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Old 9th July 2010, 20:05   #16
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So, do you think the various drivers in your or any other home, 2 channel setup are reaching the ears of a listener in the sweet spot at the same time?

the thing is it will be more coherent with no real need for T/A in a home setup because all the drivers are close to each other in the one enclosure whilst in a car you could have mids low down in the doors with tweeters up in a-pillars etc - also the fact that you sit almost centralized at a home system also reduces the need for T/A there

If not, would it not be more imperative to have the arrival time difference eliminated or minimized between the channels rather than the drivers?

its far better to have individual T/A in a car and the reason for this is that the drivers are all at various different lengths away from you - whereas at home they are all in one enclosure thats reasonably far away from you - but in a car thats more of a nearfield environment - not to mention that at home the sidewalls are way further away than you would have from the sides of a car so reflections also play a huge role in all of it

if i just had T/A facilities between channels only - i could reasonably simulate that just by dropping levels of the nearer side with the balance control but that still wont adjust for differences in pathlengths between all the drivers on one side
- so he could purchase a relevant headunit which has multiple pre-outs with individual time alignment but then he still needs more amplifiers to run active to get the coherence he wants and from what i can see he doesnt want to spend that type of money ie new headunit and more amps as well to add to the headunit

and as an example of lack of coherence due to differing pathlengths of drivers have you never, ever heard a "wandering centre" image where for example part of the lead singers voice is on one side and the rest of it is centred - and then depending on frequency hence which driver plays the next song would have it all centred and the next song would revert back to smearing that image

T/A is more useful to prevent problems like that because between channels if all you wanted to do was to centralize the perceived "centre image" then you can easily achieve this more-or-less with a balance control alone
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I'm sorry but I disagree here. I have had coaxials installed in the door panels provide a reasonably good image
sure you could achieve that easily but then with coaxials whats the huge need for T/A because all you are doing is kind of equalising left to right asnd you can do this easily with balance adjustments - yes i agree the delay will be more accurate but because your ears are a poor measuring device and the brain still needs to interpret what the ear hears it is easy to fool the brain by making it think that the nearer speaker is further away by making it slightly softer than it is now - in terms of staging and imaging a good coaxial will also project the sound as well as any component set would be able to if the tweeter were mounted coaxially onto the mid anyway - you would still have the sound being very much in your face and the stage would seem closer to the centre of the vehicle than at the far end of the dash

even with the horns - those are in front of you - all you have to do is make up for the steep upper end roll-of of a typical horn and then try to make the stage get higher - but with a conventional dome tweeter in a door you need the sound to move horizontally forward away from you as well as vertically up - i know that the T/A will help but not as much as just moving the tweeter to some spot in front of you then facing it properly - all that this will take is some labour time and maybe a bit of extra wire (maybe having to rerun that particular wire if you dont want to have joins in your wire runs) - it wont be too difficult to hide that hole in the door and fabricate something in the A-pillars or even kick panels if required but even then if there are differences in pathlengths between drivers on a particular side then it becomes even more important to be running fully active with that T/A - so yes i agree that in the long run the T/A is the answer to fine tune but he shouldnt expect miracles from it if the speakers are in the wrong spot - get those tweeters into a better spot - see how that works out then work on the rest as he goes along ie maybe he could get those pathlength differences small enough so they become insignificant so he uses T/A between sides instead of between all drivers and then to make it perfect even later still more amps to run full active

Last edited by naughty001 : 9th July 2010 at 20:07.
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Old 10th July 2010, 11:58   #17
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Originally Posted by CJP View Post
My home system is a 2.1, the main speakers are 8" P-Audio, BM 8CXA, Co-ax supported by a 12" Eminence Lab 12 Sub in a ported enclosure.
I knew it! but you should go for stereo bass.

2 x Eminence Alpha 15s in dipole powered by a KT88 UL with Visaton B200 on top powered by 300B SE...life's too short.

Last edited by navin : 10th July 2010 at 12:01.
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Old 10th July 2010, 15:41   #18
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Tilt UP.

Rotate the tweeters by 90 degrees, and then tilt up.

