Using DBX Subharmonic Synthesizer for better Bass Response ?

[MyPillowTalks]

Hello everyone!

I hope this is the right place for me to ask this question.

Recently i came across this DBX 120A Subharmonic Synthesizer. DBX says: "The wildy popular beat of "House Music" is likely to be driven by the throbbing, low-end bass of dbx® Subharmonic Synthesizers in clubs around the world. "

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From my rough understanding, this machine mixes/add harmonics(F[SUB]h (harmonics)[/SUB]) to the already present fundamental sound frequencies(F[SUB]s(source)[/SUB]) present in the source.

I understand that by mixing two frequencies, in this case the added harmonics F[SUB]h[/SUB] , and the original fundamental frequencies F[SUB]s[/SUB], will result in the production of frequencies stated below, on top of the already present original frequencies.

1. F[SUB]s[/SUB] + F[SUB]h[/SUB]= F[SUB]H[/SUB] (The higher frequencies)
2.F[SUB]s[/SUB] - F[SUB]h[/SUB] = F[SUB]L[/SUB] (The lower frequencies)

Therefore the machine filters out F[SUB]s[/SUB] + F[SUB]h[/SUB], leaving me with original F[SUB]s[/SUB] and the produced F[SUB]L[/SUB] .
But the F[SUB]L [/SUB] produced is the lower octave of the original frequency F[SUB]s[/SUB](Like playing the middle C on a piano with C from an octave lower).

Therefore achieving a subharmonic frequency. Is this roughly how this machine works?

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Ok, actually what have been troubling me is the following:

I intend to use this synthesizer with one of my subs(PA subwoofer) which have frequency response of 40hz - 200hz.I crossed it at about 80 hz.

If i use the subharmonic synthesizer with this subwoofer, will there be a difference in the bass produced?

Like if i buy this synthesizer, can my system really produce the lower end bass?

I want to add in the really low frequencies that some PA subwoofer seems to have trouble producing, im sure you all know the bass from some PA subwoofer can be loud and chest pounding but it's not low enough...unless those danley sound lab or tapped horns...

i have read somewhere it is still limited to the driver's response, it will burn the voice coil etc.

The following video is a movie trailer. Part one of the video is encoded without a subharmonic synthesizer, but part two of the video is encoded with a subharmonic synthesizer. Part 2 sounds better.

http://vimeo.com/1604473

Thanks you a lot for you advices in advance.
Sorry if the question seems confusing, it's the best way i can phrase to bring the point across.

 

[kongwee]

Never use any subharmonic.
If the source(normally bass and kick drum) have very low frequency, normally I will do a 30hz and above high pass cut-off to make the woofer move like piston.
Then add compression if necessary.

 

[MyPillowTalks]

Hey thanks for the advice!...is it because subharmonics will cause harm to a PA subwoofer?

Actually i don't intend to use the synthesizer with kick drums or live band.

I am intending to use it to enhance music from CDs/MP3s/DJ mixing(i still try to ensure input signal hovers around 0db), for example background music during birthday parties, i want the low end to be more distinct without buying better subwoofers.

Using this equipment for playing MP3s will be safer for the speakers than using it for kick drums or live sound right?

Another reason im looking at this equipment is because i miss the bass from another subwoofer of mine.

It's 'custom built' active 18" PA sub (now dead; short circuited main transformer i guess) which delivers warm farts of bass, it's those low end bass that fills up the room.
The bass is not very loud nor chest pounding, it feels like the sub moves a lot of air gently forming this air pressure-like bass that fills up the room and rumbles things.

So im wondering if this synthesizer can help reproduce that kind of bass or not

Sorry for the questions...i am very new to sound reinforcement and not trained in this area.....

 

[kongwee]

The woofer transducer itself, it is not easy to be harm when they get bigger in size.
It is the electrical and electronic part that is easy to spoil.
The heat and the vibration is the killer.
Those commercial active sub will have protection circuit to prevent them from harm.
If you see CE(Europe side, US dunno the label) label, that mean the product meant the operation safety under it given spec.

18" woofer, it is very hard to break.
Most likely, it is the under power electronic.
I used to service a lot of sub, their damage is on the power supply or the amplification part.
Nothing due to source, if there is no high DC leakage.

 

[MyPillowTalks]

Hmm..i think i learnt sth new! I also notice PA transducers tend to have 'dual layer' or more surrounds.

Can you share a little with me how do you check if a transformer is spoilt? Is it by measuring ohms at pri and sec?

I suspected that my transformer has died, as it has blown a main fuse a few times and now it has no power.
The circuit also didn't state what voltage value it needs.

At first i thought the bridge rectifier has short circuited but after de soldering and checking they are fine....

 

[kongwee]

Transformer is alway a close circuit whether on the primary and secondary winding.
Of cos, there should be some ohm reading, normally lower than 1ohm.
There should be a detail spec on the transformer itself.
You should replace the main fuse with a bigger fuse.
However, do you check your main fuse to be slow blow or fast blow.
Make sure the fuse is slow blow with the same rating.
Big transformer has initial peak current up to six time the operating current when switching on.
This huge in-rush current is not solely on the transformer itself, also the electronic in the power supply.
Then change to higher rating with slow brow.
High power device will normally feature a "warm-up" circuit in the power supply.

 

[MyPillowTalks]

Hello, thanks for your reply.

I have checked my transformer today, and very 'happy' to see that there are no ratings....there are no papers stating the output voltages....guess they must have purposely removed them.

I suspect that the secondary winding of the transformer(toroidal) has short circuited or melted causing open circuited?
i ran a simple continuity test on a few of the outputs leads.

There are two groups of output wires tapped out from the secondary winding, i ran continuity test between the first "group" of the wires and the there is continuity. However another set has no continuity. But there are some ohm readings....so is there a problem or not?

After thinking back, since it's all winding there should be continuity, but then again why doesn't the another set of wires have continuity.

I think i shall bring it to school and ask my friends about it.

Thanks for all of your advice! Really appreciate it

 

[kongwee]

Since there are two set of output, very likely there are two set of secondary output.
There are two set point, you will not have continuity.
Since no rating, the last you could do is to find the brand and part number to search for the spec.

Hello, thanks for your reply.

I have checked my transformer today, and very 'happy' to see that there are no ratings....there are no papers stating the output voltages....guess they must have purposely removed them.

I suspect that the secondary winding of the transformer(toroidal) has short circuited or melted causing open circuited?
i ran a simple continuity test on a few of the outputs leads.

There are two groups of output wires tapped out from the secondary winding, i ran continuity test between the first "group" of the wires and the there is continuity. However another set has no continuity. But there are some ohm readings....so is there a problem or not?

After thinking back, since it's all winding there should be continuity, but then again why doesn't the another set of wires have continuity.

I think i shall bring it to school and ask my friends about it.

Thanks for all of your advice! Really appreciate it