Denon crossover settings not working properly? Mains are outputting 20 Hz content although crossover is at 250 Hz

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Isak Öhrlund

Junior Audioholic
Hi,

I have an issue with my Denon AVR-X4500H. If I set the crossover for my speakers to 250 Hz, and play a 20 Hz sine wave tone (using REW via HDMI), the mains should not be outputting any bass, right? Well, they are, along with the subwoofers, and I can't figure out why.

All speakers are set to small, LFE is set to LFE (not LFE + mains), the crossover is set to 250 Hz both in the general and the 2 CH settings. The sound mode is Stereo by default, and I've tried Pure direct as well.

I am running the receiver in a 7.1.4 mode, with an external amplifier for the mains. Latest update installed as of the 5th of April 2020.

Can someone help me understand whether I have misunderstood something, whether I am doing something wrong, or whether this is actually a bug?

Ps. The reason I tried this is because I want to align and EQ my two subs and don't want the mains to output any bass and screw up my results, and I don't want the bass signal that is supposed to go to the subs to get clipped because of the crossover settings, as suggested in this tutorial:
 
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I

Isak Öhrlund

Junior Audioholic
Yes, but from from 250 down to 20 Hz, is that reasonable?
 
P

PENG

Audioholic Slumlord
Yes, but from from 250 down to 20 Hz, is that reasonable?
It doesn't sound reasonable but not impossible as it depends on other factors such as harmonics distortions and room gain, among other things. Can you post your REW FR plots?

I don't have one for 250 Hz XO, but here's one for 110 Hz and you can see there is audible response at down to 20 Hz from the little LS50.

LS50_XO110Hz_Audyssey On vs Off.jpg
 
P

PENG

Audioholic Slumlord
By the way, if you use the App to run Audyssey and then do some manual tweaking after, you don't have to spend a lot of time trying to do anything else. Audssey+App+manual tweaking will get you very good results, and you don't like what Audssey does for the frequency above the transition frequency you can limit the range to 250 Hz or lower.
 
lovinthehd

lovinthehd

Seriously, I have no life.
You could also just disconnect the speakers while you setup the subs....
 
P

PENG

Audioholic Slumlord
Hi,

I have an issue with my Denon AVR-X4500H. If I set the crossover for my speakers to 250 Hz, and play a 20 Hz sine wave tone (using REW via HDMI), the mains should not be outputting any bass, right? Well, they are, along with the subwoofers, and I can't figure out why.
Again, you already know it isn't a brick wall so your speakers will have output even when fed with that 20 Hz signal, but how low/loud the level is, depends on your speakers, placement, and room, among other things. Since the subwoofer is running, it is hard to know how much you heard was from the speakers, it may be possible what you heard was mainly from the subwoofer. That's why it is good to plot some FR graphs using REW, for one of the (left or right) speaker on its own, and the subwoofer on its own. Or at the minimum, turn the subwoofer off, just to make sure how much output you are really getting from the speakers. You can check it with a sound level meter for dB output, and you will know if it would even sound like 20 Hz, or just harmonics.

As far as timing aligning the sub, Audyssey XT32 Sub EQ can do such a good job that it will be hard to beat doing it manually. I have spent countless hours to do things manually and the results were not as good as XT32 Sub EQ, not even close..
 
I

Isak Öhrlund

Junior Audioholic
Thank you all. I just did not expect the mains to output any sound at all at 20 Hz with a 250 Hz crossover engaged, so I wanted to know whether they should or not. I have not measured the response yet, because I was unsure whether the crossover was working properly when I heard that the mains were outputting sound and wanted to find out before I spent hours setting up my subs with my new miniDSP.

Also, I did not know whether disconnecting the mains would solve the issue, because I wanted to make sure that the subs are getting the full signal, so that they don't start to roll off earlier than they should (considering that the mains were outputting sound that I thought they should not).
 
P

PENG

Audioholic Slumlord
Also, I did not know whether disconnecting the mains would solve the issue, because I wanted to make sure that the subs are getting the full signal, so that they don't start to roll off earlier than they should (considering that the mains were outputting sound that I thought they should not).
Yes, HD is right, it would "solve the issue" if your concern is about the mains were making sound. The fact is, if you set the bass setting to LFE+Main, the subs will get everything the Mains would get, i.e. "Full signal".

