Got a Crazy Sub Idea

[drew spelts]

Ok what if you take a monitor 60 or monitor 70 floor standing speaker and replace all the woofers with these http://www.partsexpress.com/pe/showd...number=264-832. Then add an amp and boom you have tower subwoofers that look just as cool as some Rti 10's or 12's. I am wanting any thoughts or criticism.

[RuSsMaN]

I think you should do it. PLEASE do it.

[BIZILL]

now, russ.........

[bobman1235]

At least he prefaced it with the crazy idea warning....

[PolknPepsi]

Really,
I dare you......no, I double dare you....then post pictures and let us know how it sounds.

[drew spelts]

Ok, its a deal, I am very curious also but I need help finding a good deal on some monitor 60's preferably 70's that may have blown woofers or burnt crossovers or non cosmetic damage to the enclosure so that I can do this. If all of you guys can help keep an eye out for me on this stuff I promise to do this and take some sweet pics and write a review. I plan on using a 1000W amp per cabinet i hope that will be enough. Please help me out on this dire mission.

[RuSsMaN]

Ok man, rock on!!! Can't wait for the 'sweet pics'.

[VR3]

make sure those holes are big enough to mount them...

Or surgery will be what your doing.

[dorokusai]

You ever take that speaker off some sweet jumps?

[michael_w]

it'll get like 3 feet of air...

[drew spelts]

ok I just got off the phone with Circuit City today around noon. I was calling them because I thought that I saw some monitor 70's on clearance over there or something a couple weeks back. The sales associate that I talked to said that He had one "odd-ball" Monitor 70 in their display room that was an open box item. He said that it is reg. $399.99 but he is trying to get rid of this one and could sell it for $199.97. he also said that the price is cheaper than what they buy them for which I find EXTREMELY hard to believe. So, is this an ok deal or should I go in there and offer $150 take it or leave it.

[unc2701]

Ok, someone's gotta ruin the fun before he wastes $150 on a monitor 70 and $160 on drivers...

Drew: That's a horrible idea.
1) Drivers require a certain air mass in the cabinet to operate properly. Some drivers work well is a sealed cabinet, some better in a ported cabinet. You can summarize a driver's properties with what are called the T/S parameters. It would be a stupendous coincidence if the monitor 70's drivers had the same T/S figures as those tang-band ones.
2) You're $310 in without an amp or a crossover. The 1000 watt plate amp you want is $400. You can do better for $700.
3) Those drivers will have usable response down to about 40hz in a ported cabinet. Which is exactly what the response is on the monitor 70. Four of those drivers will handle 200 watts RMS. The monitor 70 will handle 275 watts. You'd be better off yanking out the crossover on the monitor 70 and wiring the four midbass drivers up series-parrallel to your plate amp.

Building subwoofers is far easier than building fullrange speakers, but you gotta do SOME research into how to do it properly.

[bobman1235]

Awww, way to ruin the fun :)

[unc2701]

I couldn't let him do that to a good speaker....

[PolknPepsi]

I was serious.........just didn't know if it could be done for a couple hundred bucks. When it starts costing a few hundred then you are talking SVS territory.

[drew spelts]

Well crap I was thinking it would be a "fairly" good idea, I guess not. Thanks for letting me know before I blow a ton of dough. And to all you guys that knew it was a bad Idea from the get go, well thanks for not warning me, but its ok, absolutely no harm done. LOL. I was seriously hoping I could make that thing go to about 25hz but now it seems as though that might be an impossible number to reach. Perhaps this is due to the speakers being too small. I am very interested in building my own sub but I definately do not want to use speakers larger than 12" Preferably several 8". Any advice would be greatly appriciated.

[VR3]

My first advice...

Is to not use any OEM enclosure. Especially ones that currently do not have any subwoofers in them.

Building a sub involves carefully configured enclosure volumes, port width and lengths and a nice powerful amp.

[Early B.]

If you wanna build your own subwoofer, go for it. Plenty of fellas have done it. It's lots of fun and you'll learn a lot. Google "DIY subwoofer" and get to learnin'. Also do the same search on this forum. Read everything you can in the Tweaks and Mods section of this forum, and ask lots of questions.

BTW, I like your concept of a "floorstanding subwoofer." Try DIY dual double stacks with 12" or 15" woofers. Call them the "Pamela Andersons." Heee Heee Heee.

