This is a Journey into Sound(easy)

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Well, I need some new speakers for my front room. My old mains, (well documented in this forum), have bitten the dust due to the Audax HD3P tweeters finally starting to leak.

Eventually, I will be building a fully active all singing and dancing 5 way HT setup, but to get going with Soundeasy, a new program for me, I have decided to use up some of the drivers in my collection to create a new three way stereo pair for interstitial use.

What I intend to do in this thread is to go through my experience getting to know Soundeasy, posting problems and solutions as I go, hopefully helping others avoid my errors and come up with a fully documented design process that will be of general use. The specific design is unlikely to be of course, as I have some very unique drivers, and don't intend buying anything new unless I absolutely have to. ;)

So, to get started. My testing laptop is a fairly old P3 running XPpro, and I have a M-Audio transit as an audio interface. The jig pictured below has a single channel amp built in, along with basic voltage deviders to protect the sound card inputs, switching for calibration and mic/amp and testing is done with a 10 ohm load resistor. Nothing complicated there.
 

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Testing space is fairly limited, so I will be relying on lots of different techniques to get usable measurements. One of the first things needed, after the jig, is a way of mounting the DUT. I glanced around my workshop, and saw a nice lump of 12mm MDF, 600x600mm. This will serve as a test baffle and mounting frame for the driver, so out came the trusty router and a 250mm diameter hole was cut into the centre, a 10" being the biggest driver I'm likely to test for the time being. As I go, I'll make up different size adaptor pieces for other drivers that fit into this cutout size.
 

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So why not a 1m square baffle as is industry standard, I hear you ask. Well, ceiling height in my workshop is 2m, so measurements of below 250/300Hz I will have to go for near field/ close miking anyway, and the path length of the rear wave will still have further to travel than the first reflection. 600mm is a good compromise for my space, big enough to mount decent sized drivers, yet not too bulky to store.

So back to the construction. A few rebates and some glue and screws, and it fits firmly to one of my portable workbenches. I could have built a stand for it, but why bother! :)
 

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Well, I definitely couldn't fit one of those in my workshop! It just shows how things have changed, just about everything used to be referenced to a 1m baffle in my day.

I'm using SE V14, I originally bought it as V10, but took advantage of the wonderful upgrade terms so I could use USB soundcards properly. If you have an earlier version, then upgrade now!

It's the kids' bedtime next door, so no measurements tonight, time to start sorting through my drivers for possibles.

Just a quick plug for SE newbies, get John K's guide. It's worth every penny and gets you over the initial steep bump in the learning curve.;)
 
ShinOBIWAN said:


Get that AV15 going :D

haha I have four of those (one is hooked up as a linkwitz transform sub at the moment--they're eventually going to do dipole duty) but am lucky to live in a brick-walled row house that transmits almost zero low frequency information between houses.

the basement apartment, however, is another story!

Pinkmouse: i just got the JohnK guide and, yes, it is incredibly helpful.
 
I shall read with interest Al. I was about to order SE14 next week, but this afternoon I got accepted into a post-grad course I've been wanting to do for some time, so poverty will prevent until 3Q. By then I expect you to have me as an armchair expert.

Hurry up lad.
 
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Well, working all day and getting home too late to make much noise means testing is on hold 'till the weekend, but here are a few pics to keep you going.

Part 1: The top end. From left to right, top to bottom.

Calrad CT5. Looks interesting. Box says 100db efficient, 2-27K.
Unknown. I have no idea...
Audax TM020G7. Good budget tweet. Sounds excellent for the price.
JVC HS1101-01A. I think this is similar to the Radioshack one that seems to have a good rep on the web.
 

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Part 2: In the middle.

Dynacord C110K30A (branded Fostex). Very sensitive, sounds pretty good.
Scan-Speak 13M-3808. I know very little about this, looks very 80's, but well built.
Audax AP100Z0. Seriously good driver for the price, (£5!) this is the last pair I have from the Maplins closeout deal from a few years ago.
 

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Part 3: Bomb da' Bass

Kef B139. Supposed to be in my tapped horns, but I feel a TL calling...
Volt B220SS. Awesome driver. Another possible TL
Coral 10L-60. Much prettier than the other two. I wonder if it would work in a TL? ;)
 

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pinkmouse said:


We shall see. I certainly expect to make quite a few ****-ups along the way, so if you learn from them at least you'll know what not to do! :)

What's the post-grad BTW? Anything fun?
My definition of fun usually doesn't include C programming <shudder>. Bourbon, birds and loud R&R are more to my liking. Preferably all at once in a kiddie-pool full of jelly.
I'm moving into industrial electronics and need to do some updating of knowledge and skills.
 
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