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Just a small update. Since I last posted here many weeks ago. I started experiencing problems. The bass went from satisfactory to being flat(hear but not feel). I tried tweaking various settings to some degree of success but I came to the conclusion that the box which already had a leak has perhaps deteriorated further in some manner.
Guys, I found time today and got around to buying a new box and having a look at the subwoofer model as well : ).
Post installation in new box, The bass sounds cleaner than before although the 'punch' is still lacking. One can hear the bass but not feel it always i.e. on some notes but not on others.

I think(correct if wrong) I might be under-powering this sub by a whole lot!
I thought my friend gave me some 400 RMS/800W Max sub but it turned out to be this! o.O










Should I invest in 751 EZ mono(750RMS@2Ohms) by JBL instead? As I might get a Sundown Audio SA-12(rated for 600W RMS) in Diwali so pretty sure I will need one then anyways.

Also, Could you or anyone else tell me when powering a DVC with a 4 Ch amp, as I am right now, both Channel A and Channel B must have RCAs connected to the HU Using Y-Splitter to combine them? Currently only Channel A has RCA being fed from HU.

The safe way to drive this subwoofer is in stereo mode (not bridged mode) and to use channel A to drive coil 1 and channel B to drive coil 2. If you parallel the 2 coils, I don't think the bridged amp will drive 2 ohms safely. If you series the 2 coils, the amp will not deliver a lot of power (but will run nice and cool) at 8 ohms. Hence your best option is stereo mode. If you still want to bridge the amp, put the coils in series.

If the HU has stereo subwoofer outputs (RCA) use it in stereo mode. So stereo outputs from HU to stereo inputs on Amp and each channel of amp drives a separate voice coil. I know it is not optimal but this might be your best option. A good mono amp like the 751EZ will make it optimal.

My HU has 3 pre-outs - Front, Rear and Sub. RCA is currently being output from SUB to My Amplifiers Channel A only.
Now, If I've understood you correctly navin, the way it is setup currently not both voice coils are running? i.e. only 180W RMS is being fed instead of the 180W x 2 because only Channel A is connected? even though the wiring from the sub to the + / - terminals are set up as it should for bridged operation?.

Great. Would you have any other recommendations apart from this JBL model.
Also, Does JBL do it's rated power or is it like the Sony amplifiers ratings, which some say are just lies.

Ok, Now I get it. The second voice coil of the sub is not connected at all. Actually that is not bad either. yes you are only using about 60-70% of your amp's power (it will be more than 50% because the power supply of the amp is the limiting factor and since all channels share the power supply you don't really double the power when you send the same signal to all 4 channels or both bridged channels) but it is safe. Do you feel you need more power? Or higher bass SPL?

Now here's an idea I only tried with a stereo home power amp and a Focal dual coil midwoofer - it might work for your amp.

I connected 1 channel of the stereo amp to coil 1 of the woofer. The second channel was fed a LP 1st order 300Hz PLL (Passive Line level) signal. Hence the second channel was only producing freq below 300hz but with a rather gradual slope (6db/octave). this second channel was connected to the second coil of the woofer (in my case a 7" Focal). The object here was to compensate for bass cancellation due to the baffle step.

Now lets try this idea with your woofer.

Channel A is 80hz fixed. Channel B is 40-500hz variable. You could feed Channel B to the second coil and vary the crