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dijaam 14th January 2013 03:00 PM

Noob building his first speaker
 
Hey guys, great resource this site is!

Basically I'm trying to build a speaker for a bit of fun and obviously to use if all goes well and it sounds good (ha!). Honestly, I've only lurked this site for a couple of days but got excited and decided I'd just get stuck into it, hopefully with some guidance everything will end well or at least I would have learnt something :)

So far I've followed this guide and built a crossover for some jaycar speakers (response 8" woofer, 25mm titanium tweeter ***are these even a good pair?***) for a crossover frequency of 2000Hz. I plugged it in to my amp and it works and actually sounded alright (lacked real bass but didnt have an enclosure, just a test).

I was really hoping I could get some feedback on the crossover if I listed the parts I used or posted a picture. Seeing as the crossover is crucial I want to get it right and although mine currently works, to me it seems to be a pretty basic build having followed a 'beginners' guide (it might be fine, i just dont know!) and so theres probably room for improvement.

Before I get to into enclosure design (or will this also have an affect the crossover design?) I want to get all the electronics sorted and hopefully jaycar bits will allow me to build something decent.

I hope I'm not being too much of a pain asking btw :)

Cheers.

sreten 14th January 2013 03:30 PM

Hi,

The links below cover the process in more detail than that guide
and put less emphasis on zobelling and more on proper modelling

rgds, sreten.

tvrgeek 14th January 2013 10:35 PM

I see sreten forgot the links. He has good ones, so I won't go there.

Just a perspective: They call these "loudspeaker systems" for a reason. The drivers, crossover, and cabinet are all inter-related. For that matter the room is too. You can't really understand or design one part at a time. Believe it or not, the radius of the front baffle can effect the choice of components in the crossover. Yes the radius. Add driver placement and dimensions to the equation.

I recommend building an established simple design. Let the forum members here help you understand why it was designed the way it was. Go through understanding measurements and beginning to measure them yourself. You will get much better satisfaction the more you learn. Better speakers too. Then you can start second guessing the design, changing the cabinet, changing the crossover, until eventually you are designing for yourself.

sreten 14th January 2013 10:48 PM

oops, rgds, sreten.

http://sites.google.com/site/undefinition/diy
(see if nothing else, the excellent FAQs)
The Speaker Building Bible
Zaph|Audio
Zaph|Audio - ZA5 Speaker Designs with ZA14W08 woofer and Vifa DQ25SC16-04 tweeter
FRD Consortium tools guide
http://web.archive.org/web/200909021...esigningXO.htm
RJB Audio Projects
http://web.archive.org/web/200909022...ve99/Spkrbldg/
Speaker Design Works
http://www.htguide.com/forum/showthread.php4?t=28655
A Speaker project
DIY Loudspeakers
Humble Homemade Hifi
Quarter Wavelength Loudspeaker Design
Pi Speakers - unmatched quality and state-of-the-art performance
The Frugal-Horns Site -- High Performance, Low Cost DIY Horn Designs
6.283 Audio Pages
Linkwitz Lab - Loudspeaker Design
Music and Design

Great free SPICE Emulator : SPICE-Based Analog Simulation Program - TINA-TI - TI Software Folder

PeteMcK 14th January 2013 10:57 PM

re:" ***are these even a good pair?***" - Jaycar drivers usually aren't very good quality, for not much extra money there are better alternatives, Wavecor, Visaton from Soundlabs Group; SB, Peerless, Vifa from Wagner or Essential Audio; Unfortunately there is now no local SEAS distributor, but they're still good value even if you have to import them from Madisound

re:"will this also have an affect the crossover design?" - enclosure width affects baffle step, which is often compensated for in the crossover

Moondog55 14th January 2013 11:06 PM

Jaycar are not as speaker builder friendly as they were a dozen years ago.
Try

SpeakerBug, capacitors, inductors, resistors, crossover parts, speaker supplies

Which woofers?
An 8 inch is starting to become difficult to cross to a cheap tweeter as most cheap tweeters need to be crossed quite a bit higher than the ideal XO point for a big woofer.
tvrgeek is right on the money. you need to design the whole thing together, so deciding on the box type and box size is part of that process.
I just checked the Jaycar website and I can't see the TS data for the tweeter but I imagine the Fs ( resonant frequency ) of the tweeter is around 1200/1500 Hz so normal usage suggests crossing over at least two octaves higher than that, around 4 or 5k and 2500/3000 if using a second order XO at a minimum although these rules are often broken it is a good starting point when beginning.

dijaam 15th January 2013 12:58 AM

Thanks for the replies! I thought it might have been too much seeing as
I'm essentially asking to be schooled on speaker design haha, a lot of forums arnt as nice.

Quote:

Originally Posted by sreten (Post 3325446)
Hi,

The links below cover the process in more detail than that guide and put less emphasis on zobelling and more on proper modelling

rgds, sreten.

Thanks, already in the first link I found something I'd be very interested in building (small 2-way floorstander) and I was hoping to build something like that with the parts I already bought for a budget lesson on speaker building. I have much more reading to do.

Quote:

Originally Posted by tvrgeek (Post 3326071)
I see sreten forgot the links. He has good ones, so I won't go there.

Just a perspective: They call these "loudspeaker systems" for a reason. The drivers, crossover, and cabinet are all inter-related. For that matter the room is too. You can't really understand or design one part at a time. Believe it or not, the radius of the front baffle can effect the choice of components in the crossover. Yes the radius. Add driver placement and dimensions to the equation.

