reading frequency response graphs

[thylantyr 10+ year member]

Some loudspeaker designers are forced into that position when they work

for manufacturers. They want the cheapest drivers and they make you design

a crossover to make it sound acceptable. You are talking drivers that cost a few bucks

in some store bought product.

For DIY, there are folks who thrive on this. Lets get a cheap driver and try to make it

sound acceptable by making a clever crossover to fix issues.

For me, I just want to find a well designed driver that I'm able to plug into the amp

and have it sound good ''' as is "" without having to 'fix it' .. I pay more but the loudspeaker

is easy to work with and fine tune later.

For example, the 49 cent NSB. It need 6 cone treatments to fix gremlins. Also, a steep

slope helped alot to smooth out the sound. For full range duty, a phase plug mod helped

the top end. That is alot of work and modding for a 49 cent driver to make it very cool.

I even did coolant tests to boost power handling from 5 watts to 400 watts.

Plus, I had to sand the frames and paint it. Looking back, I'd rather tell the customer

to buy a $25 midrange because there is less labor to fix issues and you can focus more

on construction than driver mods.

 

[jaygeorge1979 10+ year member]

i respect your opinion on that one, but at the same time i think its kinda kool that with a little elbow grease you can turn a 49 cent driver into something acceptable...so now i ask how do you do:

-cone treatments?

-a phase plug mod?

-coolant tests?

 

[thylantyr 10+ year member]

i respect your opinion on that one, but at the same time i think its kinda kool that with a little elbow grease you can turn a 49 cent driver into something acceptable...so now i ask how do you do:
-cone treatments?

-a phase plug mod?

-coolant tests?

For NSB;

It's a paper cone so you can use chemicals to coat the paper. Some people use

certain diluted glue, some used polyurethance, I prefer spray can lacquer cause

it's thinned and lacquer layers meld with each other. I used a 1" paint brush to

paint the cone and dust cap, but not surround as it was rubber. Four - six coats

worked, let dry between coats. I did progressive coats and listened to the driver

and did blind testing to find the sweet spot on how many coats were needed.

Phase plug in this case was cutting out the dust cap and getting a $1.5 rocket

nose cone that fix inside, but it's hard to get a cone perfect so I got one with

a slightly larger diameter and used the drill to behave like a lathe, using sand

paper the diameter was taked down in thickness. Balsa wood is soft, each to

work with. It's too soft, touching the cone would cause a depression, so

I used minwax wood hardener and soaked the wood a few times. After it dries,

I cut the cone base to desired length. Paint it if you wish. To attach the phase

plug to the driver, you insert a flat head wood screw on the base, countersink.

The magnetism will hold the lightweight plug in place. Ideally, a phase plug would

be nicer if machined out of metal so it can act as a heatsink for the driver to

boost power handling a bit.

Coolant tests were ferrofluid injections. But the Ferrofluid I snagged was the

wrong kind for $30 a bottle. I needed the oil base, not water base fluid, but

that stuff cost $100. So, I added motor oil to the fluid. Power handling is

amazing with this stuff. Oddly enough, when 16 NSB's were used in the array,

driven by the 1200w, they handled the torture well and no coolant mod was

needed. I could add coolant if I wanted to make a line array for the sole purpose

of torture by allowing more SPL driven by a bigger amp. I was able to generate

insane midrange SPL with one driver with coolant, at 10 feet away one driver

would kill the normal person, imagine an array with coolant and more watts.

I don't think I would be doing cone treatments, phase plug mods and coolant

mods on $150 drivers.. /hehe

 

[jaygeorge1979 10+ year member]

i think the only thing i would attempt would be cone treatments....seems cheap and easy enough, but how exactly does it affect the way the speaker produces sound?

PS i think i found my first project...my dad wants a line array...he likes stuff loud, SQ isnt TOO big of an issue, he just wants some new speakers for his big screen TV....it is gonna be run off of a mini system type thing, wattage unknown as of now...ill post up a new thread when i am sure i am gonna get it going...

 

[thylantyr 10+ year member]

i think the only thing i would attempt would be cone treatments....seems cheap and easy enough, but how exactly does it affect the way the speaker produces sound?

Manufacturers spend alot of time making cone material and/or treatments, so

there is aot of testing done I would imagine. You do something, measure,

listen during driver development. But sometimes I wonder if manufacturers

really listen because the exotic cone materials the marketing people brag about

don't sound as good as they claim. My favorite sounding midranges are treated

paper, not those esoteric materials that create worse sound gremlins that you

have to fix electrically.

When you do your own mods you do controlled tests. Do a mod, listen. Compare

to an unmodded driver. Ideally, a switch to allow blind testing with a friend or two.

 

[thylantyr 10+ year member]

PS i think i found my first project...my dad wants a line array...he likes stuff loud, SQ isnt TOO big of an issue

Assuming two channel tower;

Define a driver only budget and cabinet height....

 

[jaygeorge1979 10+ year member]

for drivers i am really hoping that partsexpress.com gets some more NSBs or at least a similary cheap driver, cuz i have heard good thigns about those projects....it is a two channel stereo....cabinet hieght isnt too important, but the TV is a big screen that stands about 5 ft high...so i would like em kinda tall...