Building a subwoofer: Help needed!

Neutrla,
can you be specific on what drivers you will be using ..
based on that we can start to design a sub enclosure type(closed, vented)...
Cheers,
Sachi

Hi Ben,

I am not yet at the design stage. I am at the information gathering stage where I am trying to learn as much about subwoofer making in India as possible.

I am considering using a single or double 10" driver in a vented enclosure for higher efficiency. (I thought 10" would be the right size since my bookshelves have 5" drivers.) I just want to put together the cabinet and a subsonic filter at around 27 Hz. Not looking at any amplification or crossovers at this stage.

At least can you point me to the drivers that you plan to use..

From what I heard, designing a sub which has proper extension which does not boom is not all that easy…………..A relatively cheap way out would be to import good kits. Check with Siva and Viren on the forum. They may have researched quite a bit on this. Remember that a boomy, badly designed sub can destroy whatever magic you get from your b/k speakers. Undisciplined bass is one of the biggest culprits for bad sound.
Alternatively you could ping Richard bass-nut-greene on http://www.audioasylum.com/audio/speakers/bbs.html This guy is just awesome with anything bass related and have decades of experience with subwoofers.
Here’s one sub he always recommends for max-bang for buck. http://www.partsexpr...&raid=37&rak=300-760
He recommends a Behringer Feedback Destroyer Pro with the sub http://www.behringer.com/DSP1124P/index.cfm?lang=ENG for advanced users. Here’s a mine-field of knowledge about subs and feedback from users and experimenters on the AVS forum. http://www.avsforum.com/avs-vb/archive/index.php/f-113-p-12.html
Hope this helps……….

I agree,
it is better to go the tried and tested way..spesially for subs..
The dayton(Titanic kits from partsexpress.com) is the most promising and VFM in my view..
Cheers,
Sachi

I'll check out the links. Then I will have a better idea as to what driver I need.

good links sq wave, very interesting.

Hey neutral,
Did you finally buy your bookshelf speakers ? If so, are you planing to augment the bass response of your high quality b/k speakers with the DIY sub ?

I only have economical bookshelves and matching power amplifier from Pulz. I enjoy listening to high quality stuff from Energy, Magnepan etc but can't afford them So I just check them out and post reviews for the benefit of other richer folks

Bookshelves can't produce much bass. So wanted to make a DIY sub to complement them in music and to add punch for DVD movies.

Some thoughts on this. Maybe it will help you make a decision.
First of all “good quality bass is expensive”. What you hear from budget subs is muddy bass or one note bass. There won’t be much detail in the bass notes. The bass notes will all sound more or less similar.Muddy bass can also result from high quality subs placed in bad rooms due to peaks and dips in the room. Now it depends on what you want to achieve with a sub. Some guys are not very particular about quality in the lower octaves. They just want to add some low-end energy especially during movies. If this is your motive, adding a budget/diy sub will help. If you are looking at good bass response which matches with your existing/future b/k speaker in detail, speed and quality, I would suggest you save up some more money and buy a good one like Rel, hsu, svs, infinity, adire, paradigm etc….Another thing is room treatment. More bass energy means more room problems. There is a good reason why people with normal rooms do not buy subs.Most rooms loaded with good subs need good treatment and parametric equalization to get obtain a listenable flat response. My speakers rated at 30hz + - 3db creates enough problems for me in my modestly sized untreated room. I shudder to think what a sub will do. It all depands on your priorities. Think about this carefully before you decide………maybe a good full range floor stander may be better for you rather than a quality b/k plus a boomy sub.

the other day i saw towers with side woofers-
and later i found quite a few companies making this design-

something like this
http://www.mordaunt-short.co.uk/products/avant908.html

say if one gets these , do you still require sub's?

regards
anirvan

say if one gets these , do you still require sub's?

One known person is using this MS908. Though he has big listening room, he felt bass was too much & was disturbing mids & highs. Surprisingly, he has disconnected the connection to bass driver & using only other drivers with which he is extremely happy. Try to audition. Good musical subs costs too much. IMO & as well some Sr audiophiles better combo is BS + musical Sub.

Such towers have the woofer mounted on the sides than the front baffle. It is basically the same as any other tower when it comes to frequency response. A sub is always a good idea even with a tower provided the sub is of similar quality as the tower and is capable of providing you with the extra extension from where your tower rolls off its bass response. I emphasize the word “extension”. Cheap subs just increase the volume (db) generally around the same frequency where the towers rolls off without giving you any actual extension. This gives you a false impression of bass. A sub should not call attention to itself. It should just fill in the missing lower octaves.

True.Sq..Even you 've good musical sub, it's not that easy to get it integrated with your floors. Placement of sub (though LF is non-directional) more critical than Flrs. One needs to experiment a lot.

Neutral> Hey! not to break your head too much by these postings. I could makeout you are looking for some lowest cost & decent sounding Sub, but you 've not got proper help

Thanks Square-wave,

I checked out some of your links. The Dayton sub from Parts Express looks good. But tell me - how does one get a 30kg monster into India? The shipping and customs cost will kill a middle class person

I was overwhelmed by the audioasylum and avsforum sites. It will take me at least a week to go through them!

