Topic: RD's T50RP mod v0.5 (Read 6578 times)

rhythmdevils · « **Reply #20 on:** March 05, 2012, 10:43:21 PM »

Interesting. I was saying to add additional holes to the squares that already had holes in them and leave the other squares intact to remove treble and add bass. Hard to describe this in an email, but this is interesting too.

I'll have to do additional tweaking and send them back when I feel totally happy with them I had only finished the foundation for this mod the day before you picked them up, so there's a number of things to try still...

Marvey · « **Reply #21 on:** March 05, 2012, 10:47:31 PM »

I couldn't do what you asked because I just had to even out the FR. The diaphragm should have equal pressure at all parts, otherwise you get wierd standing waves.

rhythmdevils · « **Reply #22 on:** March 05, 2012, 10:50:46 PM »

Hmm I've had success with it, they gave it a fancy name- "differential damping" in the ortho thread. Are you sure about the standing waves?

It has to be done in the right way though, as damping different parts of the driver has different effects on the FR. I felt the corners of the T50rp driver needed the most damping.

LFF · « **Reply #23 on:** March 06, 2012, 12:27:40 AM »

Looks like a fantastic job!!!

When I saw the new graph I was like....

Good job to both you!

Marvey · « **Reply #24 on:** March 06, 2012, 01:01:08 AM »

Quote from: rhythmdevils on March 05, 2012, 10:50:46 PM

Hmm I've had success with it, they gave it a fancy name- "differential damping" in the ortho thread. Are you sure about the standing waves?

It has to be done in the right way though, as damping different parts of the driver has different effects on the FR. I felt the corners of the T50rp driver needed the most damping.

Well, "evening things out" did produce a more linear FR...

dBel84 · « **Reply #25 on:** March 06, 2012, 03:00:19 AM »

Greetings all. I guess it only appropriate that my first post be ortho related AND to give a heartfelt "well-done" to the 2 of you. I spent many hours playing with the T50RPmkII way back and felt I had achieved a relatively smooth response from about 100Hz up, but it rolled off pretty steeply below 100 and with the plethora of options, it just never found a place in routine use. It would be very interesting to see what it might have measured like.

To clarify differential damping - ( and wualt does not "approve" of the theory ) , with some of the center pinned drivers, the diaphragm does not present a uniform wave front and thus the idea is to "differentially" damp different 'radii' of the driver so as to achieve adequate damping without killing the bass. I think it might apply to some of the tensioned drivers too as some of them are pleated to allow for the opposite wave motion of a center pinned driver. ( picture a butterfly flapping its wings as opposed to a trampoline with someone bouncing on it) - this really needs animation as my analogy sux but hopefully you get the idea. One of the best examples of the latter is the LCD2v1, it is technically the best driver I have ever seen.

before I get distracted by many tangential thoughts, has anyone compared the FR plots of a well modded T50RPmkII to one of smeggies TP's ( recent ones as the original had room to improve )

congrats again ..dB

rhythmdevils · « **Reply #26 on:** March 06, 2012, 03:16:59 AM »

Quote from: purrin on March 06, 2012, 01:01:08 AM

Well, "evening things out" did produce a more linear FR...

We'd have to see a graph of the approach I was suggesting to compare.

I think the same thing (or similar) would have happened if you'd opened up more holes in the parts of the driver that already had some and left it "differentially damped". Too bad we don't have two pairs to compare. But this is interesting too, so no worries.

It's complicated, I tried a lot of different things but there's so many combinations. If you change something in the lining of the cups, then you have to go through and try all the different driver dampings again because one might work now that didn't before. It's like one of those books of different heads/bodies/legs that you can slide and combine in different ways. Of course you learn what different things sound like and get better at guessing. But earlier on, porting all parts of the driver resulted in resonances or FR love bumps in the upper midrange. However, I changed some things since then, so maybe it works now...

V1 will have no peaks!

I wish we lived closer! There's so many things I'd love to have measured to see how it compares to how I hear them.

rhythmdevils · « **Reply #27 on:** March 06, 2012, 03:18:03 AM »

Oh, and welcome Don! Nice to see you here. :-)

RexAeterna · « **Reply #28 on:** March 06, 2012, 08:31:51 AM »

that is very good work. so you guys figured out what works for back of the driver? what material was it originally? i remember looking at mine and seem like some type of white felt or type of fabric that felt similar to like dryer sheets(or whatever those things are. i can't believe i got a brain fart. i need some more caffeine in my system or something lol). anyone ever go to like a thrif shop and tried different materials or browsed around something like a home goods place or even home dept out of curiosity?

i glad there is a way though and you guys found it. the materials though is so odd but genius at the same time what you guys are doing. i only know basic stuff from messing around with speakers and my room in the past and as always use my imagination with drawing out stuff. i never thought of using other materials untill i found out bout rhythm's famous coffee filter mods cause i was like ''no freakin way. i must try it''.

EDIT: well i gotten bored and i fixed the channel imbalance below 50hz on my fostex on the right ear cup. i could of fixed them right away after i gotten them back from purrin but i was too excited to get my DF's back and was too lazy to open mine up anymore to be honest.

rhythmdevils · « **Reply #29 on:** March 20, 2012, 08:43:15 PM »

I'm pretty sure the stock cable is causing or at least contributing to, the 10k peak. Any way to check this Purrin by comparing stock cable to Vmoda cable?

If not, I'll send both cables next time :-)

Author Topic: RD's T50RP mod v0.5 (Read 6578 times)

rhythmdevils

Re: RD's T50RP mod v0.5

Marvey

Re: RD's T50RP mod v0.5

rhythmdevils

Re: RD's T50RP mod v0.5

LFF

Re: RD's T50RP mod v0.5

Marvey

Re: RD's T50RP mod v0.5

dBel84

Re: RD's T50RP mod v0.5

rhythmdevils

Re: RD's T50RP mod v0.5

rhythmdevils

Re: RD's T50RP mod v0.5

RexAeterna

Re: RD's T50RP mod v0.5

rhythmdevils

Re: RD's T50RP mod v0.5

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Author Topic: RD's T50RP mod v0.5 (Read 6578 times)