LPF filter integrated Amp

[James240]

Hello all up untill now been using a 2.0 setup for Music/TV which consists of CXA81 integrated amp and a pair of Klipsch RP 6000 it's currently connected through Toslink to my TV.

I acquired a sub today a polk DSW 550i and connected it with a single RCA cable from the amp sub out to the LFE input of the subwoofer and put the LPF on the sub to max 120hz.

And well it sounds much worse than before lol it sounds like I'm getting a double bass booming effect from the towers and the sub fearing I did something wrong I removed the sub.

Did a bit more research and noticed people are saying the CXA81 doesn't have bass management?

 

[Vincent Kars]

The RO 6000 is specked as 38-25kHz +/- 3dB.
Obvious if you add a sub and set the crossover at 120, the whole 38-120 part is doubled resulting in that much beloved bass heavy car stereo sound.
If your speakers go down to 38 Hz, I wonder if you really need a sub.
If your speakers go down to 38 Hz, set the sub to 40 kHz or lower.

 

[Chrispy]

Sounds like you need a hpf for the speakers, i.e. an actual crossover for the sub/speakers (some subs can provide that with an actual crossover instead of the typical low pass filter labeled crossover). In the meantime maybe use the low pass filter control on the sub at a lower point to decrease the range of duplication.

 

[James240]

Thankyou so much for your replies i was a bit shy asking for help first.

Indeed the sub has binding posts which at first confused the heck out of me.

 

[Chrispy]

Thankyou so much for your replies i was a bit shy asking for help first.

Indeed the sub has binding posts which at first confused the heck out of me.

Even though the sub has high level (i.e. speaker level) inputs, doesn't change anything except getting full range as do the speaker terminals; possibly your sub pre-out has an upper limit fixed (didn't look). The main use of such is older 2ch gear without a sub pre-out.

 

[kemmler3D]

I looked up the manual for this sub and it looks like the LFE input/option bypasses the lowpass filter, so that's probably contributing to your problem. I think you just need to flip the LFE switch to "no". I would also turn the lowpass filter to something like 50ish hz and see where that gets you. You will also need to adjust the volume so it matches your mains.

And, welcome to ASR!

 

[James240]

I looked up the manual for this sub and it looks like the LFE input/option bypasses the lowpass filter, so that's probably contributing to your problem. I think you just need to flip the LFE switch to "no". I would also turn the lowpass filter to something like 50ish hz and see where that gets you. You will also need to adjust the volume so it matches your mains.

And, welcome to ASR!

Kemmler thankyou so much mate it seems that solved the issue! i always had the switch to on because it made sense as i connected it to the LFE port integrated amps sure are more fussy than AVR haha

While i have your attention do you think its worth adding room correction for a 2.1 system? i was looking at the Dirac PC suite that is on special atm

 

[AnalogSteph]

If you do not have bass management elsewhere, you will need some form of measurement + EQ facilities to get the frequency response in line. Basically, you would balance bass output between main speakers and sub with sub level and then reduce bass output to a sensible level.

 

[James240]

If you do not have bass management elsewhere, you will need some form of measurement + EQ facilities to get the frequency response in line. Basically, you would balance bass output between main speakers and sub with sub level and then reduce bass output to a sensible level.

Oh thats probably beyond my scope at this stage mate thats the thing about the CXA81 some say it does Bass Management others say it doesnt so i dont really know but my issue is solved so i cant thankyou all enough.

 

[er|κzvio1in]

Oh thats probably beyond my scope at this stage mate thats the thing about the CXA81 some say it does Bass Management others say it doesnt so i dont really know but my issue is solved so i cant thankyou all enough.

As a future option that most people here would highly recommend is to check out the addition of a MiniDSP which you can use to split the signal between amp & speakers and subwoofer. I've a CXA80 with 2 subwoofers and use a MiniDSP for 3 things: (1) crossover: HPF for speakers, LPF for subs, (2) time alignment for optimal integration of subwoofers, (3) parametric EQs to improve the bass response below the Schroeder frequency

 

[kemmler3D]

While i have your attention do you think its worth adding room correction for a 2.1 system? i was looking at the Dirac PC suite that is on special atm

Yes, 1000%, SO WORTH IT.

I don't use Dirac but I use REW to generate EQ for EQAPO (windows app.) It's really absolute night-and-day. Audiophiles say that all the time, but in this case it's real. Definitely get room correction in there if you can. There are many ways to skin the cat (@er|κzvio1in mentions MiniDSP which is also popular) but however you do it, it's almost mandatory IMO.

 

[Chrispy]

Oh thats probably beyond my scope at this stage mate thats the thing about the CXA81 some say it does Bass Management others say it doesnt so i dont really know but my issue is solved so i cant thankyou all enough.

FWIW. no, the CXA81 doesn't appear to have bass management per a look thru the manual. It has a sub pre-out, but that's not bass management.

 

[James240]

FWIW. no, the CXA81 doesn't appear to have bass management per a look thru the manual. It has a sub pre-out, but that's not bass management.

Thats what i thought thankyou all by far the most helpful audio community for someone with so many questions like myself.

I did not realise the depth of it the minidsp option and dirac live looks incredible but how on earth would i connect it to my CXA81.

I already have a complex setup with a PC to OLED with HDMI and Toslink out to a CXA81

 

[er|κzvio1in]

Thats what i thought thankyou all by far the most helpful audio community for someone with so many questions like myself.

I did not realise the depth of it the minidsp option and dirac live looks incredible but how on earth would i connect it to my CXA81.

I already have a complex setup with a PC to OLED with HDMI and Toslink out to a CXA81

It's simple: get a MiniDSP device that sits in between your OLED and CXA81, I'm doing exactly that. I use the MiniDSP NanoDigi 2x8 for that, but it's discontinued and I found a used one, that's your most cost effective option. From the current offering of MiniDSP you'd be looking at the 2x4 HD which has Toslink input and analog outputs. https://www.minidsp.com/products/minidsp-in-a-box/minidsp-2x4-hd A more fancy option would be the MiniDSP flex https://www.minidsp.com/products/minidsp-in-a-box/flex

 

[Earl Grey]

The RO 6000 is specked as 38-25kHz +/- 3dB.
Obvious if you add a sub and set the crossover at 120, the whole 38-120 part is doubled resulting in that much beloved bass heavy car stereo sound.
If your speakers go down to 38 Hz, I wonder if you really need a sub.
If your speakers go down to 38 Hz, set the sub to 40 kHz or lower.

This is interesting -- in one sense, yes, if your mains do 38 Hz you're reproducing all but the last octave already. But if you're trying to reduce the load on your mains it would still be useful. And if you're trying to do a multi-sub type approach to improve the evenness of response in the modal region, you might want not only a high-pass for the mains but a shelf, so that the mains can serve as two sources of the low-end as you add others with subs. It does seem weird to me that stereo amps almost never offer either of these, just a mono-summed sub out while full range goes to the mains.