Tilting the mid-bass in the Innova won't be difficult. Take a pair of normal MDF rings and get it sanded on one side till you achieve a wedge shaped annular ring. Belt sander would be fast, otherwise it is just a bit of elbow grease. Mount with narrow side above.
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Old 10th July 2010, 19:50   #19
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Originally Posted by navin View Post
I knew it! but you should go for stereo bass.

2 x Eminence Alpha 15s in dipole powered by a KT88 UL with Visaton B200 on top powered by 300B SE...life's too short.
Nirvana has to wait for the time being, my current set up gobbles up a fair amount of space and anything more and wifey might banish me to the street LOL

In the meanwhile, some progress today.

I have just completed Step 0 - some fine tuning of the levels between channels. I now have all the channels at just the right levels, sweet!

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Originally Posted by DerAlte View Post
Tilt UP.

Rotate the tweeters by 90 degrees, and then tilt up.

Am going to try getting Step 1 done tomorrow. Between Church, the weekly grocery chores and getting everything from clothes to shoes ready for the next week - need to figure some time to align the tweets on all the doors.

DerAlte - quick clarification - by tilt up, am assuming that the axis of the tweeters should point somewhere toward the roof light - this is like tilting up at an angle - upwards and backwards. Is my assumption right?


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Originally Posted by DerAlte View Post
Tilting the mid-bass in the Innova won't be difficult. Take a pair of normal MDF rings and get it sanded on one side till you achieve a wedge shaped annular ring. Belt sander would be fast, otherwise it is just a bit of elbow grease. Mount with narrow side above.
Exactly what I had in mind as well. A friend of mine has got a furniture factory - will need to make a visit sometime this coming week and get two of those MDF rings machined/sanded. Once these two work out, I'll do the same for the other two for the rear door as well.

Will update on progess. Have a great weekend gentlemen.
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Old 11th July 2010, 11:17   #20
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... by tilt up, am assuming that the axis of the tweeters should point somewhere toward the roof light - this is like tilting up at an angle - upwards and backwards. Is my assumption right? ...
Yes, that's the general idea. But, the pointing at the roof light would mean more than 45 degrees. Pointing it at the top of the door glass would be more like 15 degrees.
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Old 12th July 2010, 10:23   #21
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Originally Posted by DerAlte View Post
Yes, that's the general idea. But, the pointing at the roof light would mean more than 45 degrees. Pointing it at the top of the door glass would be more like 15 degrees.
thankfully tweeter Freq Resp falls of pretty fast off axis above 10kHz.
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Old 13th July 2010, 14:24   #22
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Quote:
Originally Posted by navin View Post
I knew it! but you should go for stereo bass.

2 x Eminence Alpha 15s in dipole powered by a KT88 UL with Visaton B200 on top powered by 300B SE...life's too short.
Navin, as a matter of fact, I had originally planned to get Fostex Sigma 8" drivers in a backloaded horn (Voight pipe) enclosure. I designed the horn enclosure and had it fabricated. but coudn't source the Fostex units in time. The P Audio units are currently mounted in the same enclosure at the moment. Though they would be better off in a regular ported or sealed enclosure, they perform adequately, but not good enough.

I do really need to get those Fostex drivers or the Vistaton. That is another project waiting to get completed.

Quote:
Originally Posted by DerAlte View Post
Yes, that's the general idea. But, the pointing at the roof light would mean more than 45 degrees. Pointing it at the top of the door glass would be more like 15 degrees.

Sorry, couldn't do an update yesterday.

Step 1 is complete. I removed the door panels, and reoriented the tweeters. They now fire upward toward the roof line and it does make a distinct difference. There is definite improvement in imaging and the off axis response is nice and smooth.

Also discovered that the Eclipse CD5100 Head unit has some rudimentary TA. There is a listening position selector that enables switching the listening position between
1. Off
2. Rear seats
3. Both Front seats
4. Front Right
5. Front Left

I noticed that when I selected the front seats, there is a marked improvement in the image. The image gets better, when I choose Front Left. (I usually sit in the Front Left seat, the car is driven by my driver).

Don't know if this is some basic TA in action or this is some selective 'fade' algorithm. But it seems to work. The Eclipse manual does not mention anything about TA, neither does their web site. Any ideas here, gentlemen?