Yes..that’s something to ponder about………customs and all that !!!
Subs and bass management is a vast field in itself. There are people who make a living out of bass management for HT and stereo. So just imagine! Building good subs is like building a good speaker. The frequency is very extreme and getting good disciplined and controlled bass with detail is no mean feat.
It all depends on you. Your room acoustics, budget and your immediate needs…. I just pointed you in the right direction so that you can take an educated decision. If you have a 20k budget, there is one good product which has been getting good reviews. The lithos sub. This guy specializes in a sub which causes minimum ear fatigue. He calls it “Q-Balance” I have not heard one. You could just check it out. I think it costs in the region of 20k. It may work out for you. This could be a cost effective solution if you do not want to go for a full range floor-stander.
http://www.lithosindia.com/Home.htm

Thanks Square-wave,

I have heard the Lithos sub a few months earlier at Observer's place. It uses a bandpass design and two 10" drivers in a passive sub powered by an external amplifier. It is discrete and doesn't call too much attention to itself.

I got the idea of building my own sub with two 10" drivers from this sub. But if I go the DIY route, it would have to be a much simpler design than this one.

Best of luck………..keep us posted…….

square wave, powersupply-

there are subs in the 15k range-
sonodyne, wharfedale, polk audio
where do these stand- good , average- vfm or ugly?

also if someone is building a decent sub -approximately how much would be cost?

regs
anirvan

Okay anirvan,
according to me the cost of a 'decent' sub would be..

1>2k to 4k for the driver
2>3k for the wood work and all
3>3k for a 120watts RMS paralleled LM4780(including PCb and
transformer)
4>another 1k for terminals and other unforseen expenditurers..

So for around 10k you should have a decent sub considering that you know how to design and build one..implementation is as important as designing, if not more..
As for your reference to budget subs..i felt polk audio was pretty okay for HT..definitely not for stereo though..also u may have to turn the gain pretty high to get things shakin..

benkenobi

at 10k Polk is a much better bet than most available in the market....but will not induce fire in you like what a DIY does

SUB_BOSS schrieb:

at 10k Polk is a much better bet than most available in the market....but will not induce fire in you like what a DIY does

I totally agree...
actually, i think it would be super to have one polk for every channel so taht every channel is full range...imagine that..

I wouldn’t touch these especially for music. For low budget HT applications where detail and musicality in the low octaves is not very important, these are ok. If I had only 15 to 20k to spend, I would be looking at something like the Lithos sub. Subs is a big industry now and every tom dick and Harry is cashing in on it. High level of ignorance about Bass in general makes it easy. Bose has been doing it for ages with their AM series with that one note mid-bass thumping plastic can. From what I hear from hard-core bass nuts, good entry level imported subs start from Sub specialists like SVS, HSU, Adireaudio etc…For music, nothing can touch subs from REL, Velodyne, Vmps. You could get something like the HSU VTF-3 for around 500$. The shipping and customs may push it higher though.
Check out the hsu and svs websites for info on these.

I totally agree... actually, i think it would be super to have one polk for every channel so taht every channel is full range...imagine that..

buurrppp

right i somewhat get the point-
also had it not been for the customs- we all would have got things from the US , singapore or dubai-

anyways till then-
regs
anirvan

av rev show is on here in delhi,am waiting for office to get over and me gettin' there-

Off the topic. but did any off you guys see Suzie belt out the bohemian rhapsody on the INXS Rockstar show on star world. Man I was blown ! It is one of my fav.I thought she was gonna screw it up………but she rocked !!!

benkenobi schrieb:

3>3k for a 120watts RMS paralleled LM4780(including PCb and transformer) benkenobi

Ben, please explain. An external class AB Pulz power amp (60W + 60W) which can be used to power a passive sub costs Rs 9000. What do I get when I get the product you mention above? How much effort does it take to use it? Does it involve a lot of soldering and electronic expertise? Can the LM4780 power normal speakers or is designed specifically for subs?

Sorry for asking you so many questions

Neutral schrieb:

Ben, please explain. An external class AB Pulz power amp (60W + 60W) which can be used to power a passive sub costs Rs 9000. What do I get when I get the product you mention above? How much effort does it take to use it? Does it involve a lot of soldering and electronic expertise? Can the LM4780 power normal speakers or is designed specifically for subs? Sorry for asking you so many questions :Y

No problems Shailesh..
Well, first you need to get the LM4780 chip..
its a bit difficult to come by in India...
For the PCb i suggest you go to audiosector.com..
if all u need is one amp)120watts)..then i think the PCB should cost u 12.5$ +6$ shipping..
then the other thing that is abit costly is the discrete diaodes for the rectifier..cost me around 450 for 8 diodes...
around 1300 for a 225 VA transformer..
and around 300 bucks for the capacitors and resistors..
soldering is no big job...practise on another PCB a bit and u'll get the hang of it..
The only thing that you may find some problem with is the soldering of the chip..cause the pins are very close together..
The amplifier can be used for full range or for sub duties..
as for the component count on the LM4780 amp..only 9 components other than the chip and the rectifier board..
that's it..!
this is what the amplifier PCB will look like when it is done..



You could use the PULZ amp too ...but u will have to bridge it..and u need to find out if it can be used ni that mode and also what is the impeadance that it can operate in bridge mode..
Cheers,
Benkenobi