20 replies to this topic

[MattyP]

For the past month I've been trying to tune my system, with no luck unfortunately.
I'm not still 100% with the sound (pretty much haven't been from day 1) and I don't want to waste any more money on tuning since I've done enough of that already.

Setup is Clarion HX-D2 running Rainbow Profi Line 3 way splits (speakers in kick and door panels / pods), and Orion XTRPRO subs in ported enclosure.

Main concern is the front stage. Atm there is no parametric / eq done to the front stage what so ever. I've got a bit of silibence up front (can't remember song, but one song in particular by Missy Higgins I can barely listen to loudish because of it), which I never had before when running the front stage through my Audiocontrol DQX (digital 30band eq & crossover). However with the DQX I encounter electric noise which we couldn't get rid of, which is main reason why its no longer running the front stage.

When the front stage was run by the DQX, the highs were really good however the midrange area lacked a bit. However upon changing the wiring so the HX-D2 is rund the show, the mirdrange is absolute joy but now the great highs have gone.

The system has been time aligned, so my question in regarding tuning of the system:

1. Should the time alignment be turn off for tuning? (then sit in middle of car)
2. Should the subwoofers be turned off? (esp if its the top end I'm more concerned about)
3. Is there any tracks on 'MYDISC' that is suitable to help with this tuning?
4. Would the silibence be still there if the tweeter was positioned differently, or does it stay there no matter where it is?

I've printed out all those eq things on the forums here, but have gotten no where. I've found the HX-D2 very difficult for tuning purposes since it only changes one side of the car at a time.

Any help would be appreciated..

MattyP

[shiny_car]

sibilence is typically around 3kHz or an octave above (6kHz). you can try and 'cut' at those frequencies with the EQ.

if you don't have access to an RTA, consider buying a cheapish handheld digital SPL/dB meter, which might cost you $100 like this one:

http://www1.jaycar.com.au/productView.asp?...=&SUBCATID=

despite having an RTA myself (inbuilt into processor), i find it easiest, and more accurate, to use the dB meter. 'my disc' has tones from 20Hz up to 20kHz (track 34 from memory, onwards). i have my volume on the HU loud enough to register around 65~70dB on the meter, then i play the tones and write down on a piece of paper the results. it's kinda rough as the meter fluctuates, but you can still figure out a good average reading for each tone.

i do this with the meter at the passenger listening position, centre, and driver's listening position (ie: ear height). i than inspect and compare, and identify where the peaks and troughs are, then tune the EQ from there.

i also do all of this with the sub and frontstage running. you can do the rears independently if they have an independent EQ and if you have rears. it may also identify areas to tweak the xovers. if for example you LP the sub at 80Hz and HP the splits at 90Hz, but you find a big peak at ~90Hz, you may need to spread the xovers apart more (eg: 80Hz and 100Hz). or if you find the treble is all quite low, you may have a boost on the passive xover you can use.

NOTE that sibilence is not detect on a dB meter! so even if 3kHz or thereabouts is not a peak, you may still want to cut it down.

and don't expect to get it right first time around. despite have what looks to be a very flat frequency response, sometime it still doesn't sound quite right, so you have to go with your experience, and tweak it again (eg: boost more treble, or boost more midbass, etc).

[MattyP]

Cheers Shiny. May go out and buy one right this second :-)

Oh, and if this helps my front stage is setup the follwing way
Tweeter: 2khz up to 20khz
4": 2khz down to 315
6": 315 down to 80

[MattyP]

Alright, another question with tuning.

You mentioned about positioning the mic on passenger seat, centre and driver's side. Would you also do testing with the system just running left speakers only, and then right speakers only, and then together? (or does that defeat the purpose)

My system is currently active Shiny, so does that change anything you've mentioned?

I went and got SPL meter today (the Jaycar one), and was reading the back of it and it said it only reads up to 8khz. Is that an issue, or not really?

