Newbie Kids Project

[Q45]

I know this is the bass-ackwards way of starting a speaker project, but I gave up a speaker upgrade project on my car cuz I found out I have a Bose system that is pretty good and I just no longer have the patience or the back & neck muscles to F with cars.

So subsequently I am returning some speakers but can only exchange. The closest thing I can find to something that can be used in home speakers from this on-line co. is some Cerwin Vega HED 8.4 - 8" DVC 4-ohm Sub-woofers.

My 14yr old has expressed sudden interest in electronics. I am an electrician by trade and have also built some bad-ass towers a few years back.

I want to build some basic bookshelf 3-ways with my kid just to kind of get him into it and to ease my wife slowly into the sudden expenses. Just between us, I do plan to start to get back into bilding my own gear.

I want to buy some basic empty boxes, hopefully from someone on this forum, and I want to use the Cerwin Vega's to start for the woofers. I'll get the mids, tweet's & X-overs soon.

Does anyone see any issue with going ahead with the exchange and picking up the Cerwin Vega's? I can always accomodate boxes & X-overs to get close to these subs. It's just a starter project with my kid. He won't know the difference.

Feedback?
Boxes for sale?

[tf1216]

My gut tells me to suggest for you to search Parts Expres and different forums for finished speaker projects. Both Parts Express and Madisound sell finished cabinets that are suitable for many finished designs that can be found on the web.

You may not have your expectations set too high and want to keep the Cerwin Vega drivers and find a tweeter to mate with them. Then build a text book high pass and low pass crossover and call it a day. If that is the case, Parts Express has everything you will need.

[---k---]

Building decent speakers is more than just putting a driver into a box. The crossover is likely the most difficult and critical parts to a speaker. The stock crossovers that you can buy from places like Parts Express are marginal. For info on what goes into designing a good speaker, take a look at the mission Accomplished projects.

To avoid being unsatisfied with what you build, we generally recommend building a proved design from a site such as this, zaphaudio.com or a few others sites. But, since your stuck with only being able to exchange, it makes things difficult.

The first thing you have to identify is whether you can get all the T/S parameter for that driver to model it. Without, you're really doing things blind. But, if it is just for your kid to play with.... We just would hate for DIY to leave a bad taste in his mouth.

[Q45]

Building decent speakers is more than just putting a driver into a box. The crossover is likely the most difficult and critical parts to a speaker. The stock crossovers that you can buy from places like Parts Express are marginal. For info on what goes into designing a good speaker, take a look at the mission Accomplished projects.

To avoid being unsatisfied with what you build, we generally recommend building a proved design from a site such as this, zaphaudio.com or a few others sites. But, since your stuck with only being able to exchange, it makes things difficult.

The first thing you have to identify is whether you can get all the T/S parameter for that driver to model it. Without, you're really doing things blind. But, if it is just for your kid to play with.... We just would hate for DIY to leave a bad taste in his mouth.

Not to worry about that. I built a couple of towers a few years ago, with my own crossovers and own cabinet design.

It was a very long and drawn out process and after doing the math I quickly determined that I probably could have bought a high grade pair in the store for less. But I was actually quite surprised with the outcome. They sounded incredible and I actually ended up selling them to a client I was wiring a custom home for, who was not happy with some Paradigm's he spent like $2500 on. He liked mine better.

In short. I know I can do it. This is just a starter kit for my kid to get into.
And I've actually had great luck with Cerwin Vega woofers. Onlinecarstereo.com doesn't have much else that could be useful in home speaker building.

I'll match the tweeter and X-over later. I just wanted to see if there was anything anyone knew that I might have been overlooking.

Thanks

[Operandi]

If your set on using those car subs I think the best idea might be to make bass bins out of them and go with a small two-way speaker to go along with them.

You could either make them separate cabinets or build them as one with an internal partition. You could also integrate a plate amp into each speaker to power the sub.

[Q45]

If your set on using those car subs I think the best idea might be to make bass bins out of them and go with a small two-way speaker to go along with them.

You could either make them separate cabinets or build them as one with an internal partition. You could also integrate a plate amp into each speaker to power the sub.

Wow, I'm already getting picked on, look at that.

"Car subs". Well, I guess they maybe classified as "Car Subs" but the spec's. speak for themselves and honestly in my newbie I guess car audio guy's opinion, they're not a whole lot different from the spec's. on some of the Dayton "Home Subs" I've reviewed.

If I can control the install of electrical and tech systems in a skyscraper, I can build some low budget speakers using "Car Subs".

