Reply to thread

Message

<blockquote data-quote="maylar" data-source="post: 1058276" data-attributes="member: 541144">All true, with caveats...1) Car audio is a bit unique.. 3 feet of 10 gage wire is not uncommon, and doesn&#039;t limit DF like long runs of speaker cable in a home system.2) Ported enclosures and IB aplications are where DF can be significant. In a sealed box, acoustic damping has much more effect.3) Some amps have output impedances in the milliohms. DF of 400 or more (Tru amps for example).However, there&#039;s the issue of &quot;specmanship&quot;. If the spec is calculated at 8 ohms, the DF figure would be twice the value of 4 ohms. It&#039;s a worthless spec unless the load impedance is also specified.In car audio we&#039;re more concerned with efficiency than power transfer. Effieciency goes up as the load impedance goes up or the source impedance goes down. A 1:1 ratio gives 50% theoretical efficiency. OK in communications circuits, not OK in amps.I agree with you that 100 is an acceptable number.</blockquote>

[QUOTE="maylar, post: 1058276, member: 541144"] All true, with caveats... 1) Car audio is a bit unique.. 3 feet of 10 gage wire is not uncommon, and doesn't limit DF like long runs of speaker cable in a home system. 2) Ported enclosures and IB aplications are where DF can be significant. In a sealed box, acoustic damping has much more effect. 3) Some amps have output impedances in the milliohms. DF of 400 or more (Tru amps for example). However, there's the issue of "specmanship". If the spec is calculated at 8 ohms, the DF figure would be twice the value of 4 ohms. It's a worthless spec unless the load impedance is also specified. In car audio we're more concerned with efficiency than power transfer. Effieciency goes up as the load impedance goes up or the source impedance goes down. A 1:1 ratio gives 50% theoretical efficiency. OK in communications circuits, not OK in amps. I agree with you that 100 is an acceptable number. [/QUOTE]

Verification