10 replies to this topic

[ubernoob]

I know tweeter positioning get covered a lot on here but it looks like I may be using Vifa XT25TG30-04 tweeters in the factory dash position in my EF Falcon. To fit the tweeter with the waveguide they will have to sit vertically and will be aimed at the base of the windscreen.

If I remove the waveguide I can rotate the tweeters and have them more on axis, which do you think would be better, would I have massive cancellation issues if they were aimed at the windscreen.

I have no TA if that makes any difference.

[Winno]

There are benefits (and drawbacks) for each set up.

On axis will probably give you better/sharper imaging, staging, micro dynamics and transparency.
It will however, result in a loss of some ultimate stage depth and perhaps width. You'll still get good layering but in most on axis systems I have heard, the stage will be moved forward towards you and will initially appear to not be as deep. This is not a bad thing though as this is how many 'good' home systems present things anyway.

Off axis with some form of guiding (windscreen, pillars, dash, etc) will probably net a wider and deeper stage but may also result in the loss of the things you'd gain when in an on axis set up (the micro dynamics, image and better performer placement, etc).

I'd also suggest that you have a play with relative (compared to the next driver down) phase on the tweeters if you run off axis and waveguided. You have said you have no T/A so try just switching the tweeter wires around so they would play 180 degrees out of phase. You may like what this does and it may work, but then you/it may not. Suck it and see I say.

With those things in mind, you'd really have to simply try each position and based on your values, make a call as to which arrangement is best in your car and matched to your liking/taste.

Past systems I have built have used a guided/off axis set up to one degree or another. I've liked what they achieved but felt that I wanted to improve in other areas. This time around though, I am attempting an on axis (well, close enough) set up. Depending on how this goes, I may still use either some rear fill, or off axis small format 'ambient' tweeters (modded Vifas, Scans, or Seas) to give me the best of both worlds.

Good luck.

Edited by Winno, 25 March 2012 - 12:54 PM.

[Big_Valven]

Personally I feel that if you can't keep the waveguide quite on axis the benefits of symmetry and dispersion that it gives you are mostly lost.

Off the top of my head I can't recall if those are the mini or full size versions? The waveguide is definitely more pronounced on the minis if that makes any difference.

This may buck the norm but if you don't have TA you may find the system more "pleasant" in terms of imaging with the tweeters even slightly off axis - ie deliberately sacrificing image focus if it's not going to be accurate anyway. You may find you can get decent imaging though. Time to have a play!

[ubernoob]

Oooh very sorry for the reply thanks for the replies gents, I ended up getting the uber old MB Quart speakers for next to nothing meaning the Vifas remain unused.

After putting decent gear in to my S60 and getting sub par SQ I decided to put the pods closer to the windscreen and have some sort of waveguide on the face of the pods to give untested speakers a chance at sounding OK.

As it turns out they sound amazing, I think I have a slight hump in output at ~4kHz and time alignment would definately help but for what it is the quality is 100% better tan expected.

[ubernoob]

Well this all changed and I need a bit more advice, this is my drivers side pod with the grille trial fit to check alignment.

It will be covered with speaker cloth soon but I would like opinions about the radius in front of the tweeter.



Is it fine as is or could I benefit from enlarging the hole or making it a more gradual radius?

Cheers.

Edited by ubernoob, 20 July 2012 - 05:33 PM.

[lock_monkey]

That should be fine. you obviously like a bit of woodwork . have you or anyone else on here experimented with odd shapped baffles and how they change the sound? seen online in my travels some horns that used interchangeable baffles with the refrenced frequncy responses. so instead of tuneing just the cabinets you also change how the sound rolls off the baffle


maybe abit of pshyc-oaccoustics ---- or maybe something to toy with

Edited by lock_monkey, 20 July 2012 - 10:24 PM.

[SQXPRT]

The angle/profile of the tweeter faceplate is something that Scanspeak and Dynaudio (among others I'm sure) are always tweaking.

[Marc ♫]

I would definitely trial those tweeters surface mounted as opposed to rear mounted with the profiled edges. I did something similar with Morel Supremo's in my X5 and found it drastically altered the imaging ability of the tweeters.
As Simon suggested, that profile is something that speaker manufacturers tweak and adjust ever so slightly to refine it for years (or extensive pre-production modelling).

[ubernoob]

OK guys, thanks, I guess I'll finish the passenger side one and test it grilles on and off to see how it sounds.

I am just a bit hesitant to remove material as putting it back will be difficult.

[syd-monster]

FYI - the little cross hair plastic price over the dome of the tweeter is already a phase plug/wave augmentation/guide of sorts.
hence +1 on mounting the tweeter on surface or even better crossing it above 6Khz, so its minimising the essential frequencies that steer/guide the stage. let your mids do that!.

[ubernoob]

As they are now without the grille they are sitting slightly above flush, if I route the grille from the back I could get the tweeter extremely close to flush, I want the speaker cloth to sit flat so the tweeter can't be 100% flush with the front surface.

I may have to space the tweeter out slightly to get it to sit at the right height.

Apologies for the poor phone pic, the beat up speaker and, oh and the lazy trim job

Edited by ubernoob, 22 July 2012 - 05:12 PM.