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Post by PinkFloyd on Aug 14, 2007 8:58:27 GMT
Graham Slee? That name rings a bell
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mrarroyo
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Post by mrarroyo on Oct 27, 2007 21:39:50 GMT
If you go to the last post on the 1st page of this thread you will see I have modded the RP21 by removing the stock foam in front of the driver and by replacing the pleather pads w/ the velour pads from Beyer. I also installed the foam that Beyer supplies w/ their velour pads to protect the driver. If you read the referenced post you will see the results of the first two mods. Well today I had some free time in my hands and I decided to see what was inside the enclosures. I found it! Just plain air. It occurred to me that if I fill the space w/ cotton it might help to tighten the bass and remove a bit of the Boom Boom that I notice on some songs. I went to the medicine cabinet and took out some cotton balls as well as two round pieces of cotton applicators (make up stuff the wife uses ). After removing the ear pads and armed w/ an old phillips screwdriver I proceeded to remove the three screws which hold the drivers from the rest of the enclosure. I cut an slit on the round cotton to make sure it cleared the cable which supplies the "juice" to the driver. Quite thin, the cable is. Perhaps later I should re-cable this can. Although the RP21 looks huge it does not have a lot of space inside, therefore after installing the round cotton I was only able to squeeze one and a half cotton balls per side. The following thumbnails illustrate the sequence (remember to click on each if you want to see the full size picture). Going from memory I can say that adding the cotton has indeed removed any traces of Boom Boom. It appears that it has also removed too much of the bass. I will listen to it for the next week or so and then I may remove the round cotton to see if some of the bass returns. A friend has an un-modded unit and I will use it as a reference to judge the modification.
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Post by merton on Oct 27, 2007 22:08:47 GMT
yeah.... there has to be some room there for the bass to be.... you just need to line the walls with some thin foam or something to keep the bass from bouncing so badly. to stuff them full will destory the sound. that chamber is there for a reason.
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rowuk
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Post by rowuk on Oct 28, 2007 14:07:21 GMT
2 things happen when we add damping material to a closed box. The first is that the soundwave is damped, the second is that the enclosure increases acoustically in size (the speed of sound in damping material is different than in free air). With speakers we can "save" up to 20% volume by critically damping the box. Miguels "overstuffing" took the bump out of the bass, but probably extended it too, albeit at a reduced level. For headphones, it is impossible to keep the bass from bouncing, the volume of the can is simply too small. What we can do is reduce the effect that the reflection has - primarily in the upper bass and midrange. I have discovered that the QUANTITY of bass can be easily regulated by the thickness of the ear cushions. The closer the diaphragm is to the ear, the more bass. There was another thread on a Sennheiser 200 or 250 being damped successfully with bitumen weather stripping. - maybe something of interest here?
As far as Oldman and PF/Sandy/Miguel concerned, internet forums are a continuous lesson in the power of words. It never ceases to amaze me how the human state can turn things anonymous into personal. The forum members that have been here a while know what to expect/ignore. Somebody new I guess, should stay in the "ignore" mode until they get a "feel" for the characters involved. Oldman, I can assure you that there are SOME CHARACTERS here! Give us a chance, it CAN work! We appreciate your input! We just have problems with what seems to be ad text.
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mrarroyo
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Post by mrarroyo on Oct 28, 2007 21:02:42 GMT
rowuk, I am a troublemaker in a good sense. You are right, perhaps I and others could tone it down so newcomers do not get the wrong impression.
With regards to the cotton mod on the RP21's I can tell you that although the Boom Boom is gone the bass is still there. I will probably remove a bit of the cotton next weekend, after I have lived w/ the cans for a week to get used to its new sound signature.
