Review: CharterOak Acoustics SP-1 (GMP 450 Pro) - Page 7

Just got the QP400 in.

I think this headphone will suit your needs much better.

Given you love the GMP 450 PRO except for the fact that it is indeed closed, the QP400 sounds perfect - the driver is identical, the clamping force is slightly greater, and the soundstage is quite large.

To be honest, it lost a little resolution and speed, but the open design really livens up the vocal ranges.

More on this as I A/B with more tracks.

My roomate and I plan on posting something, as mentioned before.
 

Quote:

Originally Posted by kkl10 

 

OK now, I believe to have started to understant the sound of the GMP better.

As I've said before, this is my first full sized headphone so they are "educating" my ears in a different way of IEMs... and in a better way I believe.

 

Recessed bass, brightness and other aspects that confused me at first are now a non issue because my ears were definitely biased.

The seal and the proximity of the driver to the ear canal of IEMs has to do with this, since that gives one a different perception of sound.

Stronger and more direct sound pressure level at the ear canal of IEMs provide smaller soundstage, stronger bass... a "closer" sound than the GMP.

I perceive the GMPs sound as naturally bigger and actually more well balanced and spacially realistic. Not only bass, but all the frequency spectrum is perceived as less upfront, more "laid back", distant. There's more air, breath and space on which the sound can develop. It's, in a way, a more "open" sound.

I say "in a way" because, despite the spacial perception improvement, I can still sense that the GMP is a closed headphone when comparing the "purity" of sound with IEMs.

Listening to a voice on IEMs for example gives me the feeling that the voice Is on a open space, with no phisical limits and with the GMP it's like the voice Is within a ressonant room. I think it irks slightly the excelent tonal accuracy of the GMP.

At first I confused the bigger, spacier and less "pure" sound/tone of the GMP with brightness but now I understand and like quite a lot what I'm hearing through this GMP 450 Pro.

It's, also, not a basslight headphone by any means, it has a much more realistic bass output than IEMs, just that. When the music demands the bass shows very appreciable weight and punch.

Don't get me wrong, it is a bright sounding headphone but not overly so as I thought.

 

I'm loving it with classical music, jazz, folk... actually any kind of acoustical music. This headphone is really marvelous with voices and instruments.

Now I'm fiinding that I, almost, can't go back to IEMs with this kind of music, but with some synthesized or electronic music I still prefer the presentation given by IEMs.(Let me note here that I'm refering mostly to my slighly modded Head Direct RE0 IEM, since it's the only one able to somehow keep up with the level of sound resolution of the GMP 450 Pro)

 

What has come up from my better understanding of this headphone sound, is that it is a very balanced and neutral sounding headphone. It's a fairly relaxing sounding headphone yet very engaging and athletic. Not as smooth as my Head Direct RE0, but more textured and slightly more detailed I believe. Great spacial resolution.

 

Very confortable headphone on the head indeed. A bit loose could use some more clamping force.

More listening still required though.

 

Will keep my eyes open for that thread R-Audiohead.

And looking forward on impressions of the QP 400 vs SP-1.

Quote:

Originally Posted by joelpearce 

There's no question, if the 450s sound too closed to you, you are and will always be an open headphone guy.

 

I think you're right that all headphones come with some trade-offs, and that's one of the trade-offs you get every time with closed cans, in exchange for isolation.  At the same time, even open headphones can't seem to compete with speakers for soundstage and imaging, which is maybe why we get so obsessed in general here at head-fi.

 

We all want to get as close as possible to perfection, but there are inherent flaws in the overall design structure of headphones in the first place.  It's the quest for the Holy Grail, but it doesn't really exist.

I remember you saying you had ordered beyer pads for these SP-1s.

Did those pads fit properly? I'm curious, because I don't think I would track down a QP400 just to snag the pads off of them.

Fair enough!

Thanks for the input.

Still loving these cans...

So far the QP400s are dominating in the vocal ranges but are a little lighter on the strings and especially piano.  SP-1s seem a little more nimble as well so far.

Still a lot to do before I say/post anything for sure!
 

Quote:

Originally Posted by joelpearce 

Yeah, they sounded like poop.

 

Oddly enough, the oval pads (really flat ones with small holes) that the Charteroaks shipped with had by far the MOST bass, as well as a more open sound.  The DT770 pads didn't work with them at all (though they are really nice on the DBI Pro 700).  

