[PDMagicMan]

Hi guys

I'm a new guy just getting into HC. I've decided to build my own sub as I'm pretty OK on DIY & was looking for some suggestions. I'm aiming for a sub to be used in a small room (10'x9'). I have been looking at some commercial ones and would perhaps like to build a sub that is equivalent in price to say a £900 commercial sub. So, my questions are:

1. Should I go for one larger sub or perhaps a stereo pair of smaller subs.
2. Does anyone know of any suitable hardware suppliers and components of the same quality as a £900 commercial sub.
3. Has anyone got access to any suitable plans for a suitable sub.

I've been looking at the kit on BK's site but I can't really get any idea from the forums on the relative quality & sound compared to a commercially available sub.

Thanks in advance for any help at all.

When I've done the sub I'm probably going to have lots of questions about DIY lighting, cabling and screen but one step at a time.

My kit so far, which is all still boxed as I've no cables or anywhere to set them up yet is a Denon 3803, Denon DVD-2900 and some M&K LCR55 (left/right/centre) but no surrounds yet. I'm planning on a Themescene H56 which I think is now very good value.

I'll stop now, I seem to be rambling of topic, lol.

Thanks again everyone.

[panny300]

hi pd i am about to build my first sub with loads of help off this forum,just ordered the parts from the, usa a lot cheaper but a long wait, look at the last 30 days threads sorry i don't know how to post links, but find (diy sub help,panny300) there are loads of links in there to helpful sites including where to buy and good advice from well informed people ie garyG, also look at "instruction wanted" just below your thread,hope this helps

[panny300]

hi pd i am about to build my first sub with loads of help off this forum,just ordered the parts from the, usa a lot cheaper but a long wait, look at the last 30 days threads sorry i don't know how to post links, but find (diy sub help,panny300) there are loads of links in there to helpful sites including where to buy and good advice from well informed people ie garyG, also look at "instruction wanted" just below your thread,hope this helps

[PDMagicMan]

Thanks panny, I think I have found most of that info. already as I've been looking through the forums for quite a while. The only trouble I'm having is determining the relative quality of the home made subs compared to a commercially available one if you know what I mean.

I will look again though, especially for GaryG, thanks for the reply.

I've read your posts & responses from GaryG (knowledgeable good guy seems to me) and was wondering what you finally decided to order. It sounds to me that what you are building is probably what I am after and I was hoping I might crib from your ideas/plans.

Where you from by the way, perhaps your close enough to me so we can get together maybe. I'm in West Yorkshire.

Cheer mate.

[panny300]

going for garys suggestion in the (instruction required thread)" i will have to find out how to post links", volume of 8.1cuft 15"dvc driver 250w plate amp without the bass boost and 2 ports which i ordered last night from parts express in the usa. CPC do the same amp for 89 quid plus the vat but could'nt find anywhere that sells decent 15" drivers cheap enough in the uk, www. iplacoustics.co.uk sell a sub kit for around £300 which they claim is as good as a £800 commercial one,click on audax reference units on the site and scroll down to sw3 sub,a couple of people bought one on this forum but i don't think they have reported back on how good they were, sean at parts express technical has been brilliant with advice. i have plenty of time to decide on dimensions and finish of the box

[GaryG]

The only trouble I'm having is determining the relative quality of the home made subs compared to a commercially available one

Build quality or sound quality?


Obviously the build quality is dependent on your DIY skills or the skills of the cabinet maker you employ.

Sound quality is dependent on the type of sub you decide to go for, the quality of the components and how well braced your cabinet is.

I have been looking at some commercial ones and would perhaps like to build a sub that is equivalent in price to say a £900 commercial sub.

I presume you mean the performance of a £900 commercial sub rather than spending £900 on components?

Given the size of your room a 12" driver will be sufficient with around 200-250w. Around 5.3ft^3 for one of the Dayton DVC 12" jobs with a port tune of around 21hz. The Adire Shiva comes in at around 7ft^3 with a port tune of around 21.7hz

Slightly better quality drivers would be the Dayton Titanic 12 MKIII or the Adire DPL12, again around the 7ft^3 cabinet. At that volume I'd be inclined to go for a 15" driver, slightly bigger cabinet but more output, and for me I prefer the sound of a 15" driver over a 12".

