7 replies to this topic

[Winno]

Over the past week I have been having a go at setting up my front stage time alignment.
I've read on the net a few documented methods but in the end I just input the numbers into the Clarion and it spat the sound out the best so far. I guess they might know what they're talking about over at Clarion and I can see that the HX-D2 is actually making a liar out of me by being very, very easy to use and set up...once you get around the ergonomics that is.

Anyway, after getting the L/R levels set, punching in the distance numbers to get L/R/Sub phase pretty spot on I still wasn't happy with the stage height right at the far left and right of the stage.
The centre is very good but the edges needed some work.

I have wanted to keep the dash pods with the MT23s and CDM88s where they are for ease of intall, etc and this meant that I couldn't really change too much to work on things.
I can swivel the tweets and that's about it.

Anyway, i decided to play with blocking the most on axis sound from each of the tweets and mids and move to relying more on reflected sound.

The pics here show some clear file cover plastic cut into very rough squares and simply sat in front of each driver.
From the listening position I cannot actually see the driver domes and the flare on the mid.

Peeking over the top

 DSC_0115.jpg   51.13K   14 downloads

As seen from the driver's seat

 DSC_0116.jpg   46.02K   14 downloads

Ok, I kinda knew what to expect but wow!
I had to adjust the L/R level a single notch to the left and now the edges are definitely higher and as a bonus, the central vocals on the Audison and F1 cds are a few metres further back (which is what I wanted btw). The imaging right across is so palpable now with all instruments easy to distinguish and place.

And as an aside, I am really liking these Morel MT23 tweeters. I was worried that they'd be too soft but the have a really sweet and extended sound that lacks harsh edginess, smearing or mushiness and are so easy to listen to.

Next up I'll try mocking up something a little more attractive in black and perhaps add some flocking to them.
Also to come, clear rubber sound diffusion dimples on the windscreen around the inside of the mid and outside of the tweeter...

Anyone else done anything like this with waveguides?
What did you do?
What results did you get?

Edited by Winno, 08 November 2009 - 04:49 PM.

[BMWTurbo]

I mucked around a while back with horizontal firing pods similar to what you have and came to very similar conclusions in the end.

As per the GURT theory you really want to use the reflected sound as the 'source' and eliminiate any direct radiating sound from the driver (well as much as possible). This will only diffuse and 'increase/nuddy' the percieved image location.

I found that I could get great depth with screen fired drivers, but the response was peaky and very difficult to tame in the higher end. I also noticed that although I could get the staging and focus 'good' I was never happy with the lack of detail and roughness in response with the reflection from the screen.

I did run a 3inch widebander in a horizontal pod with a rough 'guide' on the front to set the driver deeper into the pod and again came to the same conclusions re lack of focus and roughness in response. The exact same drivers in the same spot on-axis lost a small amount of stage 'depth' and possibly a fraction of the width, but focus and detail increased in leaps and bounds.

[shiny_car]

cool experiment, but obviously looks pox. so your challenge is to make it look 'like it belongs there'.

[Marc ♫]

Oh no, I see where this is going ...

First we had to ban blu-tack, next it will be 'little blue squares of plastic'! Hehe

[Winno]

I've experience with drivers aimed away in the past and I know it has the potential to introduce a host of other issues. In this case though I wanted to eliminate or reduce at least the phase issues you get with direct vs reflected sound and I have been pleasantly suprised at how integrated and well blended everything is (and I have not even gone near the EQ yet!) I would say that this has been a success as the sharper focus is a sign that the phase cancellation is almost gone now. The fact that I am working with such good (and underrated for that matter) drivers has made this task so much easier.

Shiny, you have a way with words my friend...haha
Will be working on a solution tonight actually. Pics to come.

Marc, on Nov 9 2009, 12:16 PM, said:

Oh no, I see where this is going ...

First we had to ban blu-tack, next it will be 'little blue squares of plastic'! Hehe

It's ok, I'll make em black then and use drawing pins because I've run out of hot melt glue...

Edited by Winno, 09 November 2009 - 12:23 PM.

[Pulse-R]

If the off-axis sound isn't right, then what you have done will help.

I tried the similar thing a couple of years ago, also with MT23's.
The problem I had was that the sound stage developed a 'double image' of the reflected sound off the windscreen, and the leakage sound around the 'baffle' piece.

one of the problems with a good sound is that you can hear all the imperfections more easily.

[Marc ♫]

Haha winno ... no worries mate. Then it's all good

Seriously though, thanks for showing us what your experimenting though and what you're finding!

[br85]

It's so good to see some sensible out of the box thinking! Well done