Low bass in music - Sub or no Sub ?

[vijwilso]

Hello experts

After reading this thread , I played test tones from 20hz . I could hear the bass starting from 30hz tone. However the published spec states speakers produce 60hz to 20000 hz. How is that possible . am I testing it wrong !!!?

 

[Thad E Ginathom]

Whilst it is safer to assume that speaker specs from the manufacturers are going to be kind to the marketing dept, it still doesn't mean that the quoted numbers have a sharp cut off. Specs with a +/- dB statement are more realistic, but still not that easy for us non experts to "visualise" (what's the aural equivalent?)

There is also another phenomenon, which I certainly cannot explain, and have only recently heard of. It seems that, given a number of of harmonics, our brains can produce the fundamental note, even though we are not physically hearing it. Somebody else might be able to explain this (please?): I'm not even sure what to google for .

 

[Nikhil]

Hello experts

After reading this thread , I played test tones from 20hz . I could hear the bass starting from 30hz tone. However the published spec states speakers produce 60hz to 20000 hz. How is that possible . am I testing it wrong !!!?

Nothing wrong with your ears. It's your room that is helping/boosting the LF.
Room modes will vary for different rooms.

Plug your room info into this online tool and you might get some insight:
http://www.hunecke.de/en/calculators/room-eigenmodes.html

 

[vijwilso]

What i tried is not a frequency sweep test . I downloaded several small mp3 files for every frequency for 20 , 30 , 40 and 60 hz . So i know it clearly that it plays just that frequency .

And speaker could play the tones from 30 hz in any position in the room

I downloaded the tones from here - http://www.testsounds.com/

 

[jls001]

60 Hz rated means it will play 60 Hz and above flat. Meaning it will reproduce 60 and up at full power. But all signals below 60 Hz will not be able to play with the same level (amplitude). The amplitude will roll off by a certain number of dBs per octave, say 3 or 6 dB/octave (or sometimes even higher). So in our example one octave below 60 Hz is a halving of 60 Hz = 30 Hz. If your speakers have 6 dB roll off per octave, 30 Hz will play exactly 6 dB lower amplitude than it did 60 Hz. Incidentally, human ear will perceive 6 dB lower to be about half the loudness. So if you play 30 and 60 Hz tones one after the other at the same volume setting, you will feel 30 Hz is about half as loud (actually it will be louder than "half" as room gain will boost bass freqs) as the 60 Hz tone.

Just because your speakers are rated at 60 Hz does not mean it will sharply cut off lower frequency signals. This of course assumes that the spec is 60 Hz 0 dB and not some shady spec like -3 dB at 60 Hz.

 

[manoj.p]

Hello experts

After reading this thread , I played test tones from 20hz . I could hear the bass starting from 30hz tone. However the published spec states speakers produce 60hz to 20000 hz. How is that possible . am I testing it wrong !!!?

The speaker rating shows the -3db point. So, that means the speaker will do 60 hz at -3db of its rated output. Below 60 db, the speaker will be still producing bass, albeit at lower output than rated.

Couple that rated output with some room gain and you can have quite output there. Also, its easy to hear this lower output when we are playing individual frequencies and nothing else is playing. However, when you play music like orchestra, these frequencies output will be quite low compared to others and you won't be able to distinctly hear these frequencies. Those other frequencies will mask it. Reverse of this happens when you turn up the subwoofer. All you will hear is boom boom and the other frequencies will be masked even though these are playing.

 

[Shivam]

Like I had said earlier, what mattered to me was what I could hear and what I could not. In my room at the volume that I listen to, I could barely hear the low frequency test tones from the Denon testing CD. This is in addition to the missing perspective of church organs playing Bach on my system.

I don't say that the speakers will not play test tones below what I could hear. but with some reduction in dB. My room is very good acoustically and standing waves produced combined with the speaker and listening seat placement also do not help the bass reinforcement.

I have got the REL T7 sub today. It matches very well with the rest of the system. I tried with the Denon test CD again and now I can hear frequencies upto around 30-40 Hz with no decrease in loudness. I will try some lower frequencies too. I am able to feel a lot of low end too which REL says that I should be able too. I tried the Bach organworks too and heard the grandeur of the organ at Methuen. There is some bass bloom which I think will have to be handled with proper placing of the sub. I am planning to use the usual 'interchanging of the listener and sub position' method, crawl around and find a good starting point for the sub.

Once the sub is ideally positioned, crossover and gain set and done a few hours of playing, I'll post my listening impressions too.

 

[Shivam]

REL T7 is a beautiful looking sub. The one I have got is in black piano finish and it is by far the best glossy finish that I have come across. The front has a passive radiator covered by a black cloth grill and the main driver is down-firing. The sub itself is supported by four solid aluminum feet. The top of the sub has a REL logo in aluminum embedded in the center. The overall look of black and silver matches well with my speaker stands (from magma) and thankfully my wife approves of the sub's looks. In terms of looks, my only complaint is the bright blue lamp on the back which I am planning to darken with a black marker.

 

[arj]

In terms of looks, my only complaint is the bright blue lamp on the back which I am planning to darken with a black marker.

try putting a dark insulation tape over it. you can put a pinprick if you still want to see the light
With RELs (unlike others) the corner works best for audio as well and their instructions are usually the ideal way.

 

[Shivam]

I feel that now I have found my audio nirvana.
AP active system was already doing a very good job and now with the low end extension provided by REL, it has become all the more refined and complete.

