USING RESISTORS TO MATCH IMPEDANCE

[Macksamillion]

I don't know if this is crazy, or maybe people do it all the time. You guys can tell me. I have a Taramps DS4404. It's a 4-channel amp, rated at something like 65 watts per channel RMS. I want to run a pair of 6.5" mids on two channels, and FOUR tweeters on the remaining two channels (two tweeters per channel). It gets interesting because I want to have all four channels running at a 4-ohm load. That means I need to have 8-ohm tweeters, right? Simple enough. The problem comes in when trying to find 8-ohm tweeters that LOOK LIKE ones you'd have in a car. All the 8-ohm tweeters look like the typical circular or horn cabinet-mount tweeters you'd find in a home audio speaker enclosure. I very much want to have that look of a recessed swivel car audio tweeter.

Here's the question. is it acceptable (or practical) to wire a 4-ohm resistor in series with the voicecoil of a tweeter, in order to increase its impedance to 8-ohm? That way, I could wire each pair in parallel to achieve my desired 4-ohm load. Will this work? If it does work, is there a downside? Will it throw off something in the amplifier? Will it affect the sound quality of the tweeter?

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[Popwarhomie 5,000+ posts]

Not a good idea. Resistors add alot of heat and will you will lose alot of power using one as well as added distortion.


All that really comes to mind right now is Dayton AMT

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Dayton Audio AMT Mini-8 Air Motion Transformer Tweeter 8 OhmThe Dayton Audio AMT Mini-8 model features a round housing and compact AMT element, for wide dispersion that easily replaces dome tweeters in retrofit or new design applications. The AMT Mini-8 is small enough to be used in compact...

www.parts-express.com

But that amp is 2 ohm stable so just wire two tweeters on channel 3 and two on channel 4 at a 2 ohm load.

 

[Macksamillion]

I

Not a good idea. Resistors add alot of heat and will you will lose alot of power using one as well as added distortion.


All that really comes to mind right now is Dayton AMT

Home

Dayton Audio AMT Mini-8 Air Motion Transformer Tweeter 8 OhmThe Dayton Audio AMT Mini-8 model features a round housing and compact AMT element, for wide dispersion that easily replaces dome tweeters in retrofit or new design applications. The AMT Mini-8 is small enough to be used in compact...

www.parts-express.com

But that amp is 2 ohm stable so just wire two tweeters on channel 3 and two on channel 4 at a 2 ohm load.

I know it's stable at 2 ohm, but it's most efficient at 4.

 

[Popwarhomie 5,000+ posts]

I

I know it's stable at 2 ohm, but it's most efficient at 4.

30 amps before impedance rise that big of an issue with your setup?

 

[Macksamillion]

30 amps before impedance rise that big of an issue with your setup?

4-ohm per channel is paramount.

 

[dragon.breath 10+ year member]

If running 4 ohms is important to you, run 8 tweeters. 4 per channel.

I would just run two tweeters at 2 ohms per channel. The difference to the ear would be unnoticeable.

 

[Macksamillion]

If running 4 ohms is important to you, run 8 tweeters. 4 per channel.

I would just run two tweeters at 2 ohms per channel. The difference to the ear would be unnoticeable.

If running 4 ohms is important to you, run 8 tweeters. 4 per channel.

I would just run two tweeters at 2 ohms per channel. The difference to the ear would be unnoticeable.

I thought about running 8 tweeters. I just can't imagine how to integrate 8 tweeters into the landscape of the vehicle and still have it look stock.

 

[Popwarhomie 5,000+ posts]

4-ohm per channel is paramount.

So what is your end goal? You trying to run a tweeter per door in a 4 door? You running two mids and two tweeters per front door? Component sets out of the picture? Sound quality or just loud?

 

[jt4x4]

Electrically, it will work. Realistically, there are better ways to run the speakers you want. If you use resistors to create the load you want, you will use a lot more power than you need to. I would suggest wiring your speakers as desired and setting the gain very conservatively. Using resistors as you described will use more electricity to go to waste.

I would say "correct me if I'm wrong", but the regs on this forum do so without request.

Good luck.
- Joe

 

[trumpet 5,000+ posts]

The mistakes here are 1) assuming speakers behave like a resistive load. 2) assuming music has enough high frequency energy to result in power output to tweeters that will equal that of mids.

This is a non-issue. Run the tweeters you want. Your bigger concern is protecting the tweeters from damage. Use the appropriate high pass filter and install a non-polarized capacitor on each tweeter for a backup crossover.

To Cap or Not to Cap? Tweeters in Systems with Active Crosso...

Lets say you park your car on a hill. Let's also say it's a standard transmission, and you leave it in gear. It should be there when you return, right...

www.audiofrog.com

 

[Macksamillion]

So what is your end goal? You trying to run a tweeter per door in a 4 door? You running two mids and two tweeters per front door? Component sets out of the picture? Sound quality or just loud?

Theorhetically, I just wanted to know if this concept was possible. Realistically, I want to do SQ and I want to have as much control as possible, so I don't want to do components. I'd rather do a separate tweeter channel. One member responded with something that really made sense, so I think I might not worry so much about the impedance after all.

 

[Macksamillion]

The mistakes here are 1) assuming speakers behave like a resistive load. 2) assuming music has enough high frequency energy to result in power output to tweeters that will equal that of mids.

That makes sense. I never thought of it that way. Thanks.