First DIY Sub, need suggestions. (1 Viewer)

[Peter Jessee]

Unsatisfied with the extension, or the output? Flat to 25 Hz and -4 dB at 20 Hz is great extension. If you're used to +6 or +10 dB at 30-40 Hz as 'normal', a vented system will be your cup of tea. In this era of 130 dB car woofers and THX certified theaters that are -10 dB at 20 Hz but +10 dB at 40 Hz, few people have heard accurate bass.

I don't want to jump to conclusions about your tastes or experiences, but have you measured the in-room response of your sub? Designing for flat anechoic response will give you a grossly boosted in-room response below 40 hz.

Peter

 

[Dustin B]

Your room is 10'x10'x10'. A cube is the worst room shape possible. Have you ever tested the response of your DLS 10" in room.

No matter what, with that room, I think you should count on investing in a Radio Shack SPL meter and a Behringer Feedback Destroyer. Don't think you'll get any sub to sound good in your room without these two items.

 

[Kevin Patterson]

If your worried about size have you thought about building the box up(vertically)? It will have a smaller footprint but still give you the sixe you need.

 

[Ryan Schnacke]

That sealed sub was only around for a short while until I decided to put the DVC in a vented sonotube. Didn't bother to measure it. I have measured the SVS that's in my living room and its fairly flat. No big boost in the bottom end and this doesn't surprise me since I've got well over 6000 cu ft of open space considering my very open floorplan.

So I don't think I'm particularly spoiled by a bottom-heavy HT sub. And I've never had a car stereo that was anything more than the factory standard. I just wasn't happy with the sealed DVC. It's a very nice, sturdy box and I have since put a different woofer in it and given it to my brother-in-law. Sounds a little better/deeper with the other woofer - a Bazooka car audio woofer of all things! I can't explain it, I'm just telling you what I heard.

 

[Geoff L]

Is the closet enclosed on all sides, meaning back, sides, and top?

Is it open or have a door on the front, and if so, having a door, what type?
Reg hinged, folding of some type, slatted with vents type thing, etc?

I ask, cause you could possibly make a ported or sealed sub using part of or all of the closet itsef. Maybe even an IB type sub..

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Depending on it's height, width, depth, maybe only half of it or less would be needed depending on it's size, driver, used, and the box alignment choosen.
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Just another idea ~{that might work and actualy "may" require less work}~ than building a complete box "for what ever you where to choose to go with".
This when compared to when building a complete traditional sub box, sealed or ported.

Others have built IB's, also Sealed and Ported subs using part of or all of a closet or room alcove type area.

Just throwing it out their....Catch

 

[Paul Spencer]

A couple of points:

1. The Shiva is a great driver, but also its worth considering some alternatives - Dayton DVC (cheaper, similar but is ok with a smaller box), Stryke SAE 1204 (cheaper, similar but has spring loaded terminals and a cast basket - better quality), Peerless XLS (great for a small sealed box, better build quality than all of the above).

2. In a small room a small sealed box is probably going to sound the best. Room gain can make vented subs boomy in small rooms.

3. Perhaps you can put the sub under your bed.

4. Vented subs needs to be bigger to fit in a decent sized vent that would chuff when you crank it. Typically 60 - 100L. Sealed you can get away with 28 - 50L and use eq to get deeper bass if you want. Sealed tend to sound tighter and more musical.

5. For deep HT effects you might go with a vented sub but in a bedroom a sealed sub will sound better and should have plenty of output. What you gain in output with vented you will be lucky to use when anyone else is in the house!

6. Crazy idea - sell your bed (except the matress), get a driver like the Dayton 15" infinite baffle driver and build a subwoofer base - a simple box out of 1" thick MDF well braced with no vents. If it's big enough it will effectively be infinite baffle which will sound better than a small sealed box or a vented box.

7. Whatever you do try to keep the typical listening distance of the main speakers and the sub about the samee.

 

[Andrew-_-_P]

"6. Crazy idea - sell your bed (except the matress), get a driver like the Dayton 15" infinite baffle driver and build a subwoofer base - a simple box out of 1" thick MDF well braced with no vents. If it's big enough it will effectively be infinite baffle which will sound better than a small sealed box or a vented box."

Would that work? As I am also building a sub for my room and dont have much open floor space..hmm. And i figure it will cost the same as my other sub plan.

