising in the FR.

Don't really mind the highs,since both DT48e and SR-507 are fairly bright there. (+ I've only matched the EQ on the mids/upper bass so far). I suppose, for highs - my version of 'neutral' is probably someone else's of bright.
Edited by svyr - 3/23/11 at 4:37pm
post #124 of 356

 

svyr, I have been experimenting with your equalization settings in combinations with my previous settings and have been able to subjectively improve the sound quality! Thank you! Now the frequency response is even flatter to my ears.

 

Your issue with the peak at the midrange is probably your perception of the midrange forwardness of this headphone, probably your ears are better educated than mine because I wasn't able to realise how forward the midrange was before I applied your settings.

 

Previously I thought that the response at the midrange was in level with the rest of the spectrum, but now I just realised that it is louder, so I'm actualy detecting the midrange peak just like you did, thanks to your settings...

Probably I wasn't discerning correctly the loudness of the entire spectrum...

 

After the equalization the response is much flatter to my ears and naturaly everything sounds better, some instruments and vocals are less upfront yet better defined and soundstage opens up even more...

Comparing to the unequalized state, it's noticeable that the coloration and ressonances caused by the earpads themselves (which make the sound somewhat claustrophobic, veiled and narrow sounding) and the closed cups are greatly reduced.

Maybe the closed back design sonic shortcomings and the midrange forwardness made you think that there was some distortion on the midrange?

 

I still don't understand how you can find the GMP 450 Pro dull, veiled, dead, so if it's not faulty then your concept of neutral is definitelly my concept of bright and I'm not sure that the GMP 450 Pro will become has bright has you'd like with just an amp... unless they are seriously underpowered, which I find hard to believe because my Yulong D100 doesn't seem to underpower them as bad as to make them dead,  veiled or dull... yet I must admit that it's my first devices of the kind and it's my subjective opinion.

 

A different set of earpads, the big oval perforated ones or the round velour perforated ones (both included on my last pictures) do improve the perception of brightness and resolution and dehemphasize the bass and lower midrange, but they do not provide as flat frequency response on the higher frequencies as the stock earpads (easily fixable with parametric equalization).

However both of these earpads are deeper than the stock ones and will put the drivers further way from your ears, thus the necessity for higher amplification power to get the same subjective volume, specially the round velour perforated earpads(41-6049).

 

If you don't want to buy new earpads you could try to use the earpads of your Beyerdynamic T5p on the GMP 450 Pro and see if they improve the sound... that would be interesting... :P

By the way, why are you selling the T5p?

 

post #125 of 356
>Maybe the closed back design sonic shortcomings and the midrange forwardness made you think that there was some distortion on the midrange?I still don't understand how you can find the GMP 450 Pro dull, veiled, dead

it's probably just that it's 4-5 db louder and that MD11 is horrible to begin with and gets more horrible with higher impedance HP - hence the distortion and the perceived lack of detail (compared to T5p and DT48e). D100 is a lot brighter than musiland and might not distort as badly as it on higher impedance cans. IDK (my replacement D100 is still in transit)


>By the way, why are you selling the T5p?

because I need a TV and a couch, and a portable amp for work.


> but they do not provide as flat frequency response on the higher frequencies as the stock earpads (easily fixable with parametric equalization).

You only get EQ on so many programs. Unless your DAC has a build in parametric EQ with enough bands which is somewhat unlikely for higher end ones. I've also seen faulty EQ implementations that add significant noise or distortion. Keep in mind, the time you spend playing with them to EQ them, re-filter them (pads/etc) and or re-dampen them is also money, and you could probably just buy a different set. EQ to many people here means the headphone is pretty much dead. I don't mind it that much especially if it's just the bass, but still. On the other hand it does give you the benefit of aligning the HP FR with your ELCs.


>could try to use the earpads of your Beyerdynamic T5p

probably could, but too concerned that I might tear them/tear them off or something while taking them off.
post #126 of 356
Quote:
Originally Posted by svyr View Post


You only get EQ on so many programs. Unless your DAC has a build in parametric EQ with enough bands which is somewhat unlikely for higher end ones. I've also seen faulty EQ implementations that add significant noise or distortion. Keep in mind, the time you spend playing with them to EQ them, re-filter them (pads/etc) and or re-dampen them is also money, and you could probably just buy a different set. EQ to many people here means the headphone is pretty much dead. I don't mind it that much especially if it's just the bass, but still.


 

 

>On the other hand it does give you the benefit of aligning the HP FR with your ELCs.


And this is what really matters to me, I don't think it would be fair to the headphones if I didn't provide them the chance to really show of their best performance.

