P-5 bass management


Bronze Member
Username: Diggytooth8

Post Number: 30
Registered: Sep-10
Hello again just purchased a Parsound P-5 pre-amp. I run a HT system through it as it has a bypass. I have (1) HSU VTF 3MK-4 sub I use for both HT and 2.1. The pre has variable high and low pass crossovers. I run my HT system as small using the AVR's crossover. I am having trouble wrapping my head around the bass management on the pre. I don't hear much low end from the pre when listening to 2.1, no matter how I set the crossovers. Should they alwyas be set to the same value? What is the best way to run the sub to the pre amp given the way I have it all hooked up? My mains are Klipsch RF 62's II. They apparently go down to 35 hz.

Platinum Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 17867
Registered: May-04

There is no one way is right to set up a system like yours. The only time the rules would apply would be in the instance of a THX system where ALL the rules of THX have been applied. Those systems are rare.

First, I doubt your Klipsch actually have useable bass response down to 35 Hz. The system may respond to a 35 Hz signal, but it will be significantly down in level from, say, 1kHz which is likely to be down in level, say, 100 Hz. That's the way Klipsch are built to operate.

The larger issue though is the room in which the system operates and the variable ups and downs - peaks and nulls - of the whole resonant system. It's virtually impossible to make any real differences in bass response within a domestic room beneath about 200Hz no matter what you've done with room treatments. Therefore, the frequency band where you want to set you crossovers is squarely in the middle of the most volatile bandwidth.

To make matters more complicated, you've not said what crossover order you have on each filter. If one filter on your processor has a second order filter and your sub has a fourth order filter, the two combined make for a roller coaster ride in the shared bandwidth.

Start with the idea you should be using one filter and not several. Set your sub's crossover to its highest crossover frequency and let the processor do the actually filtering. This is the general rule but may be the least desirable if the sub has the steeper filter action. A 24dB per octave filter is typically the better to use in preference to a 12dB filter. Since there are no standards for any of this in consumer audio, you have to make up some rules on your own based on the realities of your system.

Start though with your sub essentially out of the filtering business and set your processor's filters to do the work. You can set the frequency limits for the processor by ear or by measurement. There is no perfect answer again since there are no rules. Bass lumps and bumps created by the room and the speaker position within the room will give very different readings on a measurement base set up. There is no one right answer.

IMO, you'd do best to contact Parasound for their advice on how to best set up their processor.


Bronze Member
Username: Diggytooth8

Post Number: 31
Registered: Sep-10
Thanks a million Jan. After messing with it for hours and hours, I found the only way to get decent low end was to turn off the low and high pass crossovers and run full range to the mains. The pre still sends a signal to the sub, it is full range as well. If I turn on the subs crossover at that point, it sounds o.k. I believe now the mains and the sub are both producing the same range, but when I turn on the high pass and filter out some of the low end to the mains it just sounds tinny. I know room acoustics and sub placement are the issue here. No room to move anything around, small room.
Thanks again Jan.

Gold Member
Username: Magfan


Post Number: 3106
Registered: Oct-07
I have been looking into the P5 as a potential upgrade path for my system.

If it were ME in MY system, I know what I'd do�or at least my starting point.

Parssound P5 low pass crossover OFF. Turn the subs crossover ON and set to maybe 60 to 80 hz. Somewhere maybe 1 octave (70hz, in this case) ABOVE the LF cutoff of the 'main' speakers.

Turn the P5's HIGH PASS to ON and adjust for a frequency somewhat higher than the subs crossover frequency. This will not only EASE the burden on the main amp, but provide for a gentle transition between main speakers and sub.

The effect? As the subs output is diminishing as frequency RISES, the main speakers output will FALL as frequency decreases. ELECTRICALLY there will be a 'dip' in response, but the 2 speakers will SUM FLAT (audibly) thru the crossover region.

The Parasound manual lists crossover slopes at 12db / octave which will be shallower than the (probably) 24db / octave low pass crossover of the sub.

Once you are starting to make some 'progress' towards the desired setup, DO NOT forget the phase switch on the sub. Most are 0/180 but some are 'continuous'. In either case, adjust, while playing some bass heavy music, for most robust bass output.

As you are adjusting for bass level, don't be afraid to go too far�..than it's certainly fine to back off some.
The advice in the Parasound book which comes w/the preamp is fairly generic.

You MIGHT want to enlist the aid of a couple large friends. Take turns STANDING IN CORNERS and you will be able to perceive a change�.usually for the better� bass response at the desired listening position. Than you can replace the buds with some corner traps of which many are available and even can be DIY'D.

Bronze Member
Username: Diggytooth8

Post Number: 32
Registered: Sep-10
Good advice, thank you I will try it. Interesting about the corner traps. Will report back.
Thank you all

Gold Member
Username: Magfan


Post Number: 3174
Registered: Oct-07
I just had an idea. Probably, I'm too late, but here goes:

First, I bought a P5 and a pair of A23 power amps. Good Stuff.

I realize now that there is a front panel sub level control on the P5. Have you tried THAT?

Also, with your HT stuff set to 'small', does that IN ANY WAY mess with the output of preamp level TO the P5? What I'm thinking is that with the HT stuff set to 'small', you are cutting the LOWS from the output TO the P5�.and the sub?

Try setting the HT to 'large' just for an experiment.

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