[cosaw]

Hello all,

Wasn't too sure where to post this querry but seeing as active filters are more commonly implemented in active subs I thought I'd put it here.

I'll be building active crossovers for my diy subs. Question is can anyone suggest inexpensive active filter design books. Preferably with info on how to power the things.

I've found this one:
http://www.maplin.co.uk/Module.aspx?...dID=&doy=14m10

Has anyone had experience with this book? Are there better ones at similar price?

Note: If a moderator can think of a better place to put this post then that's ok by me.

Many thanks,

Simon

[GaryG]

You might find this link useful:

http://sound.westhost.com/project09.htm

[hornydragon]

£3.99 is a very cheap book mine average £30 mate.......... (the ones i buy not write btw)

[Ian J]

As we have a fairly active DIY section I will transfer the thread there for you although Gary has probably answered the question already

[cosaw]

Gary: thanks for the link, I have actually been looking at this site but a sub link from the link you provided has lead me to the power supply design which is what I need to learn more about. Thanks for pointing me in the right direction!

Hornydragon: you've got a point on price and I'm sure it's excelent value for money, I just wondered if anyone could recomend the content.

Ian: Thanks for putting this post somewhere more suitable.

Anyone else any ideas on books?

Simon

[GaryG]

Simon

I presume you've dismissed a commercial unit.


http://www.bkelec.com/diy/sbp.htm

http://www.williamshart.com/subwoofer.htm

[cosaw]

Hi Gary,

I'm open to all ideas however I'm trying to keep the price down this is why I was going the diy route. I'm going to keep it as simple as possible and only add further functionality as it is needed. I'm wanting to improve my understanding of general electronics so this is also an incentive. I'll take a gander at the links as I like to keep all options open.

Thanks again,

Simon

[hornydragon]

unless you have PCB production facility an off the shelf module will work out cheaper...... PS I am going to working on a CPLD implemented Filter ( ie download fileter on to a chip and can vary filter properties in software but its probably gonna take me 6 months and wont know till then if it is suitable for subwoofer.

Originally Posted by hornydragon

unless you have PCB production facility an off the shelf module will work out cheaper...... PS I am going to working on a CPLD implemented Filter ( ie download fileter on to a chip and can vary filter properties in software but its probably gonna take me 6 months and wont know till then if it is suitable for subwoofer.

Many people do fine on breadboards and op-amps for active filters. Here's a couple of useful links.

http://www.snippets.org/filters/crossover.htm

I think this site is old now, he never answered my e-mails, but a good read.

http://web.archive.org/web/200306121...nkwitzlab.com/

The whole site is a good read

I bought this book btw,

http://www.amazon.co.uk/exec/obidos/...384197-1662204

Try amazon for a used copy?

hth,

Rob

[cosaw]

Hornydragon I hear what your saying and don't really want to get too indepth with PCBs. I'm happy to use some sort of prototyping stripboard or breadboard.

Rob thanks for those links, this is the sort of stuff I'm looking for. May also try and look for some secondhand books as you suggested. It's like with anything on the net - plenty of information but when you tie it all together there are always a few holes which you can't seem to fill in by yourself which is quite often where a book helps.

Cheers,

Simon

[hornydragon]

prototyping on breadboard is fine but are you gonna put a bread board in your sub? I have PCB prototyping and Design and Layout software as well as simulation tools at my disposal...... So i guess i look at things from a different point of view...

Hey at least we know who to bother when we want a pcb made up now


btw just because the crossover is active, doesn't mean it has to go inside the sub enclosure.

Cheers,

Rob

btw cosaw, the Rod Elliot power supply that is on the esp site that Garyg posted is a good start for op-amp based xo's. I've got a built board sitting on my bench in front of me, waiting for my next project. Rod's boards are good value imo..

[avanzato]

IIRC Falcon Acoustics had a book or two on active filters.

[cosaw]

Hornydragon:

So i guess i look at things from a different point of view...

I don't think that's necessarily so. I'd love the more specialist tools that you have at your disposal. However at the moment budget just won't allow. This is my first hi-fi project and we've all got to start somewhere. I'm aiming at fairly high fidelity through more traditional techniqes in order to keep the cost down.

prototyping on breadboard is fine but are you gonna put a bread board in your sub?

The subs are in effect going to be totally passive: a box, a driver, input terminals. All the electronics are going to be externally boxed neatly. This way I can keep things nice and flexible.

Rob: Yes there is a very nice selection of projects on the ESP and it was this power supply I was looking at. Rob you live in the UK don't you? Have you purchased Rods PCBs/what are the shipping costs like? If not what do you use? The breadboards do seem a bit bulky but Maplin do stripboard which I was thinking of using although it does seem a bit more expensive:

http://www.maplin.co.uk/Search.aspx?...ria=stripboard
http://www.maplin.co.uk/Search.aspx?...oard&doy=17m10

Where is the best place to purchase these prototyping boards? Also do you know of a good 15v transformer/again what do you use?

Yes, sorry, more questions but you seem to be like the guy in the know. The more quickly I learn the quicker I can get these Sivas up and running

Many thanks,

Simon

[cosaw]

Avanzato: Thanks I'll check out Falcon Acoustics.

Simon

Hi Simon,

I ordered the power supply and a pair of of the linkwitz xo boards (2x p09) back in Aug 2002, and it came to 78 Aus$ which was about £20 ish if my memrory of exchange rates is right. The boards are light so the postage is small.

I never used the xo boards - would they be any use to you?

Try e-mailing Rod. He was very quick to answer me, and I'm sure would be happy to give you some advice.

The power supply board runs off a 'wall wart' power supply. I bought mine from maplins.

I also get my stripboard from there. You could try RS components or Farnell too.

Cheers,

Rob

[hornydragon]

Simon even with an external box you still need to mount an secure all the components..... I have melted a few bread boards in my time and they smell terrible. from a safety factor as well as neatness i suggest you look at getting a PCB layout tool i have used a couple and there are some cheap/ shareware ones around.... simulation is the best way to test designs before you spend 3 weeks putting it together only to find its not what you expected and you dont know why..... getting it wrong is all part of the fun, but its knowing what went wrong that teaches you... like when i built a whole system without any +/- supplies to any of the IC's
http://www.electronicsworkbench.com/html/eduhom.html
there is a student demo available......

[cosaw]

Hi Rob,

That seems quite reasonable - the price of the PCBs. Thanks for the other details also they will certainly help me out when I come to purchase all the bits and pieces.

I never used the xo boards - would they be any use to you?

Thanks for the offer. I'm not currently going for a Linkwitz slope. However if my plans change and at that time you've still got the boards kicking around I'd be very interested as it will obviously save me some hassle. I'll have a look at the schematics and bare them in mind.

Bye for now,

Simon

[cosaw]

Hello Hornydragon,

I see your point, it would certainly be helpful to test the circuit design before building. Thanks for the link I'll look into the software! What I'll probably do then is - simulate the relevant circuits forget the breadboards and then go straight to stripboard. If I decide that I'm going to need to build more projects than I'm currently thinking about I'll probably look into making my own PCBs.

Many thanks for your advice,

Simon