25 replies to this topic

[simplesq]

Rare177, on Nov 27 2009, 11:46 AM, said:

i never knew it was possible to wire a single coiled 6ohm driver to 4ohms?

or are you referring to the rated power?

Tweeter Specifications:
Nominal Impedance: 6ohm
Power Handling: 200W

Amp Specifications:
2ch: 150 x 2 @ 4 ohms
4ch Bridged: 150 x 2 @ 3-8 ohms (6ohm at 30.0V)

[simplesq]

BMWTurbo, on Nov 27 2009, 11:56 AM, said:

You cannot change the speakers impedence. It's fixed (for this purpose anyways).
Yes Sir, I'm fully aware of this and had no intentention to.

Running a 2 channel amp that can supply 100WRMS into 4ohms, will give you roughly 75WRMS into a 6ohm load.
So the only difference would be a few drops in db.

Running a 4 channel amp that can bridge to 100WRM into a 4ohm load will give you roughly 75WRMS into a 6ohm load also.

Thanks for the replies...

[~thematt~]

Having a different impedance will just mean you get less then the rated power. You cant change impedance without passive crossovers.

[BMWTurbo]

simplesq, on Nov 27 2009, 10:29 AM, said:

Tweeter Specifications:
Nominal Impedance: 6ohm
Power Handling: 200W

Amp Specifications:
2ch: 150 x 2 @ 4 ohms
4ch Bridged: 150 x 2 @ 3-8 ohms (6ohm at 30.0V)

If they are the amp specs and the tweeters you will be driving :-

2 channel, roughly 112.5WRMS
4 channel, roughly 150WRMS

Roughly 1.5 dB difference between them in output into a 6 ohm load.

[jas]

so you are looking at a piccalo supremo morel 6ohm tweeter running on a 300/2 or bridged 300/4 jlaudio amp???

anyway i would look into the cheaper option 2 x100watts rms active is a hell of a lot of power for a tweeter. 300/2 would be easier to wire (no bridging RCAs) and just neater setup. WHy spend $100 more for power you will not require.

[simplesq]

Agreed 1.5db is not worth $150, I'll be picking up my 300/2v2 on Tuesday. The 2ch will also allow a direct connection for my silver coated directional RCA's & negate the need for y-splits. Thanks for the help Gentlemen.

[Cyberpunky]

You wouldn't need y splits with that 4ch amp to bridge it.

You can always run higher imp speakers off amps, its when you go below minimum its a prob. The spec doesn't mean its going to be better with 6 ohm than the 2 ch and infact bridging will decrease DF although as mentioned whether thats audible is another matter. All you would be doing buy getting 4 ch is getting more power period and as its to drive tweeters its definately not needed. Even with a claimed 200w rating you just don't need that sort of power to get them loud even if they were horribly inefficient. A 300/2 is overkill for tweeters anyway IMO.

<<< decides to bite tongue about silver coated directional RCAs lol

peace
Cyberpunky

[simplesq]

Cyberpunky, on Dec 4 2009, 01:06 AM, said:

<<< decides to bite tongue about silver coated directional RCAs lol

peace
Cyberpunky

No, please don't do that Cyberpunky. I am on the forum to be educated and appreciate any feedback...

[Luke352]

There is nothing for Bruce to bite his tongue about. I think Bruce was going to go on about Snake Oil products etc..

But there is nothing Snake Oil'ish about silver coated directional RCA's

The Silver coated copper helps prevent Oxidisation a useful thing to have, and the Directional is really a by product of the extra shielding process. Most RCA's just use the shield as the earth or as a totally seperate shielding, a directional RCA normally has a positive wire an earth wire and then the shield is actually connected to the earth wire at ONE end this acheives a much higher level of shielding as the shield works as a drain. Now this shield/drain works best when attached to the source end, hence directional.

[Cyberpunky]

Richard Clark and David Navone have done extensive testing to prove shielding has no benefit in a 12V dc environment. The shield is great in a 240/110V AC environment but can act as an antenna for noise in a car. Attach the *drain* wire makes this even worse as now the shield is connected to the chassis and has a direct conection to the noise source.

Unshielded twisted pair (UTP) has been shown to be the most effective as it uses the principle of *common mode noise rejection* that basically means as noise will enter each wire equally and the signal is out of phase, so the noise will cancel out.

In my experience noise entering via RCAs is extremely rare and tends to enter via components like HUs or amps, so IMO its a moot point anyway. The bottom line is though that many ppl still believe in using home audio theory in car audio and its doesn't always carry over. Shielding is a case in point. Great in Home or pro AC situations but useless in our 12V DC situation..

Yes silver will stop oxidisation but I have never seen a rusted RCA yet. Directional is of no benefit but as RCA induced noise is so rare anway it *probably* won't matter.

What another person thinks

I have used all types of leads and now use cheap mtx utp leads in my system that cost about $30 rrp each(about 6 pairs), except where the leads go into my amps and could be seen. for these I used $150 PG triple shielded leads caused I liked the connectors matching all my other PG gear

peace
Cyberpunky

Edited by Cyberpunky, 04 December 2009 - 02:12 PM.

[Pulse-R]

hey CP.. you do need Y-Splitters to bridge a 300/4.

otherwise it sounds bad and gets hot