 

German Maestro does sell pads at their store, but I would not recommend putting pads from closed headphones on open headphones or vice versa.  Like the construction of the drivers and housings, they have very different sonic goals, and usually don't play nice when put on the wrong type of cans.

Guys, I believe to have made a major discovery on the quality of the drivers of GMP 450 Pro:

Little before I posted about my disappointment over the closed sound of the 450 Pro I had began to think in the possibility of modding it in order to be able to perceive the real potential of the driver.

What I ended up doing is so simple and it is showing that the driver is so good that I'm actually having a hard time believing it!

Unfortunatelly, I have no way to take pictures, so I'll try my best to explain what I did... which is actually very simple.

1. First I removed the earpads;

2. Then I disassembled the headphone earcups by unscrewing the three screws that were covered by the earpads; (no need to remove the screws from their places after unscrewing)

The eacups are composed of two parts:

- the back of the earcup, which is filled with a thick layer of sponge like material,

- and the driver assembly that is part of the structure where the earpads are mounted. There is another thick layer of the same sponge material attached/glued to the back of the driver assembly (the driver itself probably but not sure...).

So the interior of the earcups is completely filled with sponge and there are no vents , apparently sealed.

By disassembling the earcups, these are also separated from the headband structure, because both parts of the earcups, when joined to each other, are securing the elastics that suspend them on the rings of the headband.

Still following me?

3. After disassembling the earcups I just reattached the earpads to their places (the front part of the driver assembly structure).

So I ended up with something which has a earpad on one side and a sponge on the other.

4. With my hands I placed the "open driver assembly structure" at my ears to listen to the differences in sound.

And the driver revealed itself in a completely different way! And in a much better way to be frank!

All the issues I had with the closed headphone signature were completely gone and this time everything had now proper tone and timbre, no nasty coloration anymore and clearly better clarity and intelligibility despite the radical sound signature change.

The most surprising to me was the way that sound was presented with this opened back improvisation of mine:

From a bright, colored, slightly bass shy, distant, ressonant, harsh, overly sibilant, nimble, overly analitycal sound signature made by the close earcups,

it became much more meaty and natural sounding with much weightier bass, lush and highly resolute midrange and more laid back, smoother but very detailed treble, much more natural tone and timbre of every kind of sounds, more coherent, real and rich sound with no less detail than before and more nuances to appreciate. Spacial resolution, air and breath also improved greatly as expected. Now it didn't sound bright at all but instead dark yet possibly closer to perfectly neutral.

I really can't express in words some of the great improvements in sound quality of the opened back driver over the closed back driver.

By covering the back driver sponges with my hands I could more or less create the same degrading effects that the earcups backs were doing to the sound of the driver.

Now I'm wondering even more how the GMP 400 might sound...

Now the sound I'm getting is very similar in signature to my modded Head Direct RE0, and to a lesser extent the Sennheiser PX100, but with more resolution and refinement overall.

It would be great if someone else could do this to his/her SP-1 or GMP 450 Pro to corroborate my findings.

I still haven't tried this configuration with the other earpads... only the stock ones which are the darker and bassier sounding.

Will try to take some pictures some way or another.

I must say that the sound now is so good that if you guys consider the Charteroak SP-1/GMP 450 Pro deserving of it's 350$ price tag in it's stock form, then a open headphone based on this configuration that I'm enjoying now would be worth at least 500$ just for the sound!

It would be interesting to see this done also on the MB Quart QP 400.

Now I love my GMP 450 Pro so much! :)

CLOSED HEADPHONE? MY ASS!!  XD

^

I guess you made yourself a GMP400...

Now it's time to try out the different German Maestro earpads they offer, because they will alter the sound as well.

I did it the opposite way with my DT880 doing the NoXter mod, by stuffing the earcups (and changing earpads) in order to make them closed.

Here are some pictures of my GMP 450 Pro disassembled earcups.

I apologize for the poor quality! It will have to do for now...

The GMP 450 Pro in it's stock form.

That screwdriver on top is the only tool necessary to unmount the earcups.

First I took off the earpads, then unscrewed the three screws left uncovered.

And the driver assembly structure was out.

In more detail:

The closed enclosures can still be secured by the four elastic cords after removing the driver assembly structure, but they can be smoothly pushed out with no problem.

Then I reattached some earpads in place and I was done with it!

The perforated round velour earpads for example.

The GMP 450 Pro fully opened sounds much, much better now!

