[Invinsible]

FINALLY Phew !!!
Rishi, Now it's time to play around with the TA, Mounting and P.EQ to add some more kicks to the sound. Try the EQ at the said points I had mentioned am sure it will make them sound even better.

Cheers!

[navin]

Originally Posted by greenh0rn

Guys an important and critical update- I just reversed the polarity of passenger-side tweeter and the harshness is totally gone!!

Now just one quick question to the gurus, will it matter if I reverse the polarity of driver side tweeter 'instead of' passenger-side? I wanted to try it today for myself, but had ran out of time and also the sky got too dark.

one way to find out is to sit in the passenger side and listen.

normally it is recomended that the tweeters on both channels be wired to have the same polarity. if the harshness is gone it probably is because the reverse phase has now created a hole/notch in the 3K range (nominal XO frequency).

Green, it is nice to see someone experimenting and reporting the findings here. It will raise the collective knowledge of this forum.

[greenh0rn]

Originally Posted by navin

normally it is recomended that the tweeters on both channels be wired to have the same polarity.

I can definitely try out this today and see how it works out.

Originally Posted by navin

Green, it is nice to see someone experimenting and reporting the findings here. It will raise the collective knowledge of this forum.

Thanks Navin, the idea behind starting this thread was as much to solve my own problem, as to serve as a point of reference to the newcomers.

I think we should also create a new sticky thread on technical issues that degrade SQ- things like phase shift, lobing, smearing, out-of-phase or polarity. People like me who thought connecting components' + and - to + and - of the amp was enough have so much to learn!

[Invinsible]

Just to add what Navin said. I have tested all 3 ways extensively spending hours sometimes days listening to all time music with driver side polarity on tweeter reverse, than passenger side and than both. All I can say every change changes the imaging. Once the system is TA'd it's best to experiment with tweeter polarity in every way. I have my tweeter polarity reversed on driver side and puts my image in dead center. Another thing that is imp is the PLD between midbass and tweeter which comes into playing with the case of tweeter polarity. In my case my PLD is -2 inches, which means by distance tweeter is close to me than the midbass. Once I TA'd I notice that the tweeter was reaching my ear first than the midrange also due to reflection on the screen. Until I switched the phase/polarity on tweeter I would get the driver tweeter slightly more audible than the passanger. After I changed the phase on left tweeter and noticed the highs, guitar, piano shifted to the left than center, changed it back to inphase and chnged the phase on driver side. Noticed the instruments sounded more in center than the left or right in front me.
Also tried this with placing the tweeter facing onaxis and it dint seem to work. What worked than was having both the tweeters in phase. And again founf the instruments in center.
So back it was to Apiller stock location and with the driver side tweeter out of phase.
With both tweeter out of phase noticed that the guitar and the voice wasnt that clean. Wasnt upto the mark. Details were missing. Again am using morel xover which has the xover point set at 1900 at 6db slope. Where even some midrange is filtered in tweeter.
I suppose there are lot of factors which comes in picture when playing in passive form reflection, mounting position and location, diffraction, PLD, xover points on crossover, and tuning it.
If done rightly passives can made to sound as good as active.
Also tried with both the midbass out of phase, expereince was completely different more on this later.

[greenh0rn]

Originally Posted by Invinsible

Also tried with both the midbass out of phase, expereince was completely different more on this later.

Do write about it soon, we are all ears! ;-)

[greenh0rn]

Ok after a longish listening session today that involved heavy metal at moderate to high volumes, I have another unique experience, rather irritation to report. The tweeter harshness that so bothered me has reappeared in an all new avatar, this time it's only causing problem in the right ear (driver's right ear, facing the window). The left-side ear, which is actually in the line of fire by passenger-side tweeter is surprisingly not affected at all, but in the right ear I could feel a little numbness, or early signs of ache after about 25 mins of moderately loud music.

It is almost as if the sound energy from passenger-side tweeter is hitting the driver's glass window, getting reflected, getting amplified and then attacking the right-side ear. Is this a correct diagnosis? Any suggestions on how to deal with this?

This is by the way the same setup from yesterday - all speakers are in same polarity EXCEPT driver-side tweeter, which has reversed-polarity. Looking for your feedback and suggestions.

[abhibh]

greenh0rn have ya thought about changing the tweeter position ? Experiment with that too maybe you will get better results.

[greenh0rn]

Hey Abhibh, yeah need to try them a bit off-axis as well. Will do it today or tomorrow evening and report- I still need to give them one more long listening in their current position.

But have you ever come across window-glass reflections creating 'this' type of problem before (only right-ear gets attacked, left-one is left alone).

[Invinsible]

Rishi, best would be you place them off-axis. Also, with off-axis it will cut of some freq response above/below 10Khz and make them sound a little smoother incase there are any peaks present. Apart from that some tweeter are made to be sound better on-axis and some are for off-axis. Make use of the EQ I would say which may help in cutting or boosting some freq. response and can soften out the response.

