I did no use a pot for testing. Our local brick and mortar electronics supply is closed due to moving to a new location and I did not want to buy a wire-wound pot online not being able to see it. If the wire turns are thick and not being able to peak inside the pot it might be hard to get the ohms where I want.
So, I home-made my own high-watt resistors using about 20 ft of 0.042 nichrome wire I had laying around combined with old guitar strings. Btw the E string 0.010 is a little over 8 ohms. I think this gave me very accurate resistors. The metal wire resistors I made did not get warm at all.
I am running the testing with one speaker cabinet xo with the Lpad and the other speaker without Lpad for comparison.
I used the diyaudio Lpad calculator. I did a 12 dB attenuation first. I wanted to start with a big attenuation to see what happened. Way too much attenuation even after adjusting the EQ to boost the HF and cut the LF. Plus the 211-parallel fuses in the xo were glowing the when trying to drive the LF sometimes very bright.
I then did a 6 dB attenuation and it sounded pretty good after adjusting my EQ to pretty close to 3dB boost overall on the LF and boosting the HF by about 6 dB. However the 211-parallel fuses in the xo were glowing to some extent more than the other speaker xo without the Lpad.
My next test (and likely my last test) will be at 3dB attenuation. I already know that will be the sweet spot for me. I just can't run the test until next week when my wife is gone.
What I question is: How much power is too much for the 211-parallel fuses in the xo?
How can I tell what is too much other than pushing them to burn out?
Is it OK to run the fuses bright enough to read a book? I have no clue on this.
I know you said 100 Watts probably not. I am trying to get a grip on that. I know the 3rd order Butterworth High Pass part of the xo limits the power by not allowing LF to the HF drivers. I get that. But the Eminence xo data states that the 211s start compressing at 250 watts. That part is confusing to me. The Lpad calculator shows that if I run 360 watts to the Lpad then the speaker will see 180 watts with the Lpad set for 3 dB attenuation. Does that mean that the remainder of the 360 watts is going to the LF drivers as well as heat coming out of the fuses? Or is the Lpad calculator showing a generic sort of power rating for a LF speaker like woofer? Thanks for helping me out.
This says that if you drive the tweeter using one higher frequency sine wave, enough to put 360W into 8 ohms then 180W will go to the Lpad and 180W to the tweeter.
However this is alot of power. It has been found that power in real music falls at near 6dB/oct. The peak is naturally below 1kHz.
If you use a 100W amp up to its limit, then a few octaves up you will be seeing only 1.5W total between the Lpad and tweeter.
I bet I have read this stuff before but it just takes hearing it again to sink in. What you said helps a lot to understand the power-to-frequency aspect.
I guess I should not worry about the fuses. The data states the compression from the fuses starts at 250 watts. Therefore I will assume the fuses can handle some degree of power that exceeds 250 watts. The Eminence xo is rated at 400 watt. The fuses are on the input side of the 3rd order Butterworth high pass envelope so whatever goes through the Lpad and HF speaker goes through the fuses. With my maximum possible output 360 Watt RMS at 8 ohms the fuses should never see enough to fry them as long as I don't do something accidental to cause that. I would say I will typically max the amp output to somewhere between 200 and 300 watts RMS per channel when connected to one 8 ohm cabinet per channel.
I assume that you read that I wired my guitar pickup out of phase in 2006. I now have the guitar wired correct and have done a lot of high volume testing with no indications of cutting out in the midrange like it did in 2006. So it looks like this speaker project is finally wrapping up with all indications of good sound quality. I don't think I will go the distance and test a full spectrum frequency response on these cabinets. These cabinets sound good now and I plan to play them for a while and then sell them along with some old Yorkshire Pulse 15s. I hope to take the funds from that and diy me a pair of huge 4 ohm 3way cabinets for 250 Watt RMS which is ultimately what I think will be best to run with my Peavey amp.
Thank you for your patience and help. I learned a lot.
