DiyMobileAudio.com Car Stereo Forum banner

1 - 6 of 6 Posts

·
Premium Member
Joined
·
55 Posts
Discussion Starter #1
Hi guys, I'm an old fart that used to be in to car audio in the early-mid 90's, and after finding out that most of the company's that I'm used to seeing as quality have pretty much gone to crap, I'm starting to question everything. So here's what I've got:

Alpine CDA-117 w/Imprint
Soundstream RUB 5.800
Morel Maximo front stage
Boston G2 10" sub

So I came across an old PPI 4200m for free and I was wondering if - even though the wattage is less - it would be better for the front stage. From what I've read, the "M" series is not bridgeable without an adapter, and I'm not going to go through the trouble of finding one as I'm sure they're extremely rare. I'd like to just run it in 4 channel mode going to the front and rear speakers, just like I have the Rubicon right now. I do like to listen to my music slightly louder than most 'normal' people, but I also like clean sound. I like hearing the fine details in the music, and from what I've heard, the Rubicon just can't deliver on those fronts. What's your input?

I also came across another old A/D/S PQ10. It has a sticker on the back that says that it's been repaired. What do I need to look for to make sure that it was repaired with quality components and that it was done correctly?

A little off topic, and I searched for the answer to this but couldn't find it: What is a shorting ring with regards to subwoofers?

One other thing - I'm a Tech Service Manager for one of the big 4 HVAC manufacturers, and having been in the field, I know that the quality wire is the solid wire (at least for that application). When I initially hooked up everything in my car, I used some old speaker wire from back in the day. Not thinking much of it, but knowing that it was probably too small to pass the wattage, I went and bought some very high quality speaker wire. Once I replaced it, it was a very noticeable difference in clarity. The sub is cleaner and tighter, the mids/highs are slightly more detailed, etc. The wire I pulled out was stranded, but the new wire that I got has a MUCH finer strand to it. What's the reasoning behind this? I mean these strands look thinner than a human hair almost. I know A/C voltage has a lot of power and DC is a cleaner type of power, but why is the good stuff so fine and the 'not so good' stuff a heavier strand with less of them?

Thanks for all of the help guys, I'm seriously enjoying being on this site. Having just gotten back in to car audio, I'm learning a lot and I'm paying attention to things that I never would have without this site. Thanks again!
 

·
Registered
Joined
·
156 Posts
Here's the skinny on the shorting rings (from NPDang, 2005)

Simply put, it can be used to lower distortion and/or inductance... when used properly. There's all kinds of implementations, including bad ones which actually worsen the driver's performance. The most popular one seems to be a ring on top of the pole piece, or in the case of the Seas Excel and Scan-Speak there's a ring both on top of the pole, as well as below. The most extreme cases use a full length copper sleeve over the pole piece, such as Lambda acoustics or the Adire Extremis.
 

·
Premium Member
Joined
·
55 Posts
Discussion Starter #4
Here's the skinny on the shorting rings (from NPDang, 2005)

Simply put, it can be used to lower distortion and/or inductance... when used properly. There's all kinds of implementations, including bad ones which actually worsen the driver's performance. The most popular one seems to be a ring on top of the pole piece, or in the case of the Seas Excel and Scan-Speak there's a ring both on top of the pole, as well as below. The most extreme cases use a full length copper sleeve over the pole piece, such as Lambda acoustics or the Adire Extremis.
OK, I'm with you on that one. But what does it actually do?
 

·
Registered
Joined
·
156 Posts
OK, I'm with you on that one. But what does it actually do?
Pulled from the HTGuide Forum:

Current flowing from the voice coil generates its own magnetic field. This goes through the pole piece and air gap. There is already a magnetic field in the air gap provided by the magnet. Net magnetic field inside the air gap then becomes the sum of the fields from magnet and voice coil current. But linear operation of the speaker requires the magnetic field inside air gap to be constant. (B of BL product, which when current flows on the voice coil, causes the voice coil to move by Lorents force) This causes distortion. Another thing related to this is that, the permeability of the pole piece and other parts of magnetic circuit of the speaker motor gets modulated by the field generated by the voice coil current, which means the inductance of the voice coil gets modulated by voice coil current. Voice coil inductance also is supposed to be constant (for a frequency) for linear operation of the driver. When it gets modulated by current, distortion occurs. The cause of both these distortions is the magnetic field generated by the voice coil current. A shorting ring, which is a single short circuit turn, can be considered as the secondary winding of a transformer that is short circuited. The primary winding is the voice coil. The voice coil current induces a current on the shorting ring, which always has a polarity that generates a magnetic field that opposes the field that induced it. This causes the net magnetic field generated by the voice coil current to reduce, and so BL modulation by current and inductance modulation by current gets reduced, and the distortions caused by these gets reduced.
 

·
Premium Member
Joined
·
55 Posts
Discussion Starter #6
Pulled from the HTGuide Forum:

Current flowing from the voice coil generates its own magnetic field. This goes through the pole piece and air gap. There is already a magnetic field in the air gap provided by the magnet. Net magnetic field inside the air gap then becomes the sum of the fields from magnet and voice coil current. But linear operation of the speaker requires the magnetic field inside air gap to be constant. (B of BL product, which when current flows on the voice coil, causes the voice coil to move by Lorents force) This causes distortion. Another thing related to this is that, the permeability of the pole piece and other parts of magnetic circuit of the speaker motor gets modulated by the field generated by the voice coil current, which means the inductance of the voice coil gets modulated by voice coil current. Voice coil inductance also is supposed to be constant (for a frequency) for linear operation of the driver. When it gets modulated by current, distortion occurs. The cause of both these distortions is the magnetic field generated by the voice coil current. A shorting ring, which is a single short circuit turn, can be considered as the secondary winding of a transformer that is short circuited. The primary winding is the voice coil. The voice coil current induces a current on the shorting ring, which always has a polarity that generates a magnetic field that opposes the field that induced it. This causes the net magnetic field generated by the voice coil current to reduce, and so BL modulation by current and inductance modulation by current gets reduced, and the distortions caused by these gets reduced.
Wow. That certainly explains it! Awesome explanation by the way.

So I'm guessing these are really on the super-high-end drivers?
 
1 - 6 of 6 Posts
Top