Any easy inexpensive way to high pass mains?

[jhollander]

PCD has a line level calculator in the additional circuit calculators tab

[Millstonemike]

PCD has a line level calculator in the additional circuit calculators tab

A couple of notes ... as shown in the pic of the calculator, you want C2 to be one tenth of C1 lest the second stage impacts the first stage of the 2nd order HP. And you don't need R2', you can just use the impedance of the amp.

The problem with FMODs is they don't specify the impedance assumed for the amp. Hence I assume they are using low values for Rs and Cs so that the amp's impedance has minimal impact on the advertised XO point. And that may be a strain on the signal stage driving the PLLXO - you don't know without values.

Earlier in the thread Chris mentioned a adding the HP to the Quarks passive XO. I had thought that was a good idea as they become "universal" independent of the feed. You could always add a switch to enable/disable the HP portion of the added components.

And, of course, the Voxel feed has come from before the PLLXO implementation.

[ksneote]

Is there an easy way to measure the impedance of an amplifier? I checked the specs, and no where did it mention that unfortunately.

Chris's high pass seemed too, well, high. I was under the impression that one should cross a subwoofer at 80hz and below, as the sound is harder to localize at those frequencies.

[Millstonemike]

Is there an easy way to measure the impedance of an amplifier? I checked the specs, and no where did it mention that unfortunately.

Chris's high pass seemed too, well, high. I was under the impression that one should cross a subwoofer at 80hz and below, as the sound is harder to localize at those frequencies.

I looked at the amp. The only way to use a PLLXO is with analog inputs. That amp only has one analog input, the 3.5mm Aux input. So if you plan on using any of the digital inputs your back to Chris with a passive high pass in the Quarks.

And the spec.'s for the amp's woofer LP filter are 200 hz, 24 dB per octave. It seems to be fixed so your stuck crossing higher.

[ksneote]

I looked at the amp. The only way to use a PLLXO is with analog inputs. That amp only has one analog input, the 3.5mm Aux input. So if you plan on using any of the digital inputs your back to Chris with a passive high pass in the Quarks.

And the spec.'s for the amp's woofer LP filter are 200 hz, 24 dB per octave. It seems to be fixed so your stuck crossing higher.

Ah right, I nearly forgot about that. I couldn't use the built in DAC. I'd probably purchase another SMSL amp without a built in DAC.

I was planning on using the subs plate amp as a LP. Would there be any issue with having a plate amp LP and the amplifiers built in one? As I'll probably have the sub LP set to a lower frequency

[Millstonemike]

I was planning on using the subs plate amp as a LP. Would there be any issue with having a plate amp LP and the amplifiers built in one? As I'll probably have the sub LP set to a lower frequency

Really depends on each system's LP. Not your case, but as one example ...

Take a plate amp with an 80 hz 12 dB LP fed with an AVR LFE output. The LFE LP output is set to 300 Hz 24 dB LP and the plate amp would just cut everything above the filter's 80 Hz corner freq.

At the other extreme, a plate amp with an 80 Hz 6 dB per octave Butterworth LP (Q=.707) and a feed with another 80 hz 6 dB per octave Butterworth LP will yield an 80 Hz 12 dB Linkwitz-Riley (Q=.5) LP filter - cut starts a little earlier with a gentler slope than a 80 Hz 12 dB Butterworth LP.

[ksneote]

Wanted to give an update on my attempt to find some sort of high pass. As per a Psycoacoustics suggestion, I actually managed to find a Velodyne CHT-8 subwoofer for $30. While searching Parts Express I came across some new Tang Band amps, with built in high pass/low passes/subwoofer amps. Funny that I found the perfect solution right after I bought my sub haha.

https://www.parts-express.com/tang-band-kit0058-2-x-5-watt-full-range-speaker-module-amplifier-with-bluetooth--264-966

https://www.parts-express.com/tang-band-kit0060-1-x-30-watt-subwoofer-module-amplifier--264-970

https://www.parts-express.com/tang-band-kit0059-2-x-10-watt-full-range-speaker-module-amplifier-with-bluetooth--264-968