[disappointed in R15M Speakers]

On 1/16/2016 at 3:50 PM, rybn said:

I was also disappointed with the frequency response. So I opened the back terminals unit and checked the crossover circuit electrical frequency response. What I found explains what the problem is. the crossover point is at 1800 Hz as specified BUT at that frequency both the bass and the twitter levels are at -11dB instead of -6dB.

The crossover schematic is shown in the attached file. The inductors values are not marked.

The only way that I could fix it without replacing the whole circuit, was by adding a 10uf  (2x22uF back to back connected) capacitor in parallel to the 3.6uF. This change shifted the crossover level to -7 dB but the crossover frequency moved to 1350 Hz.

Listening to the speakers now is so much better that I will keep this modification, unless the Klipsch company will see this post and provide a replacement crossover units.

Thank you for sharing your experience. I cannot find the attached file... 

 

Cheers!

[disappointed in R15M Speakers]

I also find the R-15M speakers with poor treble response, so I decided to understand/learn about its crossover circuit.

The crossover is of course passve and working with LC circuits in both drivers. It is a second order crossover, which is the best relation between loss and frequency response. It works at 1800Hz.

On the tweeter section, you´ll find out that it´s a RLC filter (it has a resistor) and placed to prevent tweeter damage and balance the sound.

According to my measurements, frequencies higher than 6KHz are slopping down the plot.

Technically the tweeter has much higher sensitivity than the woofer, so that is why there is a resistor to balance the sound (which is not working properly),

The solution is simple, but we don´t want to mess-up with the crossover frequency, which will unbalance soundstage (unless you design a new crossover i.e. 2400KHz).

Finally, just replace the 7.5ohm/10w resistor with a 1ohm/2W resistor and you´ll be amazed immediatlly with the real sound of these speakers.

Give it a try on one speaker and compare both channels working and same time.

You won´t regret for sure!

 

Happy new year!

Miguel