DIY "Accurate" sub under 10k? Is it possible?

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AVcrazy

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Okay so before you tell me it's not, please let me explain my situation.

We have recently moved into our new place and things have started to settle down. My current listening room is about 13ft*11ft*11ft. Initially I had lot of problems with echo and acoustics but after struggling for about 5 months and a LOT of fiddling around, I've got the room sounding almost decent. My setup includes a pair of Yamaha NS10M driven by a yamaha as500, fed by a PC through a Beresford Caiman DAC.
In the current configuration I'm about 8-9ft from the midline of the driver position and getting good imagery. The speakers are indeed quite revealing and I'm happy coz I'm a detail freak and that is exactly what I was looking for in the first place.

What I have noticed is that since my place is quite distant from rhe hustle bustle of the city, the average volume levels at which I'm listening have gone down drastically. The volume pot on my As500 is never over the 9 o'clock position. And even at this point the music is quite loud for my room.

Now, although the rest of the things are perfect, I'm secretly yearning for some bass. Not the chest thumping or thunderclap bass of the new age geode-shaker subs; but just the slight thump or the low frequency extension required to complete my otherwise satisfactory setup.

Since I'm enjoying my setup much, replacing the speakers is out of the question. So I'm looking for a sub under the 10k category. Now I know that this is quite wishful and I might not be able to do it, but is it possible to build one?

How about a 8 inch driver in a sealed enclosure? I have an old amp lying around (75wpc, nice clean amp with a warm sound) would it be able to run this single woofer driver and give me the accurate low frequency extension I'm looking for? My room is small and my required volume levels will be very low.

My plan is to feed my old amp off the LFE out on my as500 (using a mono splitter RCA cable) and then wire this sub with any one of the terminals on the amp. Would this work? Better yet I'll get 2 such subs in the future and make a sterero sub pair!!

The thing is that I'm very happy with the detail in my system right now and don't want to muddy the waters with a diy experiment. More importantly I've got little moolah to spare at the moment. Should I wait and buy a monitor sub like a yamaha hs5-sub or should I pursue this experiment. What else can i do to make my system go deeper?

Any valuable suggestions will be deeply appreciated.

Thanks and Regards!
:)

PS: I have a friend who offered me his car sub for free and since he was otherwise throwing it away, i got it home and tried to get more info on it. Its a sealed sub with a sony xplod 12inch driver that has "1000watts" inscribed on the diaphragm. I wasn't able to get much info on the model number but comparing the online pics and this woofer I'm suspecting that it is a Sony Xplod XS-L120P5H. Can i run this sub on my measly amp? If yes, would it do fine as a makeshift sub until i get/build a proper one?
 
AVcrazy said:
I have a friend who offered me his car sub for free and since he was otherwise throwing it away, i got it home and tried to get more info on it. Its a sealed sub with a sony xplod 12inch driver that has "1000watts" inscribed on the diaphragm. I wasn't able to get much info on the model number but comparing the online pics and this woofer I'm suspecting that it is a Sony Xplod XS-L120P5H. Can i run this sub on my measly amp? If yes, would it do fine as a makeshift sub until i get/build a proper one?
Click to expand...

You sure can try this DIY. However, what you need to check is the Ohm and power rating of the driver. Drivers made for the car are made differently than those meant for indoors.

Your friend must also be having an amp which he must be using to power this sub. If its available, pick it up too. Then all you need is a AC to DC converter to power the amp. That amp should be able to drive this Sub, the way its meant to be driven. A home amp is ideally not suited to car subs.

All the best.
MaSh
 
75 WPC should be enough if you need just low frequency reinforcement, and not proper subwoofer bass. Surprised that somebody put a low end sub in a sealed box - they usually end up in ported ones

If you want accuracy, you could add an active equalization network in between
 
Decadent_Spectre said:
If it has the excursion and the required T/S for the box size to utilize excursion without thermal failure I don't see why "low end sub" can't be used in a sealed box.
Click to expand...