I recommend building an established simple design. Let the forum members here help you understand why it was designed the way it was. Go through understanding measurements and beginning to measure them yourself. You will get much better satisfaction the more you learn. Better speakers too. Then you can start second guessing the design, changing the cabinet, changing the crossover, until eventually you are designing for yourself.

Fair enough, I was pretty aware everything would be completely interrelated but I guess I was more hoping for a quick fix and just build something for the sake of learning (I guess already have seeing as the crossover works, no idea where it ranks on sound though). The beginners crossover design guide made it seem so easy, and honestly it really was haha! Great article. Again, more research I suppose.

Quote:

Originally Posted by PeteMcK (Post 3326093)
re:" ***are these even a good pair?***" - Jaycar drivers usually aren't very good quality, for not much extra money there are better alternatives, Wavecor, Visaton from Soundlabs Group; SB, Peerless, Vifa from Wagner or Essential Audio; Unfortunately there is now no local SEAS distributor, but they're still good value even if you have to import them from Madisound

re:"will this also have an affect the crossover design?" - enclosure width affects baffle step, which is often compensated for in the crossover

Yeah I didnt expect much from jaycar, it was more the convenience of having everything I needed in one place to quickly throw some parts together and produce some sound. They even had blank 2-way crossover circuit boards with some more simple instructions on pairing resistors, inductors and capacitors, all I did was solder!

I was hoping to make a smallish sized floorstander (and hopefully build 2) and not need a dedicated subwoofer although I had doubts on whether jaycars woofer is capable. All a good bit of fun though.

Quote:

Originally Posted by Moondog55 (Post 3326109)
Jaycar are not as speaker builder friendly as they were a dozen years ago.
Try

SpeakerBug, capacitors, inductors, resistors, crossover parts, speaker supplies

Which woofers?
An 8 inch is starting to become difficult to cross to a cheap tweeter as most cheap tweeters need to be crossed quite a bit higher than the ideal XO point for a big woofer.
tvrgeek is right on the money. you need to design the whole thing together, so deciding on the box type and box size is part of that process.
I just checked the Jaycar website and I can't see the TS data for the tweeter but I imagine the Fs ( resonant frequency ) of the tweeter is around 1200/1500 Hz so normal usage suggests crossing over at least two octaves higher than that, around 4 or 5k and 2500/3000 if using a second order XO at a minimum although these rules are often broken it is a good starting point when beginning.

Yeah thats what I found searching around, apparently even the specs jaycar give on their current speakers are hit and miss :S. This only caused more problems because the specs they give lack a lot of info that all the design software needs to calculate box design.. way too much of an impulse buy I guess haha **could anyone suggest my best option still using the jaycar parts?**

I suspected that the tweeter might be a bit 'too' cheap. I guess jaycar sold premade 2-way crossovers at 3500kHz for a reason then, seems to be tuned for their tweeters. Problem is, the woofer was rated to 4.5kHz so is a crossover frequency of 3500kHz suitable if it should be a couple octaves lower? Maybe compromise at 3000kHz? How much will this even effect the system as a whole?


Thanks for taking the time to reply btw, very helpful! I guess I was hoping there was almost a shortcut for a quick build and just plug in a few numbers but it seems I lucked out (of course I could just build a quick box and be done with it but why not squeeze the best out of what I have). Probably best to stick with an existing design, I guess I just wanted the satisfaction of having build and designed 'everything' haha. Shame its much more complicated.

Thanks everyone!

PeteMcK 15th January 2013 02:15 AM

1 Attachment(s)
re:"**could anyone suggest my best option still using the jaycar parts?**" - Download ARTA, make a simple jig, & measure the driver parameters.
Download Unibox, type in the parameters & design the box,
Read up a bit on crossovers, & ask lots of questions here, & design a simple 2nd order LR crossover with some baffle step compensation built in.
It'll take a few weeks, but you'll be well on the way to being an expert.....;)

Moondog55 15th January 2013 02:29 AM

Read this thread too, as it has lots of information about the choices you need to think about making

http://www.diyaudio.com/forums/multi...r-project.html

Pete gave me a pair of those 8inch woofers a while ago, I'm of the opinion that they need to be crossed low, no higher than 400 or 500Hz. One thing you might consider is what is known as 2.5 Way speaker, pick a driver which has a good midrange reproduction and add a woofer using just a first order roll-off down low. I push this option rather than a dedicated 3-Way as it is much easier to get sounding OK without too much trial and error.
Where are you located??
What is your budget??
Other questions also need to be asked; such as how big is your room, how loud and which types of music do you listen to and is the room full of soft furniture or is it open and bare with hard wooden or tiled floors??
I would say tho that using that tweeter may make your job just a little harder and trying to match those 2 drivers without a midrange very hard indeed.

PeteMcK 15th January 2013 03:14 AM

ah...THOSE woofers... they're good for a bit of woof, but not much else...
(get a bit rough in the mids when you push them)
if I've got the model right, measured parameters (after burn in) will be approx:
Jaycar CW2196#1
Fs 37.00 Hz
Re 6.00 Ohm
Qms 2.38
Qes 0.32
Sd 187.0 cm2
Vas 36.5 l
Le 0.29 mH
I used them in pairs in 48L tuned to ~ 40 Hz (so 24 L for a single driver)


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