 

[Paul Spencer]

Andrew,

Will it work? Depends on what you want to achieve! The main performance advantage is that it is a very very low Q sealed alignment, to the point that it can probably be considered infinite baffle. Transient response begins to approach that of a dipole which is the best transient response you can get with a dynamic driver - a normal sealed box acts as a spring which impairs transient response, and a vent compresses dynamic peaks which gives bass its full impact. You give up the output of the vent but in a bedroom you don't really need it.

Keep in mind, it's a lot of MDF and you will either need 4 people to lift it if build solid enough, or assemble it in your room!

Just make sure the driver is protected so you don't kick it when you get out of bed! This is something you may do if you make a bass alarm clock to shake you out of bed!

 

[Cam McFarland]

Another possible benefit....


Your girlfriend/wife might like it more than you do...

 

[Andrew-_-_P]

Well i measured the area underneath my bed and don't think it is large enough, in height. Its 82x58x8. Definitly not tall enough...unless i raise my bed about 7-8 inches. So I'm scrapping this idea.:frowning:

 

[Paul Spencer]

Is this all that's stopping you? You don't need to raise the bed that much. Make the sub downfiring with the part in which it fires down inset 2". Now you need to make your bed just slightly higher, depending on the driver. There's a few different ways to do it if you think creatively - don't be too quick to ditch an idea because of such an obstacle, unless you find it doesn't do what you want overall.

 

[Paul Spencer]

lol @ Cam ....

Well here's a design that might do it better. Fire the sub upwards to the matress with a flush mounted grille and a large ported EBS! Try a few Tumult's and it will also double as a massage bed with a signal generator attached!

ok, I'd better stop now ...

 

[Geoff L]

I think first off, what is the problem with the DLS?

Not enough output/spl, not enough extension, sounds to boomy, just what is the complaint/s with your current sub.

Also have you measured/plotted the response of the sub in your room at your listening postion?

The Tiny Mighty as it's been called, should provide enough output in a 10 x 10 room to make most happy, not all tho.. You could (and most likely have some huge peek and dips in your response) causing the sub to sound less than ideal....

Have you tried to experiment with different sub locations just to see what it sounds like, or better yet, measures like??

There is no question a better/bigger sealed, ported, or what ever sub may provide more spl and possibly better extension, (at least when modeled up). BUT if it's placed in the same spot as your current sub the very things I suspect that hurts/bothers your DLS, will be the same or could even be worse with a new better DIY sub.

An Spl meter and Freq disc along with a little time spent measuring just what the DLS sub is doing FR wise,,,, (would be well worth the effort).
This "before deciding" to build anything period.....!
I'll bet you'll find your subs response is all over the place with some huge peeks and nulls causing it to sound, well yucky.

=======================================
Regards
Geoff

 

[Morlan Liu]

Hi Geoff,

I have a SPL meter and Video Essentials. I just calibrated it to about 80db using the pink noise. I don't really understand the other tests you refer to so if you can explain it I'll be happy to perform them.

Thanks!

Sincerely,


Morlan Liu

 

[Cam McFarland]

Hey Morlan,

I think he is saying to run frequenct tests using sine waves that can be found here .

Burn them to a CD and run the toneschecking the SPL from 10Hz to 160Hz to get a better picture of what's going on.


I run it through my DVD player which plays MP3s & it shows what freq. is playing to make it easier to keep track while writing it down.

Hope this helps......we have all been through it....

 

[Geoff L]

Yes, plot the sub freq response and it's spl (to find) the spot/s where there maybe large peeks and nulls.

Take any tone/sine say 30-Hz and turn the receiver up till you read say 80 to 85db when the spl meter is set to C-weighting and slow scale. Now don't change the volume on the receiver and just continue up and down checking the spl with each freq. You don't need to do ever single feq, 10-11-12-13-14-Hz etc up, about every 5Hz to 10Hz or so will give a good idea of whats happening. Find a bad spot (peek/null) and close in then with closer together freq/Hz measurments. You may have to go up or down withth spl meter scale, (ie) instead of the 80db scale on the meter you started with, you may have to go up or down to get a proper spl reading on the freq being played.