 

Not that all this modding and tuning is really necessary to make them sound good to my ears - they already sound very good without any mod, just using the big oval earpads on top of the stock ones makes them worth of the roughly 370 Euros (more than my initial budget of 230 Euros) I spent with the headphones and all the additional acessories - but as I have been saying from the beginning I want the most transparent/accurate sound possible from the only headphone I'm going to use through a long time for the purposes of music enjoyment and audio work and after a long time of search, this headphone was the best choice I could make for a starting point because of several key characteristics I was looking for.

After this starting point all the time and money spent with modding and tuning is very worth and short compared to the time I'm going to use these headphones.

I'm just preparing them for the future.

 

In my particular situation buying another headphone wouldn't really make much sense, however, if I was richier it would be different.

 

Still I think that one as to at least give a chance for the headphone to show it's potential so go get those T5p earpads and put them on the GMP!

Just kidding...

 

 


Edited by kkl10 - 3/26/11 at 8:06am
post #127 of 356

I have always been a sucker for the midrange...

 

Both of your results are making me think the forward midranges of the GMP450 PRO are the reason I like it so much.

 

Interesting, if I find some time I will try out your EQ settings...

post #128 of 356

 

R-Audiohead, you should try with the EQ settings that make the frequency response as flat as possible to your ears, if you want the most accurate sound.

To try with the settings of another person is not really recomended because everyones sound perception is different.

If you really want to know how your headphones improve with proper equalization, if you are serious about doing it, it might require some time and lot of work if you are not used to equalise.

A simple graphic EQ won't be enough... you'll probably need a parametric equalizer.

I started from this good tutorial.

 

I'm going to show my current EQ curve and settings (still needing some work) for the GMP 450 Pro with the stock earpads.

 

Equalização German Maestro GMP 450 Pro.png

 

Settings:

 

Freq. - 60Hz

Gain - -6dB

Bandwidth - 4

 

Freq. - 400Hz

Gain - 1.3dB

Bandwidth - 2.6

 

Freq. - 1000Hz

Gain - -10.5dB

Bandwidth - 2.9

 

Freq. - 2210Hz

Gain - -2.6dB

Bandwidth - 1

 

Freq. - 3500Hz

Gain - 2dB

Bandwidth - 0.1

 

Freq. - 5550Hz

Gain - -7.5

Bandwidth - 1

 

Freq. - 9700Hz

Gain - -10

Bandwidth - 0.2

 

Freq. - 13000Hz

Gain - -4

Bandwidth - 0.1

 

As you can see, this graph shows that I tried to cut much more than to boost frequencies, I tried to match all the frequency spectrum volume to the least loud frequencies without to much boost... a somewhat unortodox method... but I will eventually create another more conventional curve since there are no big benefits by using only cuts on this context...

 

I'm using vaious sinus sweeps, pink noise, SineGen, Electri-Q parametric equalizer which allows up to 64 bands.

If you really want to do efficient equalization I recommend parametric equalizer instead of graphic.

The more bands the more control and precision you'll have on your EQ curve.

Electri-Q VST is a good parametric equalizer with a free version, it can be used with any media player with VST compability (foobar2000 requires a VST wrapper).

But there are other good and free parametric equalizers.

If you choose a good one, there will be no need to worry about colorations or distortions to the audio signal.

If done right the benefits of EQying far outweight any possible detriments to the sound quality.

 

 

post #129 of 356

Much appreciated.

 

When time permits (Mid-May) I'll certainly be spending some serious time with this (and of course sharing my results!).  I may be only scratching the surface with my SP-1s.

 

I'll take your word for it on the EQ... I've used graphic EQs on external setups before quite heavily and I find exactly what you mentioned... that the benefits the EQ provide are limited by potential coloration.  I always found myself removing the EQ and moving to the amps specific frequency gains and playing with active crossovers with WAY better results.  Active crossover + hardware tuning always wins over graphic EQ, even if 10-band.

post #130 of 356
Since I got the replacement D100. For GMP 450 Pro + D100... It's nicer than 450+MD11 - a lot clearer and goes loud enough even with non-normalized old classical DVDs (there's even a bit of volume left biggrin.gif after it's deafening), the noise floor is a lot lower on D100.
The volume is loud enough for most material - even classical. Unfortunately, the lower mids and upper bass bump is still there though, making them very suspect to use without EQ. The relatively bright D100 amp makes that hump even more noticeable and painful.
So by the looks of it, the amp section on MD11 really doesn't handle high impedance cans well (even higher noise and darker sound than usual)
post #131 of 356

 

That's what I'm getting with my D100 + GMP 450 Pro: loud enough for most music and a somewhat bright midrange forwardness.

The midrange forwardness of the GMP 450 Pro won't disappear with an amp, it's part of the the headphones character.

 

Do you still feel that the GMP 450 Pro is being underpowered by the D100?