I'm not saying it can't be used - it's just the way he found it - people who buy budget subwoofers, are usually looking for maximum bass or boom, and they often end up in ported boxes, where they, along with an entry level amp, can cook up some decent bass
also at the OP, you sure your amp can't be bridged? Which one is it ?
 
I can't speak to the OP's tastes but generally speaking when people seek a sub for music they need energy in the 40-80Hz band and for movies in the 25-60Hz band.

Looking at what a quick google produced and his description I reckon he is lacking that 40-80Hz energy a bit.

Boom and so forth, very subjective, personally I don't subscribe to a flat response but yes for maximum output on a budget a ported or bandpass enclosure is often preferred although seemingly the OP isn't looking for that.
 
@Mash: Hmmm. Im really not inclined to use the car sub actually. This will be a makeshift sub for the time being until I get around building/buying a decent one. So spending in a ac-dc converter etc is not an option.

@greenhorn: YES! "Reinforcement" is the right word. Im not unhappy with my current setup. It just lacks that low-end presence. And what is a active equalization network? Is it like a compensation circuit? Do i need that? Coz im planning to supply my amp from the LFE out on my yamaha amp (outputs a signal below the 200Hz). The amp I'll be using is an old Sony MOSFET amp. Very decent for its size and age. I dont exactly remember the model number. Its not bridgeable though. Will i blow my amp if i play this car sub at lower or moderate levels?

@ds: Yes I'm not exactly looking for the "boom". I think the right word here would be "viscerality"; my music is lacking that viscerality in the low end of the audio spectrum. The driver that you've recommended is a car sub driver. I'm looking for a home use sub driver (lesser power requirement and greater impedance so that I can power it with a any small amp).

See I'm not inclined to use the car sub. Im doubtful of its performance. I want to build a smaller sub that can reinforce my systems low end and give me that "fuller" sound. More importantly since I'm crazy about detail, i want a sub that is most accurate and does not eat away the lusciousness of my current configuration Is it possible to build one under 10k?
 
AVcrazy said:
@Mash: Hmmm. Im really not inclined to use the car sub actually. This will be a makeshift sub for the time being until I get around building/buying a decent one. So spending in a ac-dc converter etc is not an option.
Click to expand...

Ahh okay. In that case, just check the impedance on the amp, you dont want to blow it, since car speakers are designed with very low imedance, 4ohms usually and thats a lot of current going back to the amp. Make sure your amp supports 4ohms or lesser.

AC to DC converters are not that expensive, survey the local electronics market.

AVcrazy said:
See I'm not inclined to use the car sub. Im doubtful of its performance. I want to build a smaller sub that can reinforce my systems low end and give me that "fuller" sound. More importantly since I'm crazy about detail, i want a sub that is most accurate and does not eat away the lusciousness of my current configuration Is it possible to build one under 10k?
Click to expand...

being doubtful is good and if possible try testing it out in a room before commissioning it for duty. Car speakers are designed for small areas. Now you would have to take a call of how the Sub performs when you place it in a much bigger area such as your room/hall.

MaSh
 
You state visceral but that requires output and that means power and sufficient displacement in a sealed cabinet depending upon the frequency range of interest.

The car audio driver is a fine choice from the perspective of science, yes it does have certain traits that are commonly found in car audio drivers but its not a bad driver. It has dual 4 ohm coils so it can be an 8 ohm nominal load which should be fine for your amp. Whether it produces enough output is a matter of personal taste with the intended amount of power. If you are seeking to get the most output from minimal amounts of power and a visceral feel then you should consider a front loaded horn though it will not be small and probably not in your budget.

I recommend the driver as a general purpose sub to do what you asked for and because it should be relatively inexpensive allowing you to meet your budget.

"Home audio" drivers are often over priced and under performing compared to car audio or professional audio.
 