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Deleted
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Post by Deleted on Oct 28, 2007 21:26:13 GMT
Rowuk You will have seen that I apologised a couple of times. However the reviews did read like advertisements,in two different forums, under 2 different names, and I am still puzzled by the quote below. SandyK
"When I wrote this I was not a 'distributor" for Mr. Slee, "
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Post by fanboi on Oct 28, 2007 22:27:53 GMT
"In fact I wrote an early review of the Solo posted on Head-Fi under my username Dandi. You will find it written in the same style as my Equation review. When I wrote this I was not a 'distributor" for Mr. Slee"
Looks to me that he is drawing attention to his writing style by giving another example where he was/is not a product distributor as had been alleged in respect of the HP subject of this topic.
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Deleted
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Post by Deleted on Oct 29, 2007 0:52:08 GMT
Tony I can see that now, but at the time it made me wonder more, as it seemed unlikely that there would be another "Mr. Slee" associated with the Equation Company. It isn't illegal, but I wish that people wouldn't post identical reviews in 2 different forums under completely different names.I did enough research before posting , to find that "dandi" post, but obviously I was too quick to jump to a conclusion. BTW, it was pretty recently, that as a moderator I deleted a full page commercial advertisement by a new Rock Grotto member. This time I made 100% sure of my facts. The same person had been banned by PC Tablet forum a couple of days earlier. You live and learn, hopefully not making the same mistakes along the way. Regards Alex
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rowuk
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Post by rowuk on Oct 29, 2007 10:57:52 GMT
I don't think apologies are absolutely necessary (although they do show the generally cooperative attitude here).
I think we just need a BIG warning like on every pack of cigarettes at the top of the entire forum: "The administrator has established that entering this site can be hazardous to your ego." And at the bottom - equally large: "BULLSHIT KILLS"!
I read those "reports" as ads or at least very "biased" too. I am still too new so I have not left the "ignore" mode yet.
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mrarroyo
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Post by mrarroyo on Nov 22, 2007 14:02:23 GMT
yeah.... there has to be some room there for the bass to be.... you just need to line the walls with some thin foam or something to keep the bass from bouncing so badly. to stuff them full will destory the sound. that chamber is there for a reason. Today I opened up the RP21 and took out the 1 and 1/2 cotton balls I had placed in each or the left and right chambers. I left the round cotton applicator on each chamber. Following this "de-cottoning" some of the bass is back w/o being boomy or overpowering, also the mids seem to be a bit more predominant w/ a bit more air to it. Oveall I am very happy w/ the "newer" sound.
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Post by cardude on Nov 24, 2007 14:26:43 GMT
Miguel,
How do you think these compare with the Goldring DR150s? I've been considering something new that's value priced. Thanks.
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mrarroyo
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Post by mrarroyo on Nov 24, 2007 16:08:01 GMT
Miguel, How do you think these compare with the Goldring DR150s? I've been considering something new that's value priced. Thanks. I no longer have my DR150. However they are different beasts in that the DR150 is an open can versus the closed design of the RP21. I will say that if you buy them used you could end up w/ two fantastic cans at about $200. I may put my RP21 w/ the Beyer velour pads for sale shortly.
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allenf
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Post by allenf on Jun 5, 2008 19:41:16 GMT
Based on how I remembered the RP21s to sound, I dissed them quite comprehensively over in Merton's DT770 thread here: rockgrotto.proboards39.com/index.cgi?board=review&action=display&thread=2880&page=2a) The RP21s are really not very good and sound cheap with a very dry top end and an echoey quality basically; Ouch ;D Having finally tried them with the V2 - and recalling that they have got less than 20 hours on them (duh!) - I stand by a less extreme criticism of the same points above. I have some self-adhesive felt left over from a pending Alessandro mod which I used on the RP21s to try and reduce the echoey plastic honkiness: Does it work? Oh yes indeed, there is still a small hint of top-end chalkiness but the echoey mid colouration is now almost completely absent. The felt steals very little volume from the chambers, bass is present, correct and tight. Bloody hell! For a couple of pennies worth of felt - well I never I have some Canare Starquad arriving in a few days; I'll convert these to dual entry with a recable and post an update. And I better burn them in while I'm at it
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