# CARA Forum



## Anthony

Hey all, 
I just got back into using CARA (Computer Aided Room Acoustics) more and more for work and home. I originally just used it for speaker placement and got good at that, but now I'm trying to experiment more and more with room treatments, pre-build design, and the like.

The original CARA forums are shut down and if they moved anywhere, I can't seem to find them.

So I figured I would start a thread here for people to ask for advice, debugging, or how to interpret results. We are well "indexed" on google, so anyone else looking for CARA help can join up and participate. 

Finally, I hate Mega-threads, so this is really an experiment. If it turns out a lot of people start asking questions about CARA, we can ask Sonnie for our own forum :daydream:

For all I know, there might only be four of us who use the thing!

Any thoughts on the program or experiences to share? I'll start:

Pros:
Powerful program, correlates well with observed measurements, models most wall and floor treatments, nice speaker library (including dipoles), cheap

Cons:
Steep learning curve, garbage in/garbage out, some results hard to interpret, large room calculations take hours to calculate (even on good computers)

Links:
Rhintek: http://www.rhintek.com/cara/cara21desc.php
CARA Homepage: http://www.cara.de/ENU/index.html


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## atledreier

I used to use CARA quite a bit, and still do on occation. I find it's decent for estimating reverb and decay, but not so good at positioning. Even doing a simple room with very many iterations often show some pretty inaccurate results. I LOVE the auralization (or whatever they called it, the preview samples). That give you a good estimate of what got better.


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## Anthony

Oh, I had the opposite results with placement. I spend several hours one day moving my sub through 20 positions running an REW sweep and repeating to choose the proper one. Did similar things with my mains, but with only about 6 positions each. Found the best places for all.

Then I got CARA about a month later and built a model of the room. Wouldn't you know, it picked the EXACT places I found experimentally. Since it was my first time, it took about the same about of time (2 hours or so), but with much less back breaking effort to move a 100 lb sub around 

Now I have a dipole sub, which has been more of a challenge to model. I think I'm going to have to make my own fat panel and tweak its FR to match (even though it's a cone sub).


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## Rambo4

I have used CARA as well. I just wanted to use it for sub placement, but when I built my room and ran the placement within the boundries I suggested, it had the subwoofer in the front third of the room, several feet from the front and side walls, and on a 45 degree angle to the seating. There was no way my wife was going to let me get away with that.. :whistling:

Awesome program though. Very fun to experient with. Still have troubles setting my speaker properties correctly.


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## Bob_99

It has been a while since I've used it but this thread may motivate me to go back and play with the software some more.

Bob


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## atledreier

Yeah, me too! I'm installing it right now.


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## Anthony

Proving that they are still supporting this product, there is an update to both the 3d graphics DLL and CAD executable.

The CAD executable fixes a really annoying bug when you try to add speakers. The 3d graphics module made panning in a complex room much faster. Also, remember to make sure you have hardware acceleration on, if you graphics card is worth its salt. By default it is not on.

Also, there are more materials and a couple of stock absorbers available for download. Remember to add your furniture. My room was supposedly too ringy in the midrange (but I did not observe this). Added the couches and things looked pretty good (which is closer to what I've observed).

Downloads are here:
http://www.cara.de/ENU/patches.html

Materials and absorbers are available on the same site.


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## atledreier

Cool! Didn't know about the patches! Thanks.


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## Bob_99

Yes, thanks for the information about the patch. It has been quite a while since they've done anything with the program and I figured it was heading to be an abandoned product. On another note, has anyone installed this on Microsoft Vista? I've had problems with other older products and was just curious to have any information before I do the installation.

Thanks

Bob


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## atledreier

atledreier said:


> Yeah, me too! I'm installing it right now.


Actually... I'm not... :crying:

My CARA program disc is gone... :rubeyes: I've probably left it on my desk or something sometime. I have the other two, the training disc and the test disc. Anybody care to send me a zipped copy of the contents? raying:
I realize maybe I'm violating some copyright rule on the forum here now :shh: , but I do own the software. I have the package and everything but the important program disc... :dontknow:


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## Sonnie

It is not a problem if you actually own it.

We would be happy to host a forum for them if it is a popular enough program and the CARA owners are willing to work something out.


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## Anthony

< runs upstairs to check on my disc and license code >

< runs downstairs to computer > whew!  

Maverick, you have a PM, but I would contact the CARA folks directly. If you have your license code (which you would need anyways), they would probably send you a disc for the cost of shipping. I've had this happen with other software and usually the companies are pretty friendly about it. Most of the cost is in the license and not the packaging/discs/etc.


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## atledreier

It's been a while, but I'm pretty sure I've never entered any license code for CARA. I have the normal three-disc jewel case with a manual, the program disc (used to), a 59 track test disc and the training CD. There's also a registration form which I never used (yeah, I know....).

I've looked EVERYWHERE.... :scratchhead: This is annoying! :hissyfit:


This is what came in my box, in addition to the CARA disc:


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## Bob_99

> It's been a while, but I'm pretty sure I've never entered any license code for CARA.


There is a license number and mine was pasted on a label inside the case.

Bob


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## atledreier

That's weird. Is your case the same as well? I have absolutely no recollection of any license. I have also moved my install several times between laptops and desktop PC's with no issues. I'll try to find out what the guy who sold it to me is called. The distributor for CARA in Norway is a single guy, not a company.


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## alan monro

Anthony , gooday . I have cara , have had it for years never worked out how to use it . If i can get enough info i would certainly use it . Kind regards . Alan .


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## Anthony

Hi Alan, welcome to the thread. 

I am definitely not an expert, but among all of here should be enough help to get you started. First off, the help files (at least in my 2.2 version) are fantastic as to getting you started. The CAD program could use a little refinement, but for the most part is pretty easy to pick up.

