Home Theater Forum and Systems banner
1 - 20 of 20 Posts

·
Registered
Joined
·
3,069 Posts
Discussion Starter · #1 ·
Hi there,

I have been playing with various curves to get deep bass and good mid bass punch but am not sure if I am going in the right direction. I have a flat curve, a hard knee house curve and a third curve which is like a house curve but with lower mid bass raised slightly.

I was wondering what kind of curve gets you punch in the chest bass. I am aware that it does depend on the sub but I think my dual 18" sealed should cover that area easily but I still feel I could do with more.

I know it is trial and error but it would be good to get an idea on what is a good starting point.

I am open to suggestions.

cheers

Graham
 

·
Super Moderator
Joined
·
9,302 Posts

I was wondering what kind of curve gets you punch in the chest bass.
Pose that question on the pro audio forums and they’ll tell you ~80 Hz. Keep in mind, that “punch in the chest” thing is largely dependent on the movement of air. In a high performance PA system that’s not hard to do since they have huge subwoofers, often lots of them, so it might not be fully attainable in a home system. If high performance car audio systems are what you're used to, the same applies: They have an exceedingly large number of subs compared to the size of the listening space. Still, I’d say 80-100 Hz is a good place to start.

Regards,
Wayne
 

·
Registered
Joined
·
3,069 Posts
Discussion Starter · #3 ·

·
Premium Member
Joined
·
15,054 Posts
My personal experience is not to raise your crossover, Leave it at 80hz boosting the 50-80Hz area will give you the best "Punch". Raising the crossover with start giving you localisation issues with the sub.
I've done both live concert mixing and studio and the punch starts in the mid 40Hz range up to about 80Hz going higher it will start to sound muddy.
 

·
Premium Member
Joined
·
15,054 Posts
It would be nice to boost the dip between 50 and 60Hz that will give you a very noticeable improvement. Do you have one or two subs? you may need to play with the phase on one or both of them.
 

·
Registered
Joined
·
3,069 Posts
Discussion Starter · #7 ·
tony,

One big sub. The blue dotted lines are what I have applied to in order to smooth and get rid of the dip between 50 and 60hz.

My thread:

http://www.hometheatershack.com/forums/diy-subwoofers-sealed-ported/21098-new-diy-sub.html


I don't have a phase on my sub as it is running through a behringer 4000 amp to my onkyo 876 via the BFD. I have two 18" FI Q18's in a 11 cu ft box (with stuffing). Very heavy, weighs 320lbs. :yikes:

Let me know your thoughts.

cheers

Graham
 

·
Registered
Joined
·
3,069 Posts
Discussion Starter · #8 ·
Right I just took some measurements from some test tones I put on to a dvdr as a data disc and have come up with some wierd findings. These are from the listening position which is about 2.5 metres away. Just the sub connected and here goes.

10hz - 67db
15hz - 78db
20hz - 82db
25hz - 78db
30hz - 79db
35hz - 82db
40hz - 87db
45hz - 93db
50hz - 99db
55hz - 102db
60hz - 99db
65hz - 99db
70hz - 102db
75hz - 92db
80hz - 85db
90hz - 79db
100hz - 78db

This was at volume -28db on the onkyo. Now for the really wierd thing my measured EQ graph in measuring flat but my readings are not. So is REW wrong as it is showing a massive peak between 45 and 75hz.
The other thing is why am I still hearing tones above 80hz. My crossover on the onkyo is set to 80hz.

cheers

Graham
 

·
Premium Member
Joined
·
15,054 Posts
Did you have the mic for REW in the same spot as the SPL meter? Different spots in the room will have different peaks and dips. Even moving the mic a foot can make a difference. This is why alot of people like to use two subs in different parts of the room to smooth out the response.
 

·
Registered
Joined
·
3,069 Posts
Discussion Starter · #10 ·
Tony,

Oops, I did it 2 feet in front. Here are the new readings:

I measured the sub at 80db using the onkyo test tones.

My flat REW curve My REW house curve

10hz - 60db 10hz - 70db
15hz - 73db 15hz - 82db
20hz - 78db 20hz - 84db
25hz - 76db 25hz - 84db
30hz - 80db 30hz - 88db
35hz - 86db 35hz - 92db
40hz - 87db 40hz - 92db
45hz - 86db 45hz - 89db
50hz - 88db 50hz - 90db
55hz - 88db 55hz - 87db
60hz - 86db 60hz - 82db
65hz - 85db 65hz - 82db
70hz - 90db 70hz - 85db
75hz - 82db 75hz - 78db
80hz - 80db 80hz - 74db
90hz - 78db 90hz - 70db

I have attached the graphs to show what I adjusted the two presets too. I can't find the measurements but they did come out like that.

