the12volt.com spacer
the12volt.com spacer
the12volt.com spacer
the12volt.com spacer
icon

Running One VC on a DVC Sub


Post ReplyPost New Topic
< Prev Topic Next Topic >
audiocableguy 
Copper - Posts: 630
Copper spacespace
Joined: January 27, 2003
Location: Idaho, United States
Posted: April 05, 2006 at 10:07 AM / IP Logged  
If you were to add a Pot to adjust Q what impedence would you use?
haemphyst 
Platinum - Posts: 5,052
Platinum spaceThis member has been recognized as an authority in Electrical Theory. Click here for more info.spaceThis member has been recognized as an authority in Mobile Audio and Video. Click here for more info.spacespace
Joined: January 19, 2003
Location: Michigan, Bouvet Island
Posted: April 05, 2006 at 4:29 PM / IP Logged  
I would use a 2 ohm to 16 ohm, 5 watt (or so), linear taper pot. (The resistance stated on any pot is the maximum resistance - so a 2 ohm pot, or a 16 ohm pot, or something between those values should be fine...)Probably wont HAVE to have a 5 watt power handling, but too small might burn out... I have never done any experiments to figure the actual power produced by a secondary voice coil. The lower the resistance the pot is, the more power it will need to be able to dissipate.
It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."
proatthagame 
Copper - Posts: 65
Copper spacespace
Joined: April 16, 2006
Location: United States
Posted: May 12, 2006 at 12:46 AM / IP Logged  

haemphyst wrote:
( ala this article, posted by Steven Kephart of Adire Audio)
[/QUOTE]

Insert from article above

What about driving just a single coil, and leaving the other open? Well, as you would guess, the push is weaker. The system has a peakier resonance (for the techie types, Qts increases because Qes increases). BUT - let's drive one coil, and short the other. Guess what? Things change from the original (both coils driven) situation, but they also stay the same. The driven voice coil is pushing and pulling, as normal. But what about the shorted voice coil? Well, it's trying to keep things at rest - it's trying to resist ANY motion! The net result is the overall peakiness of the resonance is the same as it was when both coils were driven, even though we are only using half the motor (driving one coil). The other coil helps "tame" the driven coil, so that the system basically behaves the same as before.

He mentions driving a single coil and leaving one open and driving a single coil and shorting the other. What is the difference between the two?

Yours Truly
DYohn 
Moderator - Posts: 10,735
Moderator spaceThis member has made a donation to the12volt.com. Click here for more info.spaceThis member has been recognized as an authority in Electrical Theory. Click here for more info.spaceThis member has been recognized as an authority in Mobile Audio and Video. Click here for more info.spacespace
Joined: April 22, 2003
Location: Arizona, United States
Posted: May 12, 2006 at 8:50 AM / IP Logged  

proatthagame wrote:
He mentions driving a single coil and leaving one open and driving a single coil and shorting the other. What is the difference between the two?

With non-driven coil shorted, Qts remains equal to listed specs with both coils driven.  With non-driven coil open, Qts changes.  In any case,  power handling capability is cut in half

Support the12volt.com
proatthagame 
Copper - Posts: 65
Copper spacespace
Joined: April 16, 2006
Location: United States
Posted: May 13, 2006 at 2:53 AM / IP Logged  
So how do you short a voie coil?
Yours Truly
Steven Kephart 
Platinum - Posts: 1,737
Platinum spaceThis member has been recognized as an authority in Mobile Audio and Video. Click here for more info.spaceThis member consistently provides reliable informationspace
Joined: November 06, 2003
Location: Oregon, United States
Posted: May 13, 2006 at 5:20 AM / IP Logged  

Acutally power handling isn't halved.  Here's a quote by Dan Wiggins on this topic:

"Lastly, power handling isn't compromised by a factor of 2; it's usually decreased 10-25%. The reason is that rarely are you current-limited by the gauge of the wire, and voice coils are wound concentrically so you still have the entire thermal mass working for you. Just that now all the power is dissipated in a single voice coil (typically two of four layers) so you may end up with an inert, non-conducting thermal mass insulating one side of the voice coil. This does not halve power handling, but can reduce it somewhat."

thrice010 
Member - Posts: 5
Member spacespace
Joined: May 10, 2006
Location: United States
Posted: May 18, 2006 at 12:53 AM / IP Logged  
DVC subs are great for different wiring options but why in the world would anyone power one VC.  IMO...get a 2 ohm stable amp.  Good topic tho
bmwpwner 
Copper - Posts: 174
Copper spacespace
Joined: January 28, 2006
Location: United States
Posted: May 18, 2006 at 10:45 PM / IP Logged  
good point but here is what you have to keep in mind. when you are selling equipment in a business type atmosphere you want to stock equipment that can be versatile enough to fit a bunch of different customer's needs. and it helps if you can show the customer that the equipment they are buying today will allow them to add to the system without having to get rid of the old equipment first. for example i usually mention that if they are getting 1 sub (maybe for a truck or something that has limited space) then they should choose a woofer with DVC and a slightly bigger amp so that they can later add another sub to the same amp if they move the system to a car or extended cab. then i explain that with the single woofer you can use one VC (4 ohms) and wire that into the bridged setting on the amplifier (mainly because everyone wants the amp in mono) and with 2 subs you can wire them into 8 ohms each and then mono that into the amp. this way they are always getting maximum performance out of the amp and the sub or subs. great solution and it so much easier to teach sales person which brand to sell versus having 4 or 5 different model number in each woofer line.
"I cannot teach anybody anything, I can only make them think."
-Socrates-
thrice010 
Member - Posts: 5
Member spacespace
Joined: May 10, 2006
Location: United States
Posted: May 19, 2006 at 9:00 PM / IP Logged  
i do agree in the business world, that may be brought up.  I can't say that I havent said that to a customer already but point being...its not the best route.  For people that do want to keep that amp because they dont have the money for another one...that may be just fine :)
couchflambeau 
Member - Posts: 3
Member spacespace
Joined: June 10, 2005
Location: United States
Posted: May 27, 2006 at 4:51 PM / IP Logged  

Are any of the other Thiel Small parameters affected by running only one of two coils?  Mainly concerned on how box calculations would be affected by running only one coil and if the published manufacturers recommended enclosure size would still be valid...?

Good topic, lots of snake oil going around about this....

Page of 16

  Printable version Printable version Post ReplyPost New Topic
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot delete your posts in this forum
You cannot edit your posts in this forum
You cannot create polls in this forum
You cannot vote in polls in this forum

  •  
Search the12volt.com
Follow the12volt.com Follow the12volt.com on Facebook
Thursday, January 21, 2021 • Copyright © 1999-2021 the12volt.com, All Rights Reserved Privacy Policy & Use of Cookies
Disclaimer: *All information on this site ( the12volt.com ) is provided "as is" without any warranty of any kind, either expressed or implied, including but not limited to fitness for a particular use. Any user assumes the entire risk as to the accuracy and use of this information. Please verify all wire colors and diagrams before applying any information.

Secured by Sectigo
the12volt.com spacer
the12volt.com spacer
the12volt.com spacer
Support the12volt.com
Top
the12volt.com spacer
the12volt.com spacer