In general terms, what differences to the sound would flush mounting a tweeter make compared to surface mounting it?

I know that companies like B&W use, as part of their Nautilus technology, a tweeter in a separate housing from the main baffle (see the CDM-1NT, etc) and various other companies use diffusion ribs on the baffle around the tweeter to break up waves from the surface of the speaker cabinet.
The claim that it aids imaging, transparency, etc which are important values I seek in a good system.

I was going to flush mount my MT23 Morel tweeters for cosmetic reasons but then thought that this may detract from their performance compared to surface mounting.

Can anyone make some general comments in relation to this topic?

Cheers,
Winno.

I've always had the best luck with tweeters by building a small metal or fibreglass 'cone' that the tweeters mount onto, and then mounting that to the dash... kinda like the Nautilus tweeter style, but not so flash... works well tho

Generally speaking, it is hard to say.

The area immediately surrounding the tweeter dome will have an impact on the response, due to the short wavelengths involved.

Flush mounting isn't necessarily bad, also consider the area surrounding higher end tweeters ie. esotar, supremo, home audio tweeters etc. :wink:

no difference......

it really depends on where u mount.....sometimes surface is good, sometimes flush is good.

i beleive all tweeters are sealed units right?

Just wanted to point out the obvious, thats all

I gathered you meant one or the other...

I guess it all could have to do with where the tweeter is relative to the mid. Will it be out of time or will it sound like it's coming from the same if not similar spot as the mid I guess is what I was trying to say...

Would it sound like you've moved the image over a little, goes back to what I first said about being relative to the mid (time wise speaking), I guess in a perfect world we'd be sitting between 2 speakers in our lounge room listening to nice music, but since we're in the car it makes it a little hard to be centre.

Does that make sense or have I confused people regarding alignment of speakers being relative to each other?

Uhm...I think you're talking about parallel time alignment there, with drivers on the same channel time aligned relative to each other compared to delta time alignment, where L/R channels aligned differently for non-central seating position...I think...

But anyway, since I've never had flush mounted tweeters I can't comment from experience (comparing it with surface mounted tweeters) but I think the benefit from flush-mounting the tweeters would be to minimise frequency response changes due to baffle diffraction effects, with the surface immediately surrounding the flush-mounted tweeter as the baffle. But then again, diffraction effects tend to alter on-axis FR while the effects aren't that pronounced off-axis. Plus, the in-car early reflections and room response would swamp these effects anyway so I doubt whether we can perceive justifiable differences between the two mounting techniques in a car.

As usual, I could be wrong here... ...still have much to learn from the wise ones here.

Man, this is the sort of discussion that sparks my interest, the "technical, scientific" side of car audio, if you will. Winno, you've came up with great topics man! Keep them rollin'!

Cheers,

Bon

Thanks ICACHA. I've edited it now to make sence.

I was concerned with any destructive interferance that the reflections off what is going to essentially be the baffle (the top surface of the dash) may have if I flushed the tweeters.
In the past I have used a carpet dash mat and this did wonders for the stageing, transparency, air, depth, etc.
I feel that surface mounting and a dash matt will be better but flush mounting looks so much better. Have you guys seen the surface mounting options Morel provide for their tweeters? UGLY!

I was thinking late last night in my semi-lucid state before I finally fell asleep that I could do what Blackrazor has suggested using the tweeter pod housings as a template.

Anyway, keep the comments coming.

Cheers,
Winno.

Bodapa (and all others),
the tweeters will be mounted off axis i.e. not pointing at me but up into the windscreen.
I prefer this method as it uses the 'screen to reflect the sound, therefore raising the stage positively to eye level. It also knocks back a few dB the actual sound from the tweeter making them sound less "in your face" and quite nice in fact. This is less of a concern obviously with such a nice tweeter (but works for the Neo 5 tweeter from Boston Acoustics for instance).

So if the on axis response is mainly affected leaving the off axis performance relatively untouched, it looks like flush mounting could be viable?

It seems that Morel tweeters favour flush mounting if the reviews and information available off the internet is correct.
Some information indicates that constructive reflection from a raised system can in some cases put a peak in the frequency response of the driver. Flush mounting seems to apparently reduce this, providing a more linear effect.

So, there you go.

Looks like I'm going to have to have a little swivel/flush mount kit machined up as the supplied one offers no swivel for the flush mount option.

Winno let me know how you go in greards to getting a swivel/flush mount kit made-up as I could be in need of soem for my arvus components.

Just a note on firing the tweeters right on the windscreen:

This is gonna be tough for me to explain, but here goes...

Imagine a space devoid of anything except a sound source, radiating the sound waves it makes everywhere (360 degrees). Now, put a perfectly flat reflective surface that extend horizontally toward infinity below this source at X distance. The sound waves that radiated from this sound source would hit this surface and bounce back, right?

Now, complex mathematical principles say that you could replace this flat surface with a same sound source at a distance 2X, measured from the original sound source. Still with me? Okay, the 2nd sound source at a distance 2X below the original having the same properties would do the same thing as if the flat surface is still there...I think...

Anyway, what I'm trying to say is mathematically you would have 2 sound sources, one being the original and the other one being its "mirror" image. So when you position your tweeter perhaps you can adjust it so that its mirror image is on axis with respect to you, and maybe it would give the illusion that the sound originates from that mirror image. And you can adjust it some more so that the mirror image is perceived to be at ear level, if you want.

I told you it's tough, I'm not sure whether I communicate this clearly. Besides, this info was taken from another forum and the guy that explained it is an engineer and I'm not. Plus I've never tried this before, don't know whether it works or not.

Cheers,

Bon

I try to get a good mix of angling the primary source (the tweeter) away from me and as such reducing the dB level at my head (because I'm obviously off axis from it). The interesting thing is that Morel designed in and claim excellent of axis response up to 30+ degrees due to their hemi-spherical dome design, etc.

At the same time, I try to apply Year 10 Physics as well (angle of reflection = angle of incidence) so that the tweeter is firing at a point on the screen at about or just below eye level. In this way, the screen becomes like an additional set of tweeters mounted higher again.
My current Mitsi Nimbus allows this set up almost to perfection...shame it's a Nimbus though.

Obviously this is almost impossible to do accurately in most cars, especially the MR2 I have my hopes on due to the very slack screen angle.
This is why simple experimentation is required to get a good result.
It can be achieved, and many times, with relative ease.