[drew spelts]

I'm thinking along the lines of at least a triple stack to give it the height look that I want. Most likely 8's but definately no bigger than 12's. thanks for the search advice in this forum. I have done about as much as possible on google.

[Early B.]

Forget about using 8's. If you're gonna build your own killer sub for HT duty, use at least 12's. Also the stacking thing sounds pretty cool, but ya gotta be realistic. I was sorta joking about that. Consider size, weight and aesthetics. And if you have a woman around, you can forget about it altogether. Once again, take some time and do your research.

[unc2701]

I've never heard an 8" that could get under 30hz with any authority... You'll need at least a 10" and you'll have to search to find one that really digs deep. Also, you'll want the number of drivers to be powers of 2. Otherwise, you'll get weird impedences.

[michael_w]

You could do something like that guy from force audio did (can't remember his name bah). He put something like eight RE 8's into a giant box and managed to hit around 142 dB with under 150 watts. That was for a car but I'm sure if you tuned it right you could tone down the spl and make em dig deep.

[unc2701]

OK, I just found a 8" with an Fs of 23 hz:
http://www.madisound.com/cgi-bin/ind...15933&pid=1041

It'll work in a sealed box, but they recommend a qb3 alignment, if you want to try that. Not a lot of spl or wattage, but it'll dig deep and a ported box will under a cubic foot.

[michael_w]

Here was what I was talking about... my numbers were close but still off by a bit.

RE 8 build by 95honda

[audiobliss]

I'm glad to see someone broke the news to him before he spent his hard-earned money on a Monitor 70. I can't believe y'all egged him on like that.

drew spelts - Sounds like a very interesting idea you have for a 'tower sub' and, as others have said, it's possible but it'll require more work than just replacing the drivers in a tower speaker. You'll have to build your own enclosure based on the requirements of the drivers you're using, which you'll decide to use based on lots of research. Hope it turns out well for you. If not, then I hope the process is a lot of fun.



On a side note, I recently got an idea about subs. I was thinking about SVS's cylinder subs and how they're ported. Don't they have the driver mounted at the bottom of the cylinder firing up into the tube and then a port on top? What if you chose a passive radiator based on the volume of the cylinder and replaced the port with the passive radiator so as to create a sealed enclosure (I think there's a term for a sealed enclosure that uses a PR, but I can't remember what it is)?

Just an idea that I had, and I wondered if it'd be worth anything.

[unc2701]

PR's are almost always sealed... anyhow, just about every sub design, pros & cons are covered here:
http://www.danmarx.org/audioinnovation/theories.html
(good link to save)

[drew spelts]

Scraping the whole build it on your own idea right now because if it costs over $500 its out of the question. I have also done literaly an ASS load of research on all used subs and have come to one that is very provocative. It is made by NHT "Now Hear This" it is called the Sub Two it has two 10" drivers and has good numbers and way above average reviews, plus the remote for this unit is completely detached so you can have it with your equipment instead of looking behind the sub to do adjustments. Another, most likely more expensive option is the Sub Twoi it features two 12" drivers and all the other same stuff as previously mentioned. I am asking for your opinions on this thing being used for HT.

[unc2701]

NHT is pretty well respected, but not particularly well-known for its subs. The exception being the 1259 driver, which is a favorite of DIYers. I haven't heard the sub two, but given that it's a sealed box, you can expect tight responsive bass, at the cost of SPL's. Probably more of a music sub than a HT sub.

As an aside, www.madisound.com has 10" NHT drivers on sale for $75, with a dual ported plan that should be pretty easy to assemble (and doesn't require any thought on your part). Throw in a plate amp (or any old power amp if you've got a crossover sub output on your AVR) and you're good to go.

[Early B.]

Scraping the whole build it on your own idea right now because if it costs over $500 its out of the question.

It's fine if you decide to scrap the idea, but cost is one of the main reasons for DIY!! For less than $500 you can build an awesome sub. Assuming you already have basic tools, the budget would look something like this:

12" or 15" Driver -- $150
Amp -- $125
MDF -- $50 (six 2' x 4' sheets @ $8/ea.)
Misc. -- $75 (port(s), wood glue, screws, polyfill, paint, etc.)
TOTAL: $400

Do some more research.

[drew spelts]

Thanks so freaken much "unc" wow I had no Idea this site existed and i searched alot on google. wow I am thinking it just might be worth it to do it on my own again with two 12" I could have a really tall box with the necessary 3.5 cubic foot needed per speaker. Thanks everyone. I will keep you posted.