You'll need to (add the correction factor numbers to the spl meter) for those (spl numbers you record at the specific freq taken/used)..
I don't have them here at the moment, but someone will surely give them to you with a link, or a quick search should find them.

This will allow you to find where their may be possibly large swings in spl (up or down) across the sub response into the bled area of your other speaks..
This mostly will be created by your rooms interaction with the sub and it's placement.
Move the sub (as little as a few feet) and re-measure and you'll find that things change across the subs FR, could be for the good or bad. Your ear will tell you usualy if it's a better spot, but the spl and freq disc don't lie.

Once this is done you'll find what your sub is really doing in room...!

A 99.00 new BFD might be all that is needed, pari Eq. (A used one is for sale right now is the FS area/much cheaper) to really make a big difference,,,, or a new/different placement of the sub....
Or possibly both or all three.
Meaning a needed Pari eq, the wanted new sub, and new placement for that new sub.

A new sub could still be built, but you need this basc info to see what is happening in your room currently with the sub and it's placment you already are using....

This in order to make some better informend decisions on what to do...

Cheers
Geoff

 

[Morlan Liu]

I heard that even though the receiver sends frequencies under the crossover point to the sub, some of it still goes through the mains?

How do I isolate the sub and make sure the sound is just from the sub?

I have downloaded the sine waves and will try this today.

Thanks!

 

[Geoff L]

Leave everything in the receiver set up as usual, crossover points, sub volume, redirectied bass, etc, just disconnect the speakers...
Center, Mains, Surrounds, Rear Center/s if you run one/them.

Just one wire removed from each speaker will do the trick.
Do this if you CAN'T shut them off in the receiver.

This is just to check the sub itself, after you check that, then add the speakers into the mix and take another set of measurements with the speaks running along with the sub.

Receivers VOLUME control (not touched from your first sub measuring). You'll find that where the crossovers meet (speaks to sub) that the upper freqs say 100 or so down to around ?Hz will change possibly in spl.
This will depend on where you have crossed your speakers over to the sub.

Don't forget to add correction factors to the spl you measure for each Hz in both sub alone, and when you measure the sub with speaks all running.

Take measurements from the same postion both times.
You may find it easier to take the meters spl reading and writing that down for the freq being read. Take all the measurements (and then add the corrrection to those numbers) after words.

I think in your very small room your going to find your bass FR/Spl is all over the place in at least a couple spots. This can cause even the best sub to sound terrible, but with some work possibly on phase, sub placement, crossover selection, and maybe a pari-eq if real bad, that even the DLS can sound LOTS better!

Won't know till you test the sub, then speaks & sub, and get some numbers up for us to see.

 

[Morlan Liu]

I just did the test with the receiver set to STEREO.

FreqAverage SPL
3080
3584
4075
4575
5078
5584
6085
6575
7085
7584
8085
8587
9087

 

[Geoff L]

Try moving the sub as you certainly have a swing in spl of nearly 10db in the punch bass area 50 to 40Hz. Below 30 I have no idea whats going on.
The mid to upper 30's and below is where the HT shake area starts to come alive.

I have (no idea if your numbers are corrected) and it seems I can't get you to answer a few questions that I asked when you PM'ed me. Are your numbers corrected being one of them, and also would/could you add 25 and 20Hz to the table.
I'm sure you have output/useable output, to at least 25Hz in that small room with all the free gain you should be getting with the pictured sub placment.

The (BFD) is a parimetric Eq that many use here to flatten their sub response & or boost certain type sub designs.

It will allow you to dial in a specifc freq or freqs and pull them down or boost them. Also, most imortant it allows adjustment of the (Q) of them, or width of how far out you want to go away from the dialed freq your trying to pull down or boost.
This is what is different about a pari-eq compared to a standard eq with fixed freq and Q width.

Always/nearly always better to pull stuff down to flatten FR, as boosting a freq null/hole/room freq suck-out as it will just eat the subs headroom nearly always.

You might do some searchs here on flattening sub response, parametric eq, using a BFD, sub placement, etc.

If possible move your sub anywhere and re-measure, even if only to see how the room will effect the subs response.
Even if it's just turning it/facing it in a different direction right where it is.

This is basic sub placement and FR response without even getting into phase issues, crossover interaction, and other stuff that can affect the subs FR/Spl at the listening postion.

Best of luck
Geoff