The "open earcups" cannot be attached in any way to the headband rings, they just remain loose incide there, but the clamping force is enough to not let them fall down from my head. Fairly secure and confortable though.

So this is what I have right now...

Not sure what to do from here yet... perforate the stock enclosures or try to build some new open ones...

Covering the headphone with my hands or the closed enclosures while listening to music shows clearly how the sound improves from close to open.

Obviously it sounds really open now, tone, timbre, dinamic range, spacial perception, neutrality and transparency are greatly improved.

It sounds bigger and real now... can't express it better than this...

Now I can enjoy any kind off music with the GMP 450 Pro.

I was a bit surprised to hear the bass become more prominent without the enclosure... usually it's the other way around:

closed headphones usually have more bass than it's open counterparts.

Now it even makes my RE0 IEM sound bad. =/

CORRECTION: I said before that the bass became much weightier and that the sounds is dark in this configuration but that's wrong, the bass has indeed a stronger output but not to the point of changing the sonic character to Dark, it is just less bright and thin sounding and more full bodied and natural. I also said that the sound signature became identical to my Head Direct RE0 and PX100 which is also wrong! I'm finding out that my modded RE0 actually sounds very closed, muffled and dark compared to the GMP 450 Pro. The PX100 is simply incomparable, it just has a surprisingly natural tone...

Now I can't really find anything wrong with the sound, actually it's better than my initial expectations for this headphone.

My only issue with it now is that it's still a tad bright and the treble is still a little harsh on some "energic" recordings.

(But the treble harshness issue might not be the fault of the headphone itself, but instead, fault of my Yulong D100 which might not be giving an optimal amplification)

The midrange is really marvelous now, one of the things I like the most about this GMP 450 Pro.

Sound impressions of the three earpads I have will come with time.

For now I can say that the stock earpads sound warmer than the perforated round velour ones.

The round velour are a little brighter and make the sound even more open improving soundstage, there is slightly more clarity, bass is a little less strong but still very present and is tighter, better balance, I like these earpads the best now.

Haven't tried the oval perforated earpads yet.

Curiously it doesn't sound identical to the QP 400 which has the same perforated round velour earpads in stock form...

When I heard the QP 400 and 450 Pro head to head both seemed to have identical tonal accuracy/color and the QP 400 didn't display the same sonic advantage over the QP 450 Pro that I'm experiencing with the "open GMP 450 Pro vs closed GMP 450 Pro.

This leads me to conclude that both the GMP/QP 450 Pro and 400 enclosures degrade the sound quality of this transducer.

German Maestro has confirmed to launch a new top of the line headphone this year (by the summer I believe) and it will be based on the GMP 400 with a price point of more or less 2.5x the GMP 400. I wonder if I'm not hearing to it right now...

So it would be interesting to see this done to other MB Quart/German maestros 450 Pro, 400 or even 90X or 95X...

If anyone has any questions just shoot'em.

EDIT: made some information additions

Just forgot to say that the GMP 450 Pro can be put together as easily as it is demountable...

Just to comfort anyone thinking about doing this disassembling work...

Nice work!

This is certainly interesting - probably something I won't do to my CharterOak because the mentioned colorations from the enclosures aren't necessarily bothersome for me.  I feel closer to the music in the closed CharterOak vs. the open QP400.  I won't talk of this until myself and JGOelfke finish up the write up :)

You say German Maestro is releasing a new flagship??? Link?

Looks like my wallet might take another hit.

Also, according to CharterOak, the SP-1 was manufactured by MB Quart and not German Maestro.

you mentioned that you had not heard the same colorations with the QPs as you had with the GMPs.

Could've been the gear you had the QPs plugged into, but the GM guys possibly doing some tweaks could also be why I do not hear the colorations you are mentioning

Here is the link.

It isn't said that it will be based on the GMP 400, error of my memory, sorry!

It will be something new...

I perfectly understand that you don't want to open your Charteroak, if you're already happy with, that's all that matters.

And I certainly wouldn't open mine if it had a lifetime warranty! : )

Regarding my GMP 450 Pro I'm finding out that the open configuration doesn't sound necessarilly better than the closed configuration on all of my recordings.

The sonic diferences between both configurations aren't always the same, nor as pronounced on all my recordings.

On good recordings, though, the open configuration clearly wins and the difference is pretty dramatic.

I will need more time to come up with a comprehensive comparison between both configurations with the different earpads I have.

That should be my real contribution to Head-fi.