Step 2 is WIP at the moment. I'll update this thread as soon as I have MDF rings done and mounted.

Last edited by CJP : 13th July 2010 at 14:39. Reason: spelling errors
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Old 13th July 2010, 14:59   #23
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How would it be a fade option ? Fading only reduces the output - not delaying it. The basic logic of these two are different, I would say.
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Old 13th July 2010, 17:17   #24
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How would it be a fade option ? Fading only reduces the output - not delaying it. The basic logic of these two are different, I would say.
, Clarification - I meant 'fade' as in a pre-configured balance/fade that is not really a TA but more like a balance control that balances the individual channels rather than do a true TA.

Am not sure if Eclipse is balancing the outputs or applying some TA when you switch listening positions.
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Old 13th July 2010, 18:40   #25
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I do really need to get those Fostex drivers or the Vistaton. That is another project waiting to get completed..
FE208 sigmas! nice drivers. I have used them with a bit of help on top.
However if you are looking at a horn the Lowthers are far better.
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Old 14th July 2010, 18:12   #26
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FE208 sigmas! nice drivers. I have used them with a bit of help on top.
However if you are looking at a horn the Lowthers are far better.
Can't afford the Lowthers, am still aiming for the FE208 Sigmas, though.
There is an Indian Lowther based speaker 'Rethm', haven't seen this or heard it - but the pics on the website are impressive.

Have you auditioned these?
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Old 15th July 2010, 09:56   #27
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Have you auditioned these?
No not these but I have heard Lowthers in Singapore.
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Old 17th July 2010, 14:10   #28
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Quick update on Step 2

Name:  SpeakerBaffles.jpg
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This is a drawing for the angled mount for the mid bass drivers. I'll be getting these rings done this weekend and will mount them later during the week.

I made some simple measurements with a tape measure and I think this will fit into the door panel without too much interference.

I'll do another update once, these rings are ready.

Thanks everyone and have a great weekend.
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Old 24th July 2010, 22:40   #29
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Step 2 completed today. Yipee!!


I went over to my friend's furniture workshop and we started work. Removed the door panels and the speakers. Removed the MDF rings. Fitted the new speaker baffles to the doors and tried fitting the panels - surprise surprise - it doesn't close!

Here is a pic of the completed speaker baffle.
Time Alignment - Black Magic?-speakerbafflesblank.png

As compared to the MDF ring.
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The revised drawing to seat the speaker into the baffle.
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There was some interference from the edges of the baffle with the panels. Marked out the interfering edges, also figured that the speakers need to be fitted into the ring, and got Manoj, the carpenter to shape a groove to seat the speaker.

Also figured that the outer edge of the baffle interfered with the plastic panels. Marked these out too. And expert Manoj, used a disk sander to very skilfully shape this.

And this is the final assembled speaker.
Name:  SpeakerBafflesAssembled.jpg
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Fitted both speakers into the door and I was eager to try it out. Switched on the music, Mark Knopfler's Sailing to Philadelphia - WOW, the music just seemed so much more detailed, full bodied, and all here. The sound stage has definitely lifted, I can perceive a nice coherent image at the dashboard level. So much better than, the footwell.

Next CD to audition was Pink Floyd Disk 2 of The Wall. Hey You was outstanding, matching the clarity, presence and the wholesomeness of my home system. Bliss!!

The drive back from the workshop was nirvana, I was grinning like an idiot. I was so taken up, I had to bundle the family into the car for an audition drive. Man, they love it, my wife acknowledged that the sound seemed higher up and fuller somehow. This was the final seal of approval. After spending the better part of the afternoon, getting it just right.


Thank you gentlemen. Navin, DerAlte, B&T, Naughty001 - hats off to you

As for me, am looking forward to doing the same thing to the rear door speakers too. Placed an order for another pair of identical baffles.

By mid August, I'll be replacing my Pioneer amp with a Blau 1250 and this Innova will rock!

Again, THANK YOU ALL very much.
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Old 25th July 2010, 16:10   #30
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Yeeeee haaaaa! You pleased, we happy. Enjoy!
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