Probably it's not up to the same level of sound quality as the DT-48 isn't it?

It would be very interesting to see how's your D100 + EQed GMP 450 Pro combination compared to the DT-48... at least before you sell them, since you don't seem to like the sound of the stock GMP 450 Pro that much.

 

As far as I can tell the EQed GMP 450 Pro is a tier up in sound quality in comparison to unEQed on balance (obviously), clarity and separation and spatial resolution (these three improve dramatically), detail (real detail comes out, not false detail created by the ressonances and coloration), sub-bass comes to live, etc...

 

Here's my improved EQ curve for the stock GMP 450 Pro: I'm still improving it over and over till perfection.

 

Equalização German Maestro GMP 450 Pro2.png

 

 

 

post #132 of 356
Quote:
Originally Posted by kkl10 View Post

 

That's what I'm getting with my D100 + GMP 450 Pro: loud enough for most music and a somewhat bright midrange forwardness.

The midrange forwardness of the GMP 450 Pro won't disappear with an amp, it's part of the the headphones character.

 

Do you still feel that the GMP 450 Pro is being underpowered by the D100?

Probably it's not up to the same level of sound quality as the DT-48 isn't it?

It would be very interesting to see how's your D100 + EQed GMP 450 Pro combination compared to the DT-48... at least before you sell them, since you don't seem to like the sound of the stock GMP 450 Pro that much.

 

As far as I can tell the EQed GMP 450 Pro is a tier up in sound quality in comparison to unEQed on balance (obviously), clarity and separation and spatial resolution (these three improve dramatically), detail (real detail comes out, not false detail created by the ressonances and coloration), sub-bass comes to live, etc...

 

Here's my improved EQ curve for the stock GMP 450 Pro: I'm still improving it over and over till perfection.

 

Equalização German Maestro GMP 450 Pro2.png

 

 

 


> Do you still feel that the GMP 450 Pro is being underpowered by the D100?

no.


>The midrange forwardness of the GMP 450 Pro won't disappear with an amp, it's part of the the headphones character.

I think the graph above conclusively proves that biggrin.gif. I wouldn't say 'character' - flaw.


> Probably it's not up to the same level of sound quality as the DT-48 isn't it?

apples and oranges


>It would be very interesting to see how's your D100 + EQed GMP 450 Pro combination compared to the DT-48... at least before you sell them, since you don't seem to like the sound of the stock GMP 450 Pro that much.

DT48e is strange as well and benefits from EQing (eqing up the bass roll-off and on some tracks eqing down the highs)... Other than that DT48e = more midrange detail, partly because of the much tighter seal.
Edited by svyr - 4/9/11 at 9:09am
post #133 of 356

 

svyr, I see that you already received your FA-002w.

 

I suspect that it might sound better, or at least more coherent, than the GMP because it is said to have a similar sonic signature to the Sennheiser HD600 which is known for it's relatively flat frequency response and because is not as dificult to drive.

But I'm not sure about it's driver resolution... from all I've read I think it's inferior, that's why i choosed to buy the GMP instead of the FA-003.

 

Please give here some input on how it compares sonically to the GMP 450 Pro when you can.

Maybe after burn-in, since it seems to sound strange to you for now...


Edited by kkl10 - 4/11/11 at 2:47pm
post #134 of 356

Sometimes certain signatures just don't match up well with people...

 

Still loving my oaks.

post #135 of 356

It seems like Headfonia is going to publish reviews of the GMPs 400, 435, and 450 Pro soon.

Hope these get to be compared with K701, DT 880, HD600 or other mid to high end cans by those experienced hears.

I wish I could tell the reviewer to get the big oval earpads to doublepad those GMPs to coorroborate my findings on sound quality improvement.

 

Equalization has occupied me very much these days.

 

Here's my improved EQ curve for the stock GMP 450 Pro, still improvable:

 

Equalização German Maestro GMP 450 Pro9.png

 

 

That boost on the highest frequencies gave the GMP 450 an improvement on imaging and sense of presence/realness as if the music was being played right here with me and not reproduced by the headphone.

 

 

And the best sound I could get from the GMP 450 Pro comes from this configuration:

Doublepadded with 41 - 6050 earpads, big oval ones with the following EQ curve

 

Equalização German Maestro GMP 450 Pro Dupla almofada2.png

 

In this configuration I hear a sinus sweep from 20 - 18000Hz as almost perfectly flat. But still improvable...

The doublepadding contributes to a better tonal balance as the curve shows, this combined with EQ takes the GMP 450 Pro (and I feel comfident to say the GMP 400 to) into a whole new tier in sound quality!

 

My hair has been growing again, lol, so these EQ curves will need to be modified over time to accomodate the changes on sound signature made by the progressively looser fit and seal.

 

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