[ThomasW]

Wow, I'm already getting picked on, look at that.

"Car subs". Well, I guess they maybe classified as "Car Subs" but the spec's. speak for themselves and honestly in my newbie I guess car audio guy's opinion, they're not a whole lot different from the spec's. on some of the Dayton "Home Subs" I've reviewed.

If I can control the install of electrical and tech systems in a skyscraper, I can build some low budget speakers using "Car Subs".

First let's chill, no one is picking on you, and second no one said you "couldn't" build a speaker using car drivers.

On this forum we use a more technical approach to building speakers. It starts with measuring the performance of the drivers mounted in the intended baffle (this means both frequency response and impedance). This data is then imported into a crossover design program and a first pass (aka alpha) crossover is designed. That prototype is made and a new set of measurements are taken. The new data is then integrated into the crossover design. This process continues until the desired performance characteristics are achieved..

If you want or need an analogy think of this......

I want to wire my new house. Do I walk into a store that sells wire, conduit, junction boxes, circuit breakers, etc, then randomly pick and choose any mix of these items and start to work? Or is there a specific way the task should be approached to do it correctly?

Using a generic crossover and picking any random drivers to build a speaker is no different than the house wiring scenario I described above...

[Q45]

First let's chill, no one is picking on you, and second no one said you "couldn't" build a speaker using car drivers.

On this forum we use a more technical approach to building speakers. It starts with measuring the performance of the drivers mounted in the intended baffle (this means both frequency response and impedance). This data is then imported into a crossover design program and a first pass (aka alpha) crossover is designed. That prototype is made and a new set of measurements are taken. The new data is then integrated into the crossover design. This process continues until the desired performance characteristics are achieved..

If you want or need an analogy think of this......

I want to wire my new house. Do I walk into a store that sells wire, conduit, junction boxes, circuit breakers, etc, then randomly pick and choose any mix of these items and start to work? Or is there a specific way the task should be approached to do it correctly?

Using a generic crossover and picking any random drivers to build a speaker is no different than the house wiring scenario I described above...

I'm so chillin, I'm jell'n! Jell'n like Magellan!

I just like to get things riled up sometimes. Too many people are far too technical and take themselves far too seriously (myself many times included)and I just like to kid around, A LOT!

No worries mate!

So a cross-over?

That's those little wire thingies on the inside of the "Box" right? :T

[cjd]

The reason car subs matter is that they're generally not performant outside a narrower window of frequency, but are optimised for small-box + cabin gain. Saying "car sub" doesn't do anything other than call it out for what it is. If I tried using a "home sub" in a car, it would be no different.

But, asking the questions you're asking in this forum would be like me asking you if I can take some lamp cord and run an outlet over to the other side of the room. I'll get to the details of installing the outlet (maybe I'll just wrap the wire ends over the plug? ) and all that stuff later... Ok, so maybe the analogy is a little extreme. The answer is "yes you can" and "well, that's not necessarily the way to go" at the same time.

Most of us have probably forgotten what it's like to play around with this stuff and not care how it works out.

My suggestion would be to snag some cheap 3" or 4" drivers that are decent full range (Parts Express often has buyouts for a few bucks that meet this criteria) and plan to add woofer, tweeter, and crossover later. If you want to start single driver and build on from there.

C

edit: whoops. I hate being interrupted by work mid-post. Looks like Thomas and I had similar analogies too. heh.

edit edit: spelling

[Q45]

OK, for the record, I don't wire houses. I did early in my career, but I'm actually a coordinator of all technical trades in high-rise construction in the LA area.

But I appreciate the analogy.

I actually have started to comprise MY BOM for the towers I'm going to build. I'm going to try and re-create a cabinet design I did years ago that was great. I've spent a great deal of time looking through many of the designs you all have completed and I'll definitely be copying some things.

I'm just going to start slow with something small for my son, cuz if my wife new what I had in mind for the living room and the cost involved, she'd probably try to thwart it.

Gotta ease it in, ya know? Can't just ram it! The ideas & plans I mean!

I studied psycho-acoustics when I was younger and used to be really into speaker design and am very excited about getting back into this.

Looking over many of the designs here in this forum, I've seen things have changed a lot since I used to build 15 years ago, but the fundamentals like so many other things just never change and having an understanding of the fundy's is a great enabler to get back into things easily.

Thanks everyone.

[Q45]

Picked up the Cerwin Vega 8" woofers yesterday. WOW! These things are nice.

