I have a problem with my pair of DB drive platinum PL12 D2, because i change my car for a hatchback and I do an enclosure with the specs. of db drive, (ported 3.5 ft3 for both) but it sound´s better in another car, I want to make an enclosure for deep deep bass but i don´t know the size of the box, I have about...7 cuFt in my hatch.

contact the maker direct. There is nothing online

https://dbdrive.net/contact/

https://www.google.com/search?q=DB+Drive+Platinum+PD300+amp+manual

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You could try these people. They may supply or repair it

https://fixmyspeaker.com/
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The vibration from the bass is cutting off the amp. it is a loose wire causing this issue. you can also get a stabilizer that will stop the vibrations from causing this issue.

db stands for Decibels. A unit for input sensitivity amps. Visit the site "Electro-help".

It is a term which need more clarification. Visit this site 'Electro-help'

Fo (Hz) : 29.581 QMS : 3.965 QES : .517 QTS : .457
VAS (liters) : 147.723 REVC (Parallel-Ohms) 1 SPL @ 1 watt/ 1 meter (dB) : 90.6 X-Max Linear peak-peak (mm) 70 LEVC @ 1kHz (mH) : 1.043 Enclosure Volume (Sealed) : minimum 2 cubic feet Fill Required % : 0 3dB down point (-3dB) : 43 maximum sealed: 2.5 cubic feet n fill required: 39 at 3 dB down point Enclosure Volume Ported Vented (cubic feet) : 5.0 Vented to Hz: 35 3dB down point (-3dB Hz) : 28 Square port area Sq/In : 80 Port Length : 13" Power Handling : 2000 Watt RMS & 4000 Watt Max. Make sure to use MDF for the enclosure and use 1 inch thickness and use braces as well. This is a beast of a sub woofer. So give it the proper power it needs and make sure that your box is very solid in construction. If installed correctly and given the right power, this sub woofer is bound to put a smile on your face and rattle your bones. I hit 142dB with only one of these subs and im sure if i gave it more power i could hit the 150dB range. DON'T FORGET TO GIVE IT THE POWER IT DESERVES. Have fun dreamsystems.

the common reference seen to be the problem ,ussually a burn copper track pcb from rca input also check transformers

Just get the model number off of the top of the amp and put it in a google search... like dbdrive1400.1amp and it will come up with specs and stuff for it..

TS-W307D2
Design and Specifications 12” Dual Voice Coil (DVC) Subwoofer for Enclosure applications 1,200 Watts Max. Power Handling 400 Watts Nominal Rating Qts = 0.44 Xmax = 8.7mm Fs = 33.9 Hz Vas = 42.2 litres Frequency Response : 18 ~ 500 Hz. Efficiency : 89 dB Impedance : 2 x 2 Ohm (Total 1 or 4 Ohms) Delivered with “jumper link”: ready for 4 Ohm use f0 (Lowest Resonant Frequency) : 33.9 Hz. Recommended Sealed Enclosure : 24 ~ 49.6 Litres RECOMMENDED sealed enclosure, not Ported. 24 Litres = 1464.569 cu. inches 49.6 Litres = 3026.777 cu. inches

The only real way of telling is a true bench test of the speakers. The speakers should be but on an amp with an adjustable tone generator at o db. The amp. should be hooked up to load resistors with 0 db(.775 milivolts) frequency sweeping hooked up to a ocilliscope to test properly. Anything else would be just a shot in the dark or a quess.