Setup ADD

[olds1959special]

So, due my hifi ADHD I have changed my setup again, after getting everything perfect (again.) Ever heard the saying, put all your eggs in one basket? Well, I have four Kenwood LM-05’s, and was previously using one pair for my Elac DBR62’s and the other pair for my Vandersteen Model 2’s. I just decided to plug all four amps into the Vandies, knowing how power hungry they are. I think I’ll get some Topping B100’s for the Elacs later, but for now I’m focusing on enjoying my Vandersteen system. After installing the additional two amps (bi-wiring to lows and highs separately) I noticed an increase in “presence”, not necessarily loudness. I liked the change but felt like boosting the tweeter and midrange contour controls more after doing this (a feature of these speakers.) I put the subwoofers, set up in stereo, behind the speakers and flipped the phase to 180 to avoid a loss of some bass frequencies. The gain and LPF of the subwoofers has not changed. I’m slightly concerned about only 5” of vertical space above the amps for ventilation (google recommends 6” for amps of my specification), since they are in a semi-enclosed furniture unit, but I’m pretty sure these amps run relatively cool so I don’t think I should worry about it. Please let me know if I’m mistaken about this.

 

[DVDdoug]

bi-wiring to lows and highs separately) I noticed an increase in “presence”, not necessarily loudness.

If you aren't adjusting the high & low levels separately there shouldn't be any difference. But if you can adjust the levels separately that allows an additional "tweak" you can play with. But of course the speaker is designed to have the same signal into the high and low inputs.

I put the subwoofers, set up in stereo, behind the speakers and flipped the phase to 180 to avoid a loss of some bass frequencies.

Whatever works best. Some amps invert so it's possible that the main speakers are phase-reversed relative to the subwoofer. The position or orientation of the speakers & sub shouldn't matter that much unless they are far apart. Low-frequency soundwaves radiate in all directions, in the same phase.* The wavelength at 100Hz is about 10 feet, so if the main speakers are 5-feet closer to your ears than the main speakers, that's a half-wavelength and the soundwaves will be 180 degrees out-of-phase and cancel (if their SPL levels are identical).

If you have a proper crossover the phase is only important in the crossover range where the sub and mains are both operating.

I’m slightly concerned about only 5” of vertical space above the amps for ventilation (google recommends 6” for amps of my specification), since they are in a semi-enclosed furniture unit, but I’m pretty sure these amps run relatively cool so I don’t think I should worry about it.

I wouldn't worry if they don't feel hot. But will get a certain temperature rise, depending on how hard you drive them so it's more "dangerous" on a hot day. ...You could drill some ventilation holes under and behind the amps.



* That's assuming a "regular speaker", not a dipole or cardioid.

 

[olds1959special]

If you aren't adjusting the high & low levels separately there shouldn't be any difference. But if you can adjust the levels separately that allows an additional "tweak" you can play with. But of course the speaker is designed to have the same signal into the high and low inputs.


Whatever works best. Some amps invert so it's possible that the main speakers are phase-reversed relative to the subwoofer. The position or orientation of the speakers & sub shouldn't matter that much unless they are far apart. Low-frequency soundwaves radiate in all directions, in the same phase.* The wavelength at 100Hz is about 10 feet, so if the main speakers are 5-feet closer to your ears than the main speakers, that's a half-wavelength and the soundwaves will be 180 degrees out-of-phase and cancel (if their SPL levels are identical).

If you have a proper crossover the phase is only important in the crossover range where the sub and mains are both operating.


I wouldn't worry if they don't feel hot. But will get a certain temperature rise, depending on how hard you drive them so it's more "dangerous" on a hot day. ...You could drill some ventilation holes under and behind the amps.



* That's assuming a "regular speaker", not a dipole or cardioid.

Thanks! They tend to radiate a fair amount of heat when left on for a while, but it seems like they have enough ventilation regardless. I had previously lowered the shelf to get 6" of vertical room but had to reduce to 5" to fit all the amps in there.

 

[olds1959special]

I put my Harrison In line 50 hz hp filters on the amps powering the bass, and plugged in my Topping A70 Pro as a preamp, running balanced from my DAC. This is sounding good.

Edit: Changed to 70 Hz filters on lows / 80 Hz LPF for more clarity

 

[olds1959special]

About ventilation: I am putting four small usb powered fans behind the amps and I can turn them on with a switch behind the unit.

Using 100 Hz filters now on the lows.