Regarding the Midbass, well I had tried setting both the midbass out of phase. The response was good. This won't be much useful if one is not running the rear speakers. I have front comps and rear coax running of at 3 way active mode, which means under "HI" setting the comps are running and under "MID" setting the coax are running. I have rear coax bandlimited at HP 200hz 18db slope and LP at 3.15khz at 12db slope and the TA was applied to them. The trick that worked for me both these Hi and Mid setting on the headunit has their Phase control. After switching the polarity on mids the output was down by 3db. So had to set the gains little higher. Once I did that the sound coming off was good but a slight drop in midbass, so made the use of the EQ. The sound was little shallow than the normal. The Soundstage was getting pulled at the left, the left tweeter seemed to be coming early than the right one. This wasn't happening when the midbass were in phase.
Now here's the catch, I reversed the phase of the rear coax that is "MID" from the HU. The Soundstange was back, in center high up on rear view mirror by adding a bit of reverb effect or rather I would say a concert effect to the sound. Did some fine tuning on the TA, The vocals were in center and the instruments were being played around it. All the low freq from the center was coming off from the dash. Kick drum was kicking hard with the sub being crossed LP at 100hz. It added a feeling of sitting in live concert with wider soundstange. One could easily say where the vocals, guitar and drums were playing and forget if it was playing in a car. Rather it was like in a larger room as there was more presence. The best was to listen to Pink Floyd "Wall" on this and it really did made me believe that I was indeed in a live performance. Every type of music that played had much more presence in center. Though this type of setting cannot be enjoyed in every genre of music. But when ever I am in the mood to listen to something like this with all those classic Rock or live recordings I switch back from usual setting to this. I suppose this sense of presence wouldn't have been possible without having the rear coax and its not just for rear filling but band limit them and they can add good presence to the sound with right amount of gain and accurate TA setting.

[abhibh]

Originally Posted by greenh0rn

Hey Abhibh, yeah need to try them a bit off-axis as well. Will do it today or tomorrow evening and report- I still need to give them one more long listening in their current position.

But have you ever come across window-glass reflections creating 'this' type of problem before (only right-ear gets attacked, left-one is left alone).

To be honest yes i have faced a bit of similar problem. In my car (Alto) i think the ORVM pod is the best tweeter placement (Might be for Santro too).

Maybe due to the difference between you and right tweeter is less your are facing such problem. Have ya checked maybe tweeter is at fault. Try changing left tweeter with right one.

[greenh0rn]

Originally Posted by Invinsible

Rishi, best would be you place them off-axis.

Originally Posted by abhibh

To be honest yes i have faced a bit of similar problem. In my car (Alto) i think the ORVM pod is the best tweeter placement (Might be for Santro too).

Ok folks, I moved the tweeters around to see if i like them off-axis, and the answer is a big and resounding no! But, and a J LO but, I have great news to report. I changed the right-side (driver's) tweeter's polarity as well (now both tweeters have reversed polarity from the time when I couldn't stand their harshness) and boy, is the result dramatic!

The right-side harshness (maybe it was driver-side tweeter after all that was causing a bit of pain in my right ear) is now gone as well. I say good riddance. The tweeters sound very well balanced now, and for the first time I've begun to appreciate the true clarity that a good source unit (Clarion DXZ785) combined with good speakers (Illusion Electras) can provide. The sound of fingers moving on guitar strings (Sade's song 'By your side') is a hair raising experience to put it mildly! Kya bajj reyla hai bap!

Now, we just need to find a way to permanently (flush) mount the tweeters on a-pillar of Santro Xing, the double-tape doesn't like the a-pillar plastics very much and keeps falling off. FG Pods is an option, but they'll ruin the stock interior look (not that much of it remains after those 6.5" woofers in the doors).

Tomorrow I'm off to Faridabad for one final round of testing the tweeters - this time on the doors - and whichever location sounds best will be fixed permanently.

From my learning so far, two lines of suggestions for folks who'll go my way (mount tweeters on a-pillars or dash) in future:

1. Try and change polarity on one tweeter, then the other, and finally on both. See how it sounds (bright, natural or laidback) with the three combinations before you start doubting your ears, your speakers, your car, your wife/gf, your God, or wondering whether you need to go active.

2. Definitely, and by all means, listen to the tweeters both on-axis and off-axis before you fix them permanently.

[thelord]

Congrats for finally getting the sound you were looking for! And I have to say, this is an extremely useful thread for all folks looking to experiment with the tweeter location.

Installation on A-Pillar should be pretty simple. Atleast it was on an Alto. What you need to do is remove the A-Pillar pads, punch 2 small holes, place a backing plate and screw the tweeter swivel mount to it. Its not the perfect solution where the tweeter is complete pushed inside the A-Pillar, but I guess the easiest way. Looks clean too, no wires and stuff.

[greenh0rn]

Yeah thelord, in fact I am thinking of using the same 'surface mount' for my tweeters - just waiting for the pods to arrive from Mumbai (or perhaps I'll pick them when I go there in 2 weeks). The perfect solution ('flush mount' is what it is called) won't work in Santro A-pillars, or for that matter in A-pillars of many cars, because the space behind the plastic is too less for the tweeter to stand be perfectly flush.

Lastly, wanted to share more of my learning about tweeter locations:

1. If you are experimenting with an A-pillar location, try and keep tweeters sufficiently higher from the dash so that there are no obstructions or protrusions from the dash coming in the way of tweeter firing. In Santro, this means keeping tweeters around 3 inches above the dash. If the dash indeed comes in the way, you'll hear reflections and perhaps smearing at loud volumes, which will jar your music experience.

2. Locating a tweeter away from mid-bass creates many different phase relationships between the two speakers. These differences can arise out of various possible combinations, whether both speakers are firing from the same plane, on-axis/off-axis, path-level distance (PLD) to the listener's ear etc. Getting the phase-relationships right for each possible combination is more than half the battle in getting your components to sound their best. In fact, some premium component-systems even try and account for the various possible phase relationships by allowing various settings through their crossover (the best example I can give is Frank's new Alpine SPX-17PRO components, which has various 'phase link' jumper settings to fine tune the phase relationship for various types of tweeter installs). For other components (and for people going active), the first step is to reverse polarities of the tweeters one by one and then listen for the best sound. In active mode, I'd have loved to see a variable phase (0-degree to 180-degree) control, but all that my Clarion offers is an either/or 0/180 switch.