AVcrazy said:
And what is a active equalization network? Is it like a compensation circuit? Do i need that? Coz im planning to supply my amp from the LFE out on my yamaha amp (outputs a signal below the 200Hz). The amp I'll be using is an old Sony MOSFET amp. Very decent for its size and age. I dont exactly remember the model number. Its not bridgeable though. Will i blow my amp if i play this car sub at lower or moderate levels?
Click to expand...

1. yes
Subwoofer equalization

2. the amp should survive, if it is rated at 4 ohms
 
Decadent_Spectre said:
If it has the excursion and the required T/S for the box size to utilize excursion without thermal failure I don't see why "low end sub" can't be used in a sealed box.

Infinity 1262w Reference Series 12" subwoofer with dual 4-ohm voice coils at Crutchfield.com

OP, ^ this driver may suit your needs depending upon local pricing.

Good Luck!
Click to expand...

Spot on Driver. Its actually a car sub, but does beautiful in home use. Very accurate too.

Cost some where from 6K to 7K and 3K for the custom Box and a nice sub is there.
 
@ds: Hmmm. I was given to understand that home use drivers were more accurate and had way less distortion. Also the driver that you've recommended provides a load of 2ohm instead of 8. At that load won't the distortion be too high?

Okay what about this: I already have a car sub. What if I get a bridgeable amp (AC) and run it through this? Will it work? Also please can someone help me understand what an active equalisation network is and how to set it up.
Thanks for the help guys! Bless ya!
 
the active eq network is a circuit you will need to design and build yourself. Design guides are available online, which you will need to understand and implement. same goes for the soldering and parts.

If you want cheap, its not going to be easy
 
AVcrazy said:
@ds: Hmmm. I was given to understand that home use drivers were more accurate and had way less distortion. Also the driver that you've recommended provides a load of 2ohm instead of 8. At that load won't the distortion be too high?
Click to expand...


Those who had given you those ideas are those who had not understood the details fully.

Its a DVC Sub. fyi So this will suit normal Amps.

"Dual 4-ohm Voice Coils: This woofer features dual 4-ohm voice coils that offer flexibility in wiring. When the voice coils are wired in parallel with each other, the woofer presents a 2-ohm mono load. When the voice coils are wired in series with each other, the woofer presents an 8-ohm mono load. In addition, each coil may be connected to a different amplifier channel and each channel will see a 4-ohm load."
Click to expand...

AVcrazy said:
Okay what about this: I already have a car sub. What if I get a bridgeable amp (AC) and run it through this? Will it work? Also please can someone help me understand what an active equalisation network is and how to set it up.
Thanks for the help guys! Bless ya!
Click to expand...

Yes it will work. But you were asking for an Accurate Sub and not just a Sub:p
That Xplod sub is far from accurate. I just hate those.

Btw, I am not even going to venture in to active Equalisation first for technicality and complexity and second for reason because in a sub building, this probably comes last.
 
As noted the sub can be wired for 8 ohms.

As to accuracy and distortion, distortion most of the time is something that people do not object to, it is only when you start reaching thermal or mechanical limits that it can become an audible problem for the average user.

Poeple inherently like certain flavors in everything in life and sound is no different. Personally a flat response is not something I enjoy though it is more accurate.

There is a lot of complexity involved in making an accurate sub and it can not be achieved by overlooking the other factors such as the room which is a very significant contributor and I'd recommend a DSP but that will not fit within your budget. You could give the MiniDSP a try.

A driver is a driver, what makes a car or home audio driver often tends to be about the frequency range it is designed to excel in and in what type and size of enclosure. Normally if you take a car/pro driver and make some minor cosmetic modifications and market it to home audio its price automatically shoots up as the home market associates price with quality which is not really accurate.

The popular Seaton Submersive uses very simplistic drivers that are not very expensive or special, but the price charged for it along with the designers goodwill and reputation is what makes these desirable for most. Inherently it is a simple design and what people are paying for is a plug and play solution where the designer has made reasonable choices of driver vs box size,power,limiter and processing for the intended bandwidth.

Try to think less in terms of home and car and more in terms of a drivers individual merits vs price vs intended usage.

Just IMO, YMMV.
 
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