54L Sealed DPL12 Test Results (1 Viewer)

[Kyle Richardson]

If you bought it recently then its probably not the boosted version but its worth it to open it up to see what resistors are in the amp to make certain they didnt send the wrong one by chance.

Also, can you take a picture of the spider and tinsel leads?

BTW, it would be best to have the DPL12 side firing becuase of the soft suspension.

 

[Geoff L]

Brian/Kyle

Dose anyone know if the instructions that come with the current un-boosted version (300-794),,,,,,,, in fact make "Mention of the Boost"????

Seems odd to me that they make mention of it in Peters instruction manual! I have not purchased any PE-250's sence the dual model choice change over.
I have only purchased Rythmik's amps as of the last year or so.

I would have thought only the 796 would make mention of a boost in the instructions. Obviously sence that model carrys the it.

Regards
Geoff

 

[Brian Bunge]

I think the instructions for both amps are basically identical but I have not looked at them in a while. Most of the subs I've built in the last few months have used higher excursion drivers and I too have been buying rythmik amps.

 

[Peter DeWitt]

Dose anyone know if the instructions that come with the current un-boosted version (300-794),,,,,,,, in fact make "Mention of the Boost"????

What it say's is that if you want the boost change resistors R26 and R27 to x ohms. The resistor values change with the amount of boost you want. This is on an attached sheet.

I did order this recently, about 1 week ago.

Kyle-

I will take a picture this afternoon and send it to you. Would you like it posted here or e-mailed to you. If you haven't checked, I did e-mail you with a description of the problem and about a DC offset question about the driver.

 

[Peter DeWitt]

Well, curiosity got the best of me. The resistors are 56K and 120K, these are the values for a non boost model.

 

[Kyle Richardson]

Peter, post the pic here so we can collectively take a look and try to solve the problem.

When I watch the cone move as I inch up the volume, there is a point where the cone moves substantially from one position to another closer to the driver. It reminds me of a DC offset. This movement is about ½ or more of the Xmax. I would guess that it is moving at least ¼”. Like I said, maybe this is normal but it seams a little strange.

Did it do this when tested in the enclosure or free air? Normally the excursion should increase gradually with the increase in the gain knob and it shouldnt jump substantially with just a minute adjustment in the gain control. My only explanation for this is that it is the point where the driver starts to unload (no air pressure to control the driver if done freeair) or a defective amplifier.

Also, if you are doing all of these tests with the driver in a horizontal position switch it to vertical to see if it performs the same.

 

[Peter DeWitt]

I tested it in free air in both vertical and horizontal positions. The “abnormal” displacement happens in both the box and in free air. Obviously, the free air was more pronounced, but it was still very apparent in the box. At 20-25Hz, the displacement seemed relatively normal. However, when 30-40Hz was played, the displacement was large wrt the gain knob increase.

I am going to check the amp with a scope this afternoon and check for a DC offset. If it’s not there I don’t know what to think.

 

[Peter DeWitt]

Here are links to pictures of the leads.

Sorry I can't imbed them, the forum won't let me yet. Just ad http:

Non Rattling Side
//claymore.engineer.gvsu.edu/~dewittp/Non_Rattling_Side1.jpg

Rattling Side
//claymore.engineer.gvsu.edu/~dewittp/Rattling_lead1.jpg

//claymore.engineer.gvsu.edu/~dewittp/Rattling_lead2.jpg

Can I just bend the staycon tabs to make it more taught.

 

[Ronnie Ferrell]

imbeded photos:

Non Rattling Side


Rattling Side



Can I just bent the staycon tabs to make it more taught.

That's better!

rf

 

[Ronnie Ferrell]

What about a little bit of polyfil under the tinsel leads? (I have no idea if it would help. Just tossing it out.)

rf

 

[Kyle Richardson]

Peter, YGM

 

[Peter DeWitt]

I think getting lost in all of this was my first line in the initial post:

The results were encouraging and frustrating.

The encouraging part was that the DPL12 did an excellent job of reproducing the frequencies all the way down to 20Hz. The data I got was excellent and I do not want you to think I am expecting more from it. I cannot emphasize enough that this driver does things my 8” ported never could. It is excellent in this enclosure and I look forward to trying it in an 85L vented arrangement.

My only question was that it did not “perform” as I expected at the bottom end. In other words, the driver bottomed out at 30-35Hz but not at 20Hz. Perhaps what is happening is that I cannot send enough power to the driver @ 20Hz, or is it possible the “rumble” feature in the amp is kicking in?

At any rate, please do not think that I am dissatisfied with the DPL12. I just had some strange happenings that I was having trouble explaining and thought HTF would help me find the underlying cause of this mystery. You have all been great and I will try bending the staycon post and checking for the rattle again.

Again, when I calibrated the sub, it set up in the correct range and reproduced movie and music with a very tight and powerful sound. This phenomenon only occurred when I tried to push the sub and find its limits.

As I stated earlier thank you all for your help and maybe we can end this confusion with a K.I.S.S. solution.

RF-

Thank you for posting the pictures