Rerurn to Romy the Cat's Site

jessie.dazzle wrote:

First question: With the 1.5 gallon rear chamber, the resonance is 700Hz With the basket sealed by tape (very small rear chamber), the resonance is 49Hz   Assuming there was not a typographical error, from this we can conclude:   1) Larger rear chamber volume = Higher resonance 2) Smaller rear chamber volume = Lower resonance 3) With the 5 small holes punched through the tape, effectively increasing the rear chamber volume, the resonance drops to 42Hz.   Only number 3 makes sense to me.   What am I missing?

Yes, to assume that I had no typographical errors was too big load to care. I have no idea where the 700Hz came from –we are light miles away from those frequencies. The numbers are following:

Vitavox 15/40 in open air – 50Hz
Vitavox 15/40 loaded in my horn with open back – 24.3Hz
Vitavox 15/40 loaded in my horn with 1.5 gallon back chamber – 24.7Hz
Vitavox 15/40 loaded in my horn with gasket sealed with tape– 49Hz
Vitavox 15/40 loaded in my horn with gasket sealed with tape and a few holed made – 42Hz

The rule no one changed:

 
1) Larger rear chamber volume = Lower resonance
2) Smaller rear chamber volume = Higher resonance

jessie.dazzle wrote:

Second question:   In the image showing the taped basket, the device on the top of the stack appears to be a frequency generator. If so, can you confirm that the signal is routed through, and amplified by the table radio? This would seem logical.   The reason I ask: I have always been afraid to rout a signal from the generator into either my pre-amp or directly to my power amps. Doing so would be very convenient, but I did not want to risk damage to the equipment, as the output voltage of the generator measures significantly more than a typical source component. Is there a safe way to rout a signal from this type of generator, directly into a pre-amp? If not, then into a power amp?

I am not sure why you worry. All generators have adjustable output. I use very cheap generator and even it has a gain control. I usually output around 1V. Depending of amplification of your power amp. BTW, to measure Fs if your generator has powerful output then you can drive a driver from it directly. You will not be able to measure current but you will be fine to measure voltage as generators usually have about 50R output impedance. I do not like to drive directly from a generator as generator might be direct coupled and run small DC in output - it might be not good for Alnico drivers. So, I use a small cheap amp…. Presuming that it has no DC in output….

Rerurn to Romy the Cat's Site