I don't understand what you are trying to achieve though. It doesn't seem like you have an issue, but just in case, you can always do a processor reset.

1586178422214.png
 
P

PENG

Audioholic Slumlord
Thank you all. I just did not expect the mains to output any sound at all at 20 Hz with a 250 Hz crossover engaged, so I wanted to know whether they should or not.
As I said before, yes you will get some output depending on your speaker's in room response, but it should be very low, much lower than you would get at lower crossover points obviously.

I asked you in post#7 if you have made sure you were actually hearing the 20 Hz output from the mains only and not the subwoofer. You did not response, but it is an important point. 20 Hz is very non directional so if you did not turn off the sub one way or another, you may be hearing the 20 Hz sound mostly from the subwoofer(s) and very little from the mains.

Since I have time, I just plotted curves for various XO, the output drops off accordingly as expected.
 
I

Isak Öhrlund

Junior Audioholic
I just put my ear next to the mains, they're playing for sure. I'm about to EQ my two subs using a miniDSP, and when doing so, the mains must be silent, otherwise the miniDSP will be fed a response curve which it will try to, but cannot, correct.

Thanks for all the advice!
 
KEW

KEW

Audioholic Overlord
I just put my ear next to the mains, they're playing for sure. I'm about to EQ my two subs using a miniDSP, and when doing so, the mains must be silent, otherwise the miniDSP will be fed a response curve which it will try to, but cannot, correct.

Thanks for all the advice!
For frequencies as low as 20Hz, I would not trust my ears even if you are right at the speaker. If you hear upper harmonics or even the sounds from the attack of the note (which are almost always at higher frequencies) your brain will place the 20Hz at the source of those sounds!
 
lovinthehd

lovinthehd

Seriously, I have no life.
Other than disconnecting them you could just tell the avr they aren't connected. But I imagine its possible you could hear something thru the speakers since a crossover is not a brick wall.
 
P

PENG

Audioholic Slumlord
Other than disconnecting them you could just tell the avr they aren't connected. But I imagine its possible you could hear something thru the speakers since a crossover is not a brick wall.
He has the AVR-X4500H if I am not mistaken. As soon as you set mains to small, the sub will be selected to 1 by default automatically. Disconnect/or just flip the power switch if there is one, is the sure way if not the only way, but apparently he didn't want to bother trying..

I am quite sure he's hearing the 20 Hz mainly from the subwoofer and partially (just very softly) from the mains due to the non brick wall but 12 dB/Octave characteristics. That's if he set the volume high enough, if at -5 or lower, he shouldn't be hearing much of the 20 Hz, may be just like mosquito buzz.
 
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lovinthehd

lovinthehd

Seriously, I have no life.
He has the AVR-X4500H if I am not mistaken. As soon as you set mains to small, the sub will be selected to 1 by default automatically. Disconnect is the sure way if not the only way, but apparently he didn't want to bother trying..

I am quite sure he's hearing the 20 Hz mainly from the subwoofer and partially (just very softly) from the mains due to the non brick wall but 12 dB/Octave characteristics. That's if he set the volume high enough, if at -75 or lower, he shouldn't be hearing much of the 20 Hz, may be just like mosquito buzz.
I was thinking more of setting mains to off than small to start. Agreed otherwise.
 
Pogre

Pogre

Audioholic Warlord
Why a 250 hz crossover? That seems really high to start with. Are you using small cube-type speakers or something?
 
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PENG

Audioholic Slumlord
Yes, most do. How would that eliminate the mains, tho?
No I meant eliminate the sub. I suspect he's hearing the 20 Hz from the sub, the ear to grille is not a sure way as 20 Hz is pretty much completely non directional. Remember he's concerned the mains are producing 20 hz at XO 250 because of some bug.

He wants to make sure all the bass signals go to the subs for his manual time alignment. I trying telling him Audssey's sub EQ HT can do the job nicely, likely better as it will deal with.
 
Pogre

Pogre

Audioholic Warlord
He wants to make sure all the bass signals go to the subs for his manual time alignment. I trying telling him Audssey's sub EQ HT can do the job nicely, likely better as it will deal with
Yes, agreed. Audyssey's sub eq does a really good job with that in my experience.
 

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