Your thoughts

cheers

Graham
 

Attachments

·
Premium Member
Joined
·
15,054 Posts
The dotted line looks good on the first graph It slops down a bit too much on the second Im assuming that Audessy is turned on in the second?
 

·
Registered
Joined
·
3,069 Posts
Discussion Starter · #12 · (Edited)
Tony,

I have re done them from scratch and have the following which look alot better.

Let me know what you think.

I will double check the spl readings again tomorrow to make sure they match these.

One is a flat and the other a house curve. I will do some tweaking to get them smoother tomorrow.

I need to run some REW of my speakers to see what they are doing tomorrow.

Just measured the flat one for the spl test at listening position:

12.5hz - 76db
15hz - 80db
20hz - 82db
30hz - 84db
40hz - 84db
50hz - 80db
60hz - 78db
70hz - 74db
80hz - 74db

Much better now.


cheers
Graham
 

Attachments

·
Banned
Joined
·
440 Posts
Play some sine wave tones while seated in the chair sofa what ever. Use the pc near the seating and please use ear plugs because the tones will tax your ears after a short while.

Play the tones and note where you feel them.

I feel such and such tone around the lower part my backside and partly on the armrest.
I’m starting to feel a mild tone in the chest as well as the under part of the sofa chair, what ever.
I notice such and such frequency on the back of the seating and partly around the armrest.

Things like that, because basically the sine wave is reference guide of show me the bass. Help me help you.:D LOL

Also keep the SPL db near your seating location while noting the SPL db.

My pc is right next to the sofa so its easy for me to use REW sine wave and go though each tone one at time and at different levels.
 

·
Banned
Joined
·
440 Posts
Playing sine waves from 20Hz and going though the range up to 30Hz I can sense it in the stomach mildly at 74dbc to 80dbc. The tone is starting to get louder on my ears the boomy pressure like sound.

Very little vibration on the sofa due to the floor which is a concrete like flooring plus I only have few sub bass speakers plus where there located.

If I parked the large JBL 4645 up close to the back of the sofa it would vibrate silly! Plus subs in cinemas are located up front not behind each seat in the cinema.

Going though 30Hz range at around 31Hz to 32Hz I noticed a slight mild feel of pressure on the back of the sofa.

Going steadily into the 40Hz region I noticed mild pressure on my chest, (only mild pressure) the pressure was more on the ears! 84dbc.

Getting into the 50Hz range still mildly on the chest and it should be greater at lesser at wattage output I only have 300watts for the JBL and 250watts for the Eltax that are sharing the LFE.1 at the same time.

One sub to, deal with such and such range as there are (a few nulls), where I use the other sub to fill in the gaps, the elatx. The eltax when in Dolby discrete 4.1 5.1 will send LFE.1 out of AVR to audio mixer where I use the pan pots to split the signal for sharing between the two subs.

I use LCRS as well for lower end extension and the pan pot sending the lows to the eltax only as I don’t want to over taxi the subs too much.

Anyway I’ll continue with the sine waves.

Backing up slight down to the 45Hz range up to 50Hz there is slight noticeable mild feel in the armrest.

55Hz starting to tingle the armrest as well as the SPL db getting higher at 95dbc I’m using short busts without ear plugs as its only short not long, otherwise use ear plugs its comfortable that way.

Nearing 60Hz the sine wave shifts over slightly as it would higher to one side of the sofa. If I had multiple JBL subs and the room/space to stack them up front the tone should remain uniform.

The tone shifts more to my right ear. If I move side to side within a few inches the pressure will be equal or if I turn my head the pressure will be equal on both ears.

Nearing 70Hz the tone becomes equal on both sides off my ears and the pressure is around 95dbc the vibration is more than noticeable in the armrest.

And the pressure of time is now telling me, to get some kip, I shall continue with this test around late afternoon UK time!

I’m shattered I’ve been up for HOURS!

Hope this will interest you.
 

·
Registered
Joined
·
3,069 Posts
Discussion Starter · #15 ·
Andy,

Thanks for that. I will have a test tonight. I have to say though before I re calibrated the sub as it was all wrong at volume -28db I was getting 104db at 40-50hz. Ouch!


cheers

Graham
 

·
Banned
Joined
·
440 Posts
Andy,

Thanks for that. I will have a test tonight. I have to say though before I re calibrated the sub as it was all wrong at volume -28db I was getting 104db at 40-50hz. Ouch!


cheers

Graham
I concur with the 40Hz to 50Hz I get the same experience within that range at too high a level, if you get my meaning.