Edited by MattyP, 25 May 2006 - 07:19 PM.

[shiny_car]

MattyP, on May 25 2006, 07:16 PM, said:

You mentioned about positioning the mic on passenger seat, centre and driver's side. Would you also do testing with the system just running left speakers only, and then right speakers only, and then together? (or does that defeat the purpose)

run both sides (L+R) whilst testing. this provides an insight into what each passenger will hear.

Quote

My system is currently active Shiny, so does that change anything you've mentioned?

not directly. what it means is that you potentially have more options for tuning, as well as more potential for stuffing it up.

Quote

I went and got SPL meter today (the Jaycar one), and was reading the back of it and it said it only reads up to 8khz. Is that an issue, or not really?

no issue. i use the same meter. i set it to A-weighted and 'fast', though you may find 'slow' easier to read cos it won't fluctuate as rapidly.

because the meter won't detect subbass so well with A-weighting, and 'rolls-off' with treble (ie: less sensitive, but will still detect above 8kHz ) you will find that subbass and treble dB are lower than the middle frequencies. as such, rather than tune the EQ to create a flat frequency response where subbass is the same dB as midrange and treble, smooth out the frequency response, expecting to create a smooth 'inverted smiley'.

ie:
*say when you measure 71Hz, 80Hz, and 100Hz you read 57dB, 63dB, and 60dB respectively, you would then 'cut' at 80Hz, and accept a gradual rise (eg: aim for 57, 59, 60)
*aim for a gradual rise in dB from 20Hz up to around 200Hz then go flat from there up to about 8kHz, then have a gradual fall in dB from 8kHz to 20kHz
*then use your ears (!) to determine if the subbass it too strong/weak and treble too strong/weak, and alter from there

you can create really nice sound this way, without getting too much into nitty gritty and theory.

[MattyP]

Ok, well last night I did a couple of tests before I realised I had my time alignment on, so I turned it off and started all over again.

The attached file is a graph from the meter taken on the passenger side. Looking at it quiet scares me with the number of quick dips and peaks here and there. I did most frequency testings around 3 times to make sure they were accurate enough just incase the meter was wrong.

I used tracks 46 to 52 from memory of My Disc, where it plays 3 different frequencies after each other on each track.




I'm just about to go do the centre and drivers side now, but OMG this crap is nuts from what I can see.

Oh and another question, I assumed by front stage was high passed, however when the tracks were playing like 20Hz I put my hand on the 6" woofer and it was lightly moving :S Hmmmm. On the hu it is cut off at 80hz with 18dB slope apparently

[Pulse-R]

the woofers moving on the 20Hz track normal, as it is band-passed pink noise, so with your high-pass filter (80Hz/18dB) and the track's bandpass (20Hz/24dB(I think)) at 40Hz, you have the 6" at -21dB and the source at -27dB. This is only 48dB below the level you are listening at, so in the case of the volume set at ~70dB, the 6" will still be doing 22dB or so.

edit: to clarify,

at 20Hz, the 6" is 39dB below the 70dB volume setting, so with the sub off, you would still get about 30dB measurement on the dB meter,
at 80Hz, the 20Hz track is about 51dB below listening level, so once again, you'd hear it with the sub off.

just a note of interest, with the 4" at 18dB/315Hz, you still get 20Hz from it, but at -93dB.
so with the volume at 120dB, the 4" will be doing 20Hz at the same level as you're 6" does it now.
hahaha

Edited by Pulse-R, 26 May 2006 - 08:44 PM.

[MattyP]

lol. Well that just went woosh over my head, but I'll read it again sometime soon so I will understand it.

Shiny...you are the f****n man!!!
I did the centre SPL test, but then cbf doing the driver's side since it was going to get time aligned anyway. The centre SPL test was very similar to the passenger one, so using the two as a guide I adjusted the frequencys recommended.