Came with all the spec's I'll need to start to put together dimensions for a cab.

Does anyone have a fairly simple equation format to enter in spec's to kinda get the ball rollin for X-over design and cab. dimensions?

I have the Keele's 4th edition or something like that, but honestly the calculations and equations are pretty tech and I suddenly feel like I perhaps should have read the 1st 3 editions first.

This is not my area of expertise. I usually deal with voltage parameters 480v and higher.

Just if someone has a simplified starting platform?

If not, I'll just wing-it. What's the worst that could happen?

[ThomasW]

Basically you have two options

1) use a generic crossover
2) Invest in measurement and test equipment, learn how to measure the performance of drivers in-baffle, then learn to use the software design programs for the creation of crossovers.

[Brian Bunge]

If you have Excel, do a google search for "Unibox". It's a freeware box design program that's very powerful and very accurate. I use it almost daily.

[Q45]

If you have Excel, do a google search for "Unibox". It's a freeware box design program that's very powerful and very accurate. I use it almost daily.

I actually stumbled upon that link within this forum somewhere, right before you responded.

Thanks.

[Nemophyle]

well just my 2 cents, you should listen to thomasW and cjds advices about crossover design.

Not only they're right, but coming here to ask something and then say "nah it's ok i'll handle myself" without listening is kind of impolite

i understand if you don't have the time/money to invest in something like test equipment. But starting with drivers you have no data on + no test equipment is like the silliest thing you can do , if your goal is sound quality of course.

if you're goal is just making speakers that produces sound, you should just buy a generic crossover and get started. But if that is your goal i have trouble understanding the aim of all your posts.

gday

[PoorboyMike]

well just my 2 cents, you should listen to thomasW and cjds advices about crossover design.

Not only they're right, but coming here to ask something and then say "nah it's ok i'll handle myself" without listening is kind of impolite

i understand if you don't have the time/money to invest in something like test equipment. But starting with drivers you have no data on + no test equipment is like the silliest thing you can do , if your goal is sound quality of course.

if you're goal is just making speakers that produces sound, you should just buy a generic crossover and get started. But if that is your goal i have trouble understanding the aim of all your posts.

gday

Don't take this as disrespectfull, because I see everyones point here, but he is trying to work with what he has to save money and at the same time, spend some quality time with his son. What's so bad about that? Is he going to get world class speakers? Probably not, but I'm pretty sure that is not his goal here.

I have a 12 and a 14 year old, so I know where he is coming from. Just finding something you can do together with your kid that you both enjoy is often more than enough. If his son truly does enjoy this project, they can invest more money and design something better down the road.

That's the way I see it anyway. :B

[---k---]

Most of us have probably forgotten what it's like to play around with this stuff and not care how it works out.

Agreed.

Have fun with your son, and look forward to doing it right some day.

[joecarrow]

Definitely- this sounds like a great time, and if I recall correctly, a lot of cerwin vega speakers have a lot of output potential. Whether or not they are the last word in sound quality, they ought to be popular with the intended demographic. This should be a good time, and not one to take too seriously.

If he wants to start planning new towers, then we can pick some nits

[dawaro]

One possible route you can take would be to use the Cerwin Vega subs in bass bins as mentioned before with a plate amp and build a smaller speaker to use for the upper range.
Here are a couple of projects you can look at for the satellite speakers:
ZBM4
Hi-Vi B3S

Both of these designs are very affordable and in a small package. The B3S design also outlines use with a plate amp.

This Dayton SA70 plate amp would work well for the subs.

Just my thoughts...

[Q45]

Wow, thanks everyone!

I've actually put a great deal of thought into this lately and I've decided to "86" the idea of buying a kit and instead I'm going to go out today and buy a table saw, router and that cool router guide for cutting perfect circular holes that I saw one o ya'll recommend from Parts Express.

I figure if I'm going to teach my kid something I might as well go all the way and teach him a bit about woodworking and basic problem solving as well.

And yes, finding something you and your kids both are interested in IS sometimes tough. I was an athlete in my younger days and still play professional racquetball at the age of 39 and my kid is about as far from an athlete as you can get. I was a rough-neck so to speak and been in construction my whole life. I don't think my kids ever even been in a fight let alone gotten a splinter.

So yeah, if he shows some interest I'm going to jump all over this.

Thanks for understanding and the feedback. I'll get into the larger, more involved projects after this one is done.

And no, saving money is not an issue. But I do like the idea of using the CW's possibly in a sub woofer box. I was actually thinking of that too. Thanks for the link!