Partner that with a top quality plate amp like the Hypex HS200 and you're ready to take on the best as long as you keep the output within the linear part of the drivers BL curve, as you drive the sub harder you go out of the linear area and the distortion increases. To avoid that you need a driver with a flatter BL curve or more drivers.

Here's some more info:
http://www.adireaudio.com/tech_papers/xbl2_motors.htm

[PDMagicMan]

Thanks Gary, that is most helpful. I have a lot of reading to do.

[PDMagicMan]

Gary

Sorry to be a pest, I bet you get this all the time but I have a few questions if thats ok?

I'm not into loud bass, I won't be pushing it/them hard but I do like to know the bass is there when I'm watching a film if you know what I mean.

So my questions are:

1. I do have room for two subs so do you think I would perhaps be better with two 12" subs or one 15" sub? Do two subs allow you to go lower in frequency than one?

2. I assume I will need to use some software to design the enclosure sizes so can you recommend any software packages (that are free)?

3. I can handle a saw so complexity of design does not really worry me, with that in mind, what design of sub do you think would be best? (Sealed, ported, passive)

4. Who would you say are the best suppliers for components?

5. How do you 'tune' a sub? Will I need any sort of measuring equipment? I've read about SPL meters & I assume SPL means 'Sound Pressure Level', just a guess.

6. Do you know any good sources of ready made designs for any particular drivers?

Thanks for your help, I do appreciate it.

Regards

Paul

[GaryG]

Hi Paul

1. I do have room for two subs so do you think I would perhaps be better with two 12" subs or one 15" sub? Do two subs allow you to go lower in frequency than one?

The frequency extension is dictated by the driver and the enclosure type and size, not the number of enclosures. If you have the space for two enclosures then all things being equal, a single enclosure of twice the size will give a lower frequency response. Multiple enclosures have the 'potential' for a more 'even' response but require more effort in positioning and equalisation. The difference between a 12" driver and a 15" driver is that the 15" driver will need a bigger cabinet to achieve that same response as a 12" driver, however a 15" driver will give more output for the same input power as a 12". For example, comparing Adire Audio's 12" Shiva and 15" Tempest http://www.adireaudio.com/diy_audio/...dire/shiva.htm http://www.adireaudio.com/diy_audio/...re/tempest.htm
The enclosure size of a ported Shiva is around 4.6ft^3 with a port tune of around 21hz, the Tempest needs an enclosure size of around 9ft^3 with a port tune of around 23hz, however the Tempest enclosure will be give around 1.5db more output from 25hz upwards.

2. I assume I will need to use some software to design the enclosure sizes so can you recommend any software packages (that are free)?

http://www.linearteam.dk/default.aspx?pageid=winisdpro
http://www.danbbs.dk/~ko/ubmodel.htm
http://www.adireaudio.com/Files/Adire.zip

3. I can handle a saw so complexity of design does not really worry me, with that in mind, what design of sub do you think would be best? (Sealed, ported, passive)

Have a read here:
http://www.diysubwoofers.org/
At the frequencies we want to use a sub for it's response is dropping off very quickly. The most popular methods to combat the falling frequency response are a port, a passive radiator or electonically boost the low frequency response. Each have their own pros and cons. My current preference is for a sealed enclosure with electronic equalisation using a Linkwitz Transform to combat the falling response and a BFD to equalise the room induced peaks and troughs. The reason I chose the electronic method is that finding the best location in a room for a sub can be difficult and integrating it with the main speakers can also be troublesome. With a servo sub or a ported sub the frequecy response is fixed (unless you have tuneable ports) which can lead to boomy bass, with electronic equalisation it's much easier to integrate the sub into the room.

http://www.marchandelec.com/wm8.htm
http://www.trueaudio.com/st_lkxfm.htm
http://www.snapbug.ws/bfd.htm

4. Who would you say are the best suppliers for components?

Most of the suppliers are in the USA. Parts Express, Adire Audio and Stryke Audio are the most well known. In terms of service and speed of delivery I would go with Parts Express.