I saved the settings I had before touching the system (just time alignment), one that had all the parametric eq adjustments with no time alignment, and one with parametric eq adjustments and time alignment. The difference was amazing. I can't believe the sound I was getting use to / listening to right now. Probably still needs small adjustments, but besides that its pretty hot!!

After doing the eq adjustments, I then went to get rid of the stupid silibence with success and really no sacrifice in sound quality.

May post up my adjustments over the weekend.

Thanks again Shiny!!

[shiny_car]

good one. it's not so hard once you have a few tools and understanding of how to use them and what to aim for.

graphing it like you have is always interesting to visualise, and makes it easy to target the areas for EQing.

MattyP, on May 26 2006, 07:10 PM, said:

Ok, well last night I did a couple of tests before I realised I had my time alignment on, so I turned it off and started all over again.

it's actually worth tuning with time correction activated. cos i presume you'll be using time correction, so you should tune the EQ with it.

but now you're on your way towards audio nirvana! continue to tweak here and there over the coming weeks and months.

[Gonadman2]

This thread should be stickied...

Its 11:57pm and I'm off to rumage for that SPL meter...

[MaFi0s0]

The JayCar link is broken, would something like this do or can I get better/cheaper?

https://www.instrumentchoice.com.au/store/i...mp;productId=64

shiny_car, on May 26 2006, 05:35 PM, said:

*aim for a gradual rise in dB from 20Hz up to around 200Hz then go flat from there up to about 8kHz, then have a gradual fall in dB from 8kHz to 20kHz

Im confused, arnt most EQs set at a smiley, so why are we doing the oposite?

Edited by MaFi0s0, 06 July 2008 - 09:56 PM.

[shiny_car]

your link is broken too.

here is the current jaycar link: http://www1.jaycar.com.au/productView.asp?...=&SUBCATID=

i notice they have a cheaper meter too, which may suffice: http://www1.jaycar.com.au/productView.asp?...=&SUBCATID=

you're confusing the smileys.

the frequency response and EQ often resemble that of a smiley.

BUT, i am referring to the measured frequency response using the handheld meter. it is inverted for the subbass/treble (ie: dips down rather than rises up) because these meters are not very sensitive with subbass/treble frequencies, making them 'underread' the actual decibels. so it is merely how you need to compensate for the deficiencies of the cheap handheld meter.

as above, the aim is not to create a certain 'shape', but to create a smooth transition from band to band.

[MaFi0s0]

I understand now, thanks for re-explaining, I am gonna order 'my cd' and one of those handhelds from jaycar, will be interesting to see how my current crappy system response is, it only has a 3band EQ(sony drive s) so cant do anything about it anyway.

[BMWTurbo]

If you have access to a laptop with USB port, it might be more worthwhile to spend a bit more money and get a mic and preamp and use a free online based program to get some additional data also.

I'm not certain, but you may even find that the jaycar meter has an output which you could run into a computer input to use the software also. Makes it easier in that you can do the whole test in a few seconds, that would take you potentially 30mins+ to do manually.

[muzzy66]

MattyP, on May 25 2006, 06:46 AM, said:

Cheers Shiny. May go out and buy one right this second :-)

Oh, and if this helps my front stage is setup the follwing way
Tweeter: 2khz up to 20khz
4": 2khz down to 315
6": 315 down to 80

Running active off the Audiocontrol I guess?

How do you have the speakers isntalled? Particularly, what are the angles on the 4" mids?

Personally, first thing I'd do is raise the crossover on the tweeter, if 4" mids aren't too far off axis. 2khz is a VERY low crossover point for a tweeter, and very few tweeters are comfortable playing so low - the ones that do handle it ok tend to be very large Hi-Fi tweeters and even many of those struggle that low.

Personally, I'd try to raise the crossover to 2.5khz or even 3khz if that's possible and see how it sounds, because playing so low is likely to introduce very high non-linear distortion which would not only hurt the sound (can lead to them sounding rough or spitty) but can also hurt the tweeters themselves.