First time speaker builder (1 Viewer)

[Ryan Leemhuis]

I am interested in building a pair of bookshelf speakers for my first time. I was wonderinf if anyone could point out some reference material that would be helpful in learned all the details that are important to make good sounding speakers. I have the programs/spreadsheet unibox already. I am looking for more/better programs or just material that talks about how they work and how to build them

 

[GrahamT]

My advice is to head to the library and find some loudspeaker design books. Look for books by Vance Dickason, John Murphy and David Weems. I found them helpful. Good luck.

 

[Ryan Leemhuis]

Hey quick question, I was looking to use either dual 5.25 and a tweeter or a 6.5 and tweeter by Vifa. However, from the looks of it all of vifa's tweeters on partsexpress.com have a nominal impendence of 6 ohms...does this mean I can't use it for a 8 ohm system?

 

[GrahamT]

The impedance of the system is always the woofer. The tweeter impedance doesn't matter, it is treated seperately. I highly recommend that you dont try and design your own without measuring equipment. It is best to copy another proven design first and learn the basics. You will learn a lot and will be guaranteed a good result. I dont mean to discourage you, this was the advice given to me and I am glad I didn't waste my money and time.

If you give us your budget we can point you in the right direction.

 

[Ryan Leemhuis]

I have some speaker design software but I was looking to make a good bookshelf speaker to replace my HTiB dual 4" with 1 inch tweeters(HTB-505). I heard Vifa had a good reputation so I was looking at their drivers. budget wise would probably be between 200-400 for two. Basically, $100 for drivers for each speaker. Thanks for your help

 

[GrahamT]

$200 for drivers is pretty decent. Vifa does have a good reputation and they are very popular. Before you start to buy anything though read a couple of the books. The most important part of a speaker is the crossover, and finding the right drivers to use will help a lot.

 

[Ryan Leemhuis]

well I am studying to become an electrical engineer at Purdue University. So I wanted to do this from stratch to use some of my knowledge and have a fun time doing it too.

 

[Ryan Leemhuis]

I was looking at some of the pictures of the crossover's that are posted on this forum and I was wondering if there is "speaker" grade components or if I can order whatever I need for a company like jameco.com. Thanks for all your help.

Just as a side question. Would the VIFA D25ASG-05 1" Aluminum Tweeter and the VIFA P17SJ-00 6-1/2" make a good bookshelf combination? Would it be better to go for a dual 5.25 bookshelf?

 

[GrahamT]

We are in the same boat. I am going to start electrical or mechanical engineering in the fall and started learing this stuff for the same reasons as you.

The D25 and P17 look like good choices because they have extended smooth frequency response which makes your job easier. I am sure you could find a similar project on the net, the p17 is popular.

As for what is a better design, you have to decide based on what you want. Ideally you need to buy and measure the speakers (you can use speaker workshop). Then design the crossover. Think about zobels, baffle step compensation, desired efficiency, diffraction, driver spacing, lpad, crossover attenuation and type etc. Model it on the computer, build a test version, remeasure and tweak by ear then change components if needed. It is like and art, more than a science. Having so many reactive components all adding inductance, capacitance and resitance makes things had to predict.

There are speaker grade crossover components. Most people use low DCR air core inductors, non-polarized polypropene capacitors, and metal oxide or wire wound resistors.

I'm glad to answer your questions, people have been very patient with me here. I'm not an expert but I have made a lot of mistakes and can help you avoid making some of mine.

 

[Ryan Leemhuis]

Bot sure if I can use speaker workshop it says it requires windows 95. I don't have that, and it doesn't run the setup file.

Can anyone tell me if it would be better to do a dual 5.25 project instead of a 6.5?

 

[Brian Bunge]

IIRC, there are several designs using those very drivers and I know of a couple of retail products that use either those exact drivers or variations of them (Think PSB Stratus Minis and Stratus Golds).

 

[Ryan Leemhuis]

I am confused about a point. My speakers have ot be 8 ohms for my receiver. If I want a dual woofer+tweeter design....do I have to put the woofers in series with 4 ohm drivers!?

 

[GrahamT]

Yes, or 16 ohm woofers in parallel of course but these are rarer.

 

[Ryan Leemhuis]

I was told that I could run two 8 ohm drivers in series and still have it run fine on a receiver intended for 8 ohm nominal impedence. Is this true?

 

[GrahamT]

Depends. Two 8s in series as you know will produce a 16 ohm nominal load. This will be perfect for any receiver at low volumes because the current draw is low. The problem is that the maximum power available is now halved. The amp might clip the voltage signal when pushed.

 

[Ryan Leemhuis]

well I have 100 watts available per each channel. So would that be more than enough as I do play my music fairly loudly sometimes(not BLASTING but loud) Or should I stick with putting 2 4 ohm drivers in series?

 

[Ryan Leemhuis]

Another question....Is it bad to mix types of woofers? For instance, if I was to use a glass fibre cone 6.5" woofer and a 3.5 inch or any other type(paper, polypropylene) would that not sound right?

 

[Ryan Leemhuis]

I've done some reading, and I was wondering if a butterworth filter is generally the best type of crossover to use? Any answers to my previously unanswered questions would be much appreciated too

 

[GrahamT]

Well, IMO I think you should stick with one 6.5"

You can mix drivers made from different materials, but the more drivers you have, the more complex things get both acoustically and electrically.

Butterworths are popular, but the best crossover depends on the application. LR filters are very popular aswell. I cant tell you which to use.

 

[Mike_Bauer]

Ryan, think about your speakers electrically. What does the input current from your receiver "see" as it goes into the speaker? Tweeters, Woofers, etc are all transducers and have have impedance (Z) rather than resistance (R) however you can still safely use Ohm's law to figure everything out. Think of your transducers as a resistance and figure it out like that.

Answering your early question about speaker quality components. Look for the manufacturing specifications, i.e. the range of values. A 1% resistor. cap, coil, etc will have a lower range of variance than a 5 or 10% component. Conceivably with 10% components you can have a 20% difference with two components. I would think 5% components would be a nice balance between cost and quality, but 1% components are not too expensive.

My advice is to buy a kit or else be ready to experiment. Remember the components you choose will have a range of values. So you don't really know what the sweet spot for a driver is. Lets say you choose a 5 inch driver with a hypothetical frequency response of 40-4000 Hz. It will have a hypothetical sweet spot between 80 and 2000 Hz. So if you design a crossover to use its entire response it will give you and output but at the lower end it will roll off and have a low volume and and the upper end it may break up a bit as it can't handle the rapid transitions.

You could bread board a cross over and use a signal generator and an oscilloscope to see the output.

Keep it simple, remove variables, track each change, etc. A tweeter and a woofer and a standard cross over. Try it see what you think and then build a better one.

an aging E.E