5. How do you 'tune' a sub? Will I need any sort of measuring equipment? I've read about SPL meters & I assume SPL means 'Sound Pressure Level', just a guess.

The analogue radio shack SPL meter is popular. To tune the port you would need to use a PC to generate the tones or some test tones burnt onto a CD.

Thanks for your help, I do appreciate it.

My pleasure!

[panny300]

hi paul, i found this site useful for punching in numbers and trying different parameters www.loudspeakers101.com it has calculators for various specs, if you order off parts express just check method of payment,i paid with visa credit card,they emailed back saying could'nt verify my card as it was a british bank,so i forwarded payment by paypal but my card was refused,checked with card company parts express HAD verified my card and luckily card company stopped paypal(I HOPE) because of unusual use, I AM SURE IT WAS A GENUINE MISTAKE BY PARTS EXPRESS,just warning so you don't do the same.

[PDMagicMan]

Thanks for that Panny, let me know when you get your parts thru, I'd be interested in how your build goes.

I've been looking at the costs etc. & looking at the SVS subs that Ian J raves about, I'm not sure that building my own would be much cheaper than buying an SVS 25-31 PC+ which looks like an excellent price.

I know Ian J raves about them as I said but I would love to hear GaryG's opinion if he has had a chance to listen to one.

How about it Gary?

Cheers

Paul

[panny300]

how much is the svs ,is it from the states, i wonder how good the tannoy rsub15 is which is on sale at richer sounds and petertyson.co.uk for 288 quid was supposedly 700 quid

[GaryG]

Hi Paul

Ian was kind enough to give me a demo of his SVS, however I would prefer not to comment, there are many happy SVS owners on this forum but there's been more than one person who has bought as SVS and not been totally happy with the purchase.

One of the benefits of building your own sub is that you can buy a driver with known T/S parameters and can therefore change your design if you are not fully satisfied with the final sound. For example, when I built my first sub I wasn't completely happy with the plate amp. I subsequently went through 4 more before I found what I looking for. I also ended up going for a 15" driver instead of a 12" as I prefered the sound.

In case you think building your own is difficult I think I should point out that I'm a very demanding listener so most people would be more than happy with the first sub that I built. However I couldn't quite get the sound I was looking for until recently. I now use a pair of Adire Tumults in a 16ft^3 sealed cabinet giving a Q of around 0.5 with a Linkwitz Transform to give me a flat response into the 'teens', a seperate low-pass crossover, a BFD for room equalisation and a couple of audiophile monoblocs. The flexibility of building my own means I've finally got a sub that meets my demanding requirements.

[PDMagicMan]

Fair comment Gary.

Panny, the SVS sub I'm looking at will work out at around £650 all in with carriage & VAT. Of course I'm not sure what to do now, lol.

I think I will leave a decision until after the weekend, I'm off to the show near Manchester Airport on Sunday to have a drool over lots of lovely HT kit.

[panny300]

hi paul it 's should cost me around two hundred and forty pounds including carriage, vat and import duty for amp + driver, then around thirty quid for the mdf,and if garys right should have a really good sub for 280 quid,if gary reds this, how do i put a couple of photos of my ht room into a thread, i did the test of putting the sub i have now in the listening position and took readings around the room, it was low in the position my sub is usually, so needs moving but where,i am thinking of (h) 24"
(w)24 (d)26" get it all out of a 8x4 sheet, it's big so where to put it

[GaryG]

Paul

If it's of any interest I have the bits for an unfinished SVS clone lying around that I would be prepared to sell. The driver is the legendary Adire Shiva, the tube is 39"x16" and the plate amp is the Hypex HS200 which I consider to be one of the best plate amps that money can buy. Taz, the forums resident woodwork expert was going to do the end-caps and stand for me for about £50 but I've just not got the time to finish it off at the moment. If you want any more information or a price send me a PM.

[PDMagicMan]

Check PM Gary, I would like details please.