I have done many hours over the last two days with the REL and found a good placement too. The cross over is set to about 50 Hz so as to get a flat response all over. The gain is set at very minimal, It is just enough to make me enjoy the low level extension without feeling the presence of the sub.

For placement, I tried both the old and new REL recommendations first. One recommendation says to place the sub close to one of the speakers with the subwoofer driver (or passive radiator) at the same distance from the listening position as the drivers of the main speakers. This did not give me a very good response. I felt the lack of low notes. Next I moved the subwoofer to a corner. The corner placement gave me lot of presence in the low end but the notes were not well defined. Later after a lot of crawling around and experimenting, I found a good location near the wall behind one of the speakers, away from the corners.

I have been trying various genres of music and totally enjoying everything. Something which audio gurus have been saying for long but I have recently realized is that - without the low frequencies the music is very enjoyable but with the low frequencies one fails to understand how one could enjoy music for such a long time without those notes.

The church organs sound huge. I tried Martha Argerich's renderings of some of the famous classical works and found the Piano to be very realistic. Cowboy junkies' Trinity sessions also had the rumble of the airconditioners.
I tried some hindi songs next. Kishore Kumar live at Los Angeles had slightly more low frequency content than required and was overpowering the rest of the music. I had to reduce the subwoofer gain for this particular album. Shut Up and Bounce from Dostana had a nice foot tapping mid-bass without excessive thump or bloom.

 

[hydra]

Congrats, Shivam! It's always great when things fall into place and lock in perfectly with each other!

Do post pics! I'm very interested to see the placement.

You've taken the speaker level inputs (High Level Input) into the sub, haven't you? Did you feel that this has affected the signal sent to the speakers in any way?

 

[Shivam]

Congrats, Shivam! It's always great when things fall into place and lock in perfectly with each other!

Do post pics! I'm very interested to see the placement.

You've taken the speaker level inputs (High Level Input) into the sub, haven't you? Did you feel that this has affected the signal sent to the speakers in any way?

I'll try to post the pics sometime soon.

Yes, I did take the high level inputs into the sub. I was initially worried that this might reduce the levels of mid-bass and midrange being sent to the speakers but thankfully it didn't happen. As a layman, my guess is that REL takes a miniscule amount of voltage or watt (if those are the right words) from the main speakers which does not cause any audible change.

 

[Thad E Ginathom]

I feel that now I have found my audio nirvana.
AP active system was already doing a very good job and now with the low end extension provided by REL, it has become all the more refined and complete.

Wow.

I'm not sure that many stereo music lovers really take subs seriously, even if they have modestly-sized bookshelf speakers. I don't think that I ever have. Obviously, that is a mistake. Your post is the best reason I've ever seen to adopt a sub for classical/serious music listening

Congratulations on good conclusion to this. From problem through ideas and solution to implementation has been a real success. :clapping:

 

[prem]

Hi Shivam

Try reducing the crossover a bit and increase the vol a little. The dynamics should improve.

 

[arj]

Shivam, the way rel works, put the crossover at the 10db point of the speaker and as prem said increase the volume. The dynamics and the midrange will improve. You have a higher probability of getting this right in the corner. The way rels are built, with a higher crossover the sub is also playing into the midrange of the speaker . (Not sure of the newer rels..that's how the older ones did anyway !)

 

[Shivam]

I tried with test tones and a sound meter.
From midrange to 32Hz : Reasonably flat response. Two 3dB peaks at 47Hz and 65Hz.
32-27Hz -3dB
27-21Hz Sharp decline in loudness
Below 21Hz : soundmeter registered nothing.

I tested with the high frequency drivers disconnected.

On listening tests, I am still getting some bass bloom in some of the music albums / tracks. I will have to experiment more with the subwoofer placement, crossover and gain.

 

[Shivam]

I was talking to a friend of mine who raised two concerns about my setup.

1. The bass notes may differ in their timings in the two channels / there can be phase difference in the two channels in the bass region. Using a single sub cancels these out and so the bass response gets altered.

2. Single sub will make one person feel that there is a single sub and knowing its position will shift the soundstage by playing with psychology. It is better to have two subs to overcome this feeling.

How much of truth is there in these two points ?

 

[thampi]

useing one sub might affect the stereo imaging of the music.one for each channel is ideal

 

[Thad E Ginathom]

Beware the mights and maybes! I suspect that this is one situation in which throwing theory at the thing is not necessary: if it sounds good, it is good.

Psychology is very much on our side when it comes to experiencing and enjoying the stereo illusion. Let it alone and will do its job nicely!

 

[manoj.p]

I was talking to a friend of mine who raised two concerns about my setup.

1. The bass notes may differ in their timings in the two channels / there can be phase difference in the two channels in the bass region. Using a single sub cancels these out and so the bass response gets altered.

2. Single sub will make one person feel that there is a single sub and knowing its position will shift the soundstage by playing with psychology. It is better to have two subs to overcome this feeling.

How much of truth is there in these two points ?

1. Phase shift will depend upon where the sub is with respect to front speakers. You need to make sure that the sub is in phase with your stereo speakers. Play a test tone at cross over frequency and verify it.

2. Sound below 80 Hz does not localize, none can point out where the sound is coming from. If you have set crossover at 80, the only other thing that make a subwoofer presence felt is the level compared to speakers. Make sure its level matched.

If you take care of these two - and the subs are level + phase matched with fronts, the blending in is quite seamless. In that situation, listener would be hard pressed to tell when the speaker rolls off and sub takes over. On the other hand, if the sub level is hot (its easy to get carried away and run subs louder), then that masks off the higher notes from the speaker.