Can I replace a 4 ohm speaker with a 4 ohm power resistor?

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SUMMARY

Replacing a 4 ohm speaker with a 4 ohm power resistor is feasible, particularly when connecting it across the tweeter terminals while using a speaker across the bass terminals. The discussion confirms that a passive filter, such as the two-way lowpass filter mentioned, does not significantly add resistance or rob power from the speaker. Adjusting tone controls on the amplifier, like the Tribit Stormbox, is a simpler alternative when available. The use of a resistor value close to 4 ohms, such as 3.9 ohms or 4.7 ohms, is acceptable for this application.

PREREQUISITES
  • Understanding of speaker impedance and resistance
  • Familiarity with passive filters in audio systems
  • Knowledge of amplifier tone controls and their functions
  • Basic electronics principles related to circuit connections
NEXT STEPS
  • Research the specifications and performance of the Tribit Stormbox amplifier
  • Learn about the design and function of two-way lowpass filters
  • Explore the impact of speaker impedance on audio performance
  • Investigate alternative methods for adjusting audio output without tone controls
USEFUL FOR

Audio engineers, DIY audio enthusiasts, and anyone looking to modify speaker systems or improve audio performance without tone controls.

pkc111
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TL;DR
I have a single speaker powered by an off the shelf rechargeable boom-box. The speaker is 4 ohm 10W and I want to take the treble out completely as I am going to use it to drive a Ruben's tube. I was thinking of using a 2 way lowpass passive filter from Amazon inline before the speaker. I have read that they only work if there are 2 speakers connected, so would it work if I placed a 4 ohm power resistor across the tweeter speaker terminals and just used my speaker across the bass terminals?
Also would a passive filter add much resistance to the circuit and rob the speaker of power?
Here is the 2 way lowpass filter I was thinking of. I don't need 2 of these obviously but they seem to come as a pair.
https://www.amazon.com.au/dp/B07R613YSK/
 
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so would it work if I placed a 4 ohm power resistor across the tweeter speaker terminals and just used my speaker across the bass terminals?
Yes, but usually not needed.
You could just not connect the Tweeter terminals at all. Or even short them if really needed.

Much easier/cheaper to adjust the tone controls on the amplifier.

Cheers,
Tom
 
pkc111 said:
I have read that they only work if there are 2 speakers connected, so would it work if I placed a 4 ohm power resistor across the tweeter speaker terminals and just used my speaker across the bass terminals?
Replace the tweeter with an approximately 4 ohm resistor. It is not critical, 3R9 or 4R7 would work OK.

pkc111 said:
Also would a passive filter add much resistance to the circuit and rob the speaker of power?
No. The losses in the filter are small.
 
Thank you so much!
I agree the tone adjustment on the amp would be easier.. but it doesn't have one. Its the Tribit Stormbox
https://www.tribit.com/products/Tribit-StormBox-Portable-Speaker-Black
 
Most likely this can only be answered by an "old timer". I am making measurements on an uA709 op amp (metal can). I would like to calculate the frequency rolloff curves (I can measure them). I assume the compensation is via the miller effect. To do the calculations I would need to know the gain of the transistors and the effective resistance seen at the compensation terminals, not including the values I put there. Anyone know those values?

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