Did you have any specific questions? My advice would be to start with one of their default rectangle rooms and just play around in the CAD editor. Get a feel for how to drag things around, resize things, add textures, etc. I understand it can get a bit confusing (especially since some options are available on one tab and not another even though they are similar).

Definitely get the patches, though. It fixes a very annoying bug regarding loading speakers. Sometimes mine would crash altogether (with any changes I had made).


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## alan monro

Thanks Anthony , I will get started and will definitely get back Kind regards Alan .


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## Bob_99

atledreier said:


> That's weird. Is your case the same as well? I have absolutely no recollection of any license. I have also moved my install several times between laptops and desktop PC's with no issues. I'll try to find out what the guy who sold it to me is called. The distributor for CARA in Norway is a single guy, not a company.


Sorry for not getting back to you sooner but no, my case looks completely different. Perhaps the changes in the case included a change in the usage of a license number. I can't remember how long ago I bought it but if I had to guess, probably 2.5 years. I'll try and post a picture later.

Bob


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## atledreier

I've had mine for ages! lot more than 2,5 years, anyway.


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## Anthony

Maverick, 
The company that makes the software only has/had like 3 people, so support may not be timely. However, someone is obviously working on it, because the most recent update was from only a month ago. Hopefully they will hook you up.


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## atledreier

Yeah, hopefully... Without a POP or a license code I'm pretty sure I'm out of luck, though. My previous installation had migrated through several PC upgrades and re-installs via a backup drive. Some time ago I decided to let it go, I could always reinstall later if I needed it... Ironic...


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## scot

FYI: Cara's next release is v3.0. It is, of course, over a year late at this point but supposedly they are getting closer. The new version properly understands things like monopole ribbon speakers, rounded surfaces, multiple CPUs and other system enhancement (probably just mmx optimizations).

I haven't heard anything recently from them though. Might want to ask for yourselves. 

The one thing I asked about that would really help is a distributed computation capability. Put a network of a few thousand people together and you could have SERIOUS power to calculate rooms...

BTW: the forums were closed due to spam. I sent many options to the admin on how to help with it, free, but they didn't take me up on the offer. Rather than fight the spam they closed the boards, which I am sure hurt the sales of the application.


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## atledreier

My copy never had a license code or anything. I found my copy, so I'm set. 

I usually start out with a very wimple room, just the plain walls and speaker/listener setup. This makes optimization alot faster, and allow you to run at a higher resolution (max rays). I can usually confirm my measurements with CARA, but require pretty high max ray setings. ANd somehow (might be random) I get more accurate results with odd number of max rays. No idea why, could be some algorithm artefact. 

Note that the default scaling is linear frequency, so it's represented a bit differently from what we're used to from REW.

I've had my copy a long time, and still use it all the time for myself and clients.

Make sure you model your speakers pretty accurately. I used generic subs and got weird results, but after modelling my sonotubes properly (a tall box, driver in bottom, port on top) I got much more accurate results.


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## Afi

I have got my Cara back since new CrossOver makes it work! I tried it many times with wine but it never worked in linux. Do you people know any place where you could get more speaker and furniture models? Any news about new Cara?


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## scot

Not yet. Give them an email. They are really good about getting back with people.


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## t7492b

Hello all,

Not sure if this thread is still alive, but I just got a copy of CARA 2.2plus (trying to figure it out). I got a license code label stuck inside the CD case, but it wasn't asked for when installing. Running fine on XP in VMWare Fusion on a MacPro.

Does anyone know sources for more 3d objects (furnishings) and especially, absorption coefficients vs frequency for other materials? I'm specifically searching to no avail for coeff vs freq for horizontal faux wood blinds, both open and closed, over glass windows. I'll probably get drapes ultimately, but I'm curious about the blinds.

Thanks,

Tom


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## Anthony

They used to have some at the downloads section of the CARA site. I've never used them, though, just the stuff that came by default.


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## gonnatell

Hi, guys! I need ideal reverberation time curve according to AES "Multichannel surround sound systems and operations" at my CARA.​How to narrow default ideal curve after i calculate acoustic ambiance? I also tried to create my one ideal curve but it needs some special formula... Please help​


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## Maksim Vus

gonnatell said:


> How to narrow default ideal curve after i calculate acoustic ambiance?​


I have the same question. 
Does anyone know how to customize the range of ideal curve? :help:


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## Anthony

I have never tried that, from what I can tell it is hard-coded.


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## gonnatell

Anthony said:


> I have never tried that, from what I can tell it is hard-coded.


Yeap, it is. And no upgraded versions of CARA during last 6 years ((.
What kind of programs are you using to calculate RT60 at listening room?


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## SierraMikeBravo

Cara isn't bad if you have the time to just let it run. The only problem with it is that it uses ray tracing in order to calculate the response of the room. This is fine, but the calculation time is enourmous since you need to factor in one value for every single boundary, as well as pieces of furniture resulting in a calculation time that can take months...literally. As an experiment, I attempted to run a calculation using 8 reflections on a dedicated computer. I decided to stop it after 5 weeks. Yes, it took five weeks just to get that far. Yikes! Minimum calculation value with any accurate results would be 6 in an empty room. Anything over 3 or 4 boundaries results in the increased exponential time factor. Unfortuntely, anything less than 6 for a rectangular room is not accurate.


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## danielh

In the hope of re-activating this thread, i would like to add my post. I have used CARA in the past and plan on using it in the future. Therefore, i was hoping to find an active forum for CARA users.
The last post here was 5 years ago, but hope dies last...
Also, it really would be awesome, if there was a v3 of CARA. It desperately needs multiprocessor support


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