Want to start DIY Speaker

[maxxoverclocker]

alright right now i'll admit that im a DIY noob and have never worked with building speakers before. right now my experiance is with recievers and speakers, got a sherwood 210 watt reciever hooked up to 2 JBL N28's and another sherwood hooked up to 2 Pioneer SH153's and a 15" Audiosource Sub and all of these are hooked up to my pc right now. what im trying to do is make a single speaker that will serve dj like purposes but only in the sense that it will be mobile, i want to be able to hook up rca connections to it and want it to have higher than average audio quality. right now im in the VERY basic stages of designing it and may have some not possible/stupid ideas lol. one of those ideas is to have a reciever built into the speaker and im wondering if this works or will i have any concerns with this.

heres what i was thinking about as far as layout (but then again correct me as i havn't built my own and don't know about tuning and such)
http://prochaskagalleries.com/randompics/diyplans.gif

These are the parts that were in the plans
15" Sub (http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=290-155)
8" Subs (http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=290-055)
Midrange (http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=280-240)
Tweeter (http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=264-520)
Reciever (http://www.circuitcity.com/ssm/Onkyo-Surround-Sound-Receiver-TX-SR602-/sem/rpsm/oid/97895/rpem/ccd/productDetail.do) - not getting from circuit city lol

Questions:
*would it be smarter to have more or less drivers/tweeters
*will this even work
*will i need cooling for the reciever up top if this works
*how/can u tune a speaker like this
*will the sub portion need to be cut off from the rest

i think that about covers all of my thoughts and questions thanks in advance oh and could one of the almighty gurus on diy post a sticky for what you need to know to start doing diy speakers/subs? thx

[Ryan T]

Maxxoverclocker,

Sounds like an interesting project. There are a few things I'm a bit unclear on though. Are you looking for one big speaker or are you gonna make a few of them? I guess what threw me off was the 7.1 receiver.


The design may work but there are a few things that I think can be done differently and give you much better results. First off I would be worried about the receiver. Speaker enclosures (especially sub enclosures) vibrate. I wouldnt want a receiver sitting on the enclosure. It may rattle something loose over time etc.


The other problem would be enclosure size. With those drivers you would really need to have the 8"ers in a seperate compartment from the 15". That 15" driver alone would like a ~7 cu ft enlcosure. You could take it down to around 4 cu ft enclosure and tune it to around 20 hz but you wouldnt get hardly any response below 50 Hz.

Another big issue is the number of drivers. Most simple 2 way speakers are hard enough to get right but making a 4 way would be somewhat of a challenge. The crossover alone would cost a very pretty penny and you would really need some good test equipment and spend a lot of time using a program like speaker workshop to get it right. In the end you could save yourself a lot of trouble by going with a good 2 way speaker. I know it isnt as fun as having a HUGE 4 way speaker but in terms of sound quality a 2 way will be much better. If SPL and sound quality are a big concern I would highly recommend checking out the Adire HE 10 and 12 kits. They use coaxial 10" and 12" woofer/compression tweeter drivers. They are very efficient and the crossover design is already done for you :thup: .


The reason I'm stressing the crossover design is because that is what really makes or breaks a speaker. You can have the best drivers in the world and if you match them with a poorly designed crossover the speakers will sound bad. Unfortunatly the crossover is the most important (in my opinion) and the most difficult to get right. You have to measure each driver and build a crossover specifically for it. When your working with a 4 way speaker that equals a LOT of crossover leg work. It would be a tough project even for an experienced speaker builder.


For any speaker you tune it by placing a port in the enclosure. The frequincy at which the enclosure will be tuned to depends on the size of the enclosure, the diameter of the port, and the lenght of the port. There is a nice little program called winISD that will do the calculations for you. you just have to have alittle bit of working knowledge of how to use the program (its really easy once you get started).


I dunno if I qualify as an almighty guru but I'll start working on a tutorial about speaker/subwoofer design. To be honest I'm just really getting started on real speaker deisgn but I've done my fair share of subwoofers in the past :D. Anyway if I think its something that would be of use to anyone I'll post it.




Ryan

[maxxoverclocker]

alright thanks alot ryan lol so far u count as an almighty guru. first what i wanted to do was have the reciever actually mounted into the cabinet of the speaker (with its own little section). and i do want this to be simple so your saying keep it down to the 15 and a tweeter? or are you saying that i should keep it down to 2 different speaker types? im a little confused on that. Also, the 15" will have its own amplifier, what im thinking of doing is have the input go to the reciever and then the output going to the "amp" speakers and then a rca output going to the sub, so the volume will go up incrementaly but i won't have to deal with the 15" sub's crossovers. If i were to do this, could i get away with having the 15, the two 8's and the tweeter and only have a 2-way crossover?

edit: also it will be one speaker with (if it works) the 7.1 receiver powering the dual 8's and the tweeter with the sub having its own amp


thanks for all your help

[Korndog]

OoOo..only one 5.25" for midrange?

[Ryan T]

Have you checked out any stereo receivers with subwoofer pre outs? You should be able to get a decent stereo receiver for much cheaper than a HT receiver.

I think the best design you could do would be a 2 way with a subwoofer. you have to pick drivers that will play low enough and high enough to be crossed over. That 15" will not play up to 3500 Hz. If the speaker is going to be for PA use I would look at a compression tweeter and a good 15" pa driver. something like these.

http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=264-225
http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=264-308

http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=290-454

Those should be able to be crossed over around 2 kHz and one or two of those 15"ers would give you plenty of bass and will play high enough to crossover with the compression tweeter. But anyway I would consider something using PA drivers (dosent have to be the ones I linked). Still the hardest part is the crossover. Thats why I encourage you to go with something like the HE 12's since they have the crossover already done. It takes a ton of time and money to build a really solid crossover. I'm just breaking into that area of speaker design and I had to spend $140 on some test gear. On top of that I'm trying to learn speaker workshop (which is a somewhat difficult speaker design program). With subwoofers the design is fairly straight forward but with speakers it is much much more complicated.


You also mentioned you wanted something with above average sound quality. Are you refering to something better than the JBL N28 speakers you own?


Ryan