STOKITW?! Have you opened your GMP 450 Pro already?

Nice work.

I don't have the urge to make my GMP450 open though.

It has the niche to be a closed back phone in my lineup.

BTW, I don't prefer GMP400 over GMP450.
 

Quote:

Originally Posted by kkl10 

 

Here is the link.

It isn't said that it will be based on the GMP 400, error of my memory, sorry!

It will be something new...

 

I perfectly understand that you don't want to open your Charteroak, if you're already happy with, that's all that matters.

And I certainly wouldn't open mine if it had a lifetime warranty! : )

 

Regarding my GMP 450 Pro I'm finding out that the open configuration doesn't sound necessarilly better than the closed configuration on all of my recordings.

The sonic diferences between both configurations aren't always the same, nor as pronounced on all my recordings.

On good recordings, though, the open configuration clearly wins and the difference is pretty dramatic.

 

I will need more time to come up with a comprehensive comparison between both configurations with the different earpads I have.

That should be my real contribution to Head-fi.

 

STOKITW?! Have you opened your GMP 450 Pro already?

This work combined with our write up should really bring something to the table with the German Maestro/MB Quart phones.

It's stuff like this that makes the hobby so addicting!

JGOelfke is waiting on some equipment to show up before we do this.  A week or two out is my guess...

Quote:

Originally Posted by kkl10 

 

Here is the link.

It isn't said that it will be based on the GMP 400, error of my memory, sorry!

It will be something new...

 

I perfectly understand that you don't want to open your Charteroak, if you're already happy with, that's all that matters.

And I certainly wouldn't open mine if it had a lifetime warranty! : )

 

Regarding my GMP 450 Pro I'm finding out that the open configuration doesn't sound necessarilly better than the closed configuration on all of my recordings.

The sonic diferences between both configurations aren't always the same, nor as pronounced on all my recordings.

On good recordings, though, the open configuration clearly wins and the difference is pretty dramatic.

 

I will need more time to come up with a comprehensive comparison between both configurations with the different earpads I have.

That should be my real contribution to Head-fi.

 

STOKITW?! Have you opened your GMP 450 Pro already?

I'm loving the possibility of changing the GMP 450 Pro from closed to open and vice-versa.

In closed configuration the sound isn't as enjoyable musically but is very appropriate for studio purposes... in this regard the closed configuration is better than the open.

And forget about what I said about the enclosures degrading the sound!

It seems to me now that the enclosures were purposefully designed to tune the sound this way in order to better suit studio work... just what German Maestro claims to be the purpose of the GMP 450 Pro.

Watching a movie was what changed my mind about the enclosures.

So I might just be earing something very close to the GMP 400 equipped with the same earpads that I own.

I actually like the looks of it without enclosure, lol. I will just leave it that way...

And I also think that there is the possibility of improving isolation by filling the rectangular opening around the driver with some material... I think those opening are the reason of the poor isolation of the GMP 450 Pro in stock configuration.

Before I do my write-up I'm also contemplating the possibility of acquaring the Fischer Audio FA-003... it's getting my attention for some time and, at least, is another headphone to which compare.

It will take some weeks to report my complete findings.

Good stuff, should be a good time!

I'd agree with the bit about the intended use.  I definitely feel closer to the music with the closed SP-1 with a very detailed, lean, agile monitor feel to it.

We'll stay in touch.

Quote:

Originally Posted by kkl10 

 

I'm loving the possibility of changing the GMP 450 Pro from closed to open and vice-versa.

In closed configuration the sound isn't as enjoyable musically but is very appropriate for studio purposes... in this regard the closed configuration is better than the open.

 

And forget about what I said about the enclosures degrading the sound!

It seems to me now that the enclosures were purposefully designed to tune the sound this way in order to better suit studio work... just what German Maestro claims to be the purpose of the GMP 450 Pro.

Watching a movie was what changed my mind about the enclosures.

So I might just be earing something very close to the GMP 400 equipped with the same earpads that I own.

 

I actually like the looks of it without enclosure, lol. I will just leave it that way...

 

And I also think that there is the possibility of improving isolation by filling the rectangular opening around the driver with some material... I think those opening are the reason of the poor isolation of the GMP 450 Pro in stock configuration.

 

Before I do my write-up I'm also contemplating the possibility of acquaring the Fischer Audio FA-003... it's getting my attention for some time and, at least, is another headphone to which compare.

 

It will take some weeks to report my complete findings.