It’s rather late now to continue as I didn’t get up till around 5pm and I’ve had other things on the plate, like feeding the cat, making my meal and settling down and relaxing.

I’ll see if I can not finish off what I was doing earlier today sometime around tomorrow because I’m more curious about this than, you are.

I was going to do this just for you, and move my JBL 4645 sub out from the front and park it butt-tight close to the back of the sofa.

I’ve had it there last week for short while but it fails if you move forwards in the sofa you lose some of the impact lows!

I tested it with Star Trek Bluray the bar sequence where it has nice LFE.1 punch that scared the living daylights out of me! I turned it down it was too high!

I ran some sine wave sweeps as well but I didn’t make any record comment on what I’m feeling on the body and elsewhere with the single sine wave tones.

I’ll do better next time! I did notice the lower 20Hz, shuddering the sofa and climbing up to 30Hz that, I do recall.

Anyway I’ll be doing the morning shopping in 9 hours and travelling on the Bournemouth yellow bus with an all-day ticket, £3.70.

The vibrations on one of the buses 5B number 417 vibrates so much it reaches +100dbc! I have to use ear plugs! I have no clue on the frequency unless I had laptop with spectrumlab to record the frequency.

Trust me, it’s a lousy bus I prefer the other bus numbers, there are several 5B on loop circle at least 3 I think.

Anyway Graham, that shows how involved I’m an and I wouldn’t mind that kind of energy in the living room, not! It would drive the neighbours spare! LOL

When those bus pull up across the road, bus stops, the frequency on spectrumlab is within 20Hz to 40Hz I forget which, as I ‘d like to really isolate the window to reduce the frequency level. SPL db of common day with traffic is around +65dbc that’s not good!

Also because of the nature of the building design I, can sometimes feel a (Chinook helicopter) from a mile away, vibrating the floor, as the sound impacts on the building and resonates though the cavity walls and floor, now then!

The Chinook only flies around during summertime so I wont hear it for at least another 6 months, I, mean feel it!


Isn’t there a way to trick REW to record a short few seconds with the mic placed near to you, while playing such and such film? With only the LFE.1 track playing and say just three fronts playing with surrounds muted turned off.

I think there is. Just set the gain up high so that it thinks its recording a sweep and just HIT Start Measure! It should show what peaks are happening within the seated location on some of the LFE.1 effects.
 

·
Banned
Joined
·
440 Posts
Tony,

Oops, I did it 2 feet in front. Here are the new readings:

I measured the sub at 80db using the onkyo test tones.

My flat REW curve My REW house curve

10hz - 60db 10hz - 70db
15hz - 73db 15hz - 82db
20hz - 78db 20hz - 84db
25hz - 76db 25hz - 84db
30hz - 80db 30hz - 88db
35hz - 86db 35hz - 92db
40hz - 87db 40hz - 92db
45hz - 86db 45hz - 89db
50hz - 88db 50hz - 90db
55hz - 88db 55hz - 87db
60hz - 86db 60hz - 82db
65hz - 85db 65hz - 82db
70hz - 90db 70hz - 85db
75hz - 82db 75hz - 78db
80hz - 80db 80hz - 74db
90hz - 78db 90hz - 70db

I have attached the graphs to show what I adjusted the two presets too. I can't find the measurements but they did come out like that.

Your thoughts

cheers

Graham
Wow the AVR generates its own sine wave tones?

I’m thinking of getting a ONKYO TX-SR707 THX select 2 AVR that’s around £599.00.

Between 30Hz and 40Hz always has that common peak within (35Hz 36Hz)

I’ve gone though the tones one at time to aim for +- 2db tolerance with short low SPL db of around 70dbc because the tones at loud level tend to irritate me a little. I adjust this and that EQ filer level and Q and frequency while backing-up and looking over the last few tones to see if they are within +-2db. It’s a tight restriction.
 

·
Registered
Joined
·
87 Posts
Once you have your curve dialed in as you like can you just run the sub a few db's hot to increase the slam/punch effect at the given SPL? Is the slam/punch sensation happens below 80Hz and you have your crossover set at 80 Hz then just turning the sub up should increase your slam/punch.

I used to drive a 2 door coupe with two 10" kicker's that had way more slam/punch then my HT. I guarantee the subs were WAY hot compared to the rest of my system :)

Good luck.
 

·
Registered
Joined
·
3,069 Posts
Discussion Starter · #20 ·
Thanks for that mate.

I just need my neighbour to go out so I can turn it up loud to see how far I could go with that sub. I was surprised that I still go alot of driver movement at 5hz! :eek:

cheers

Graham
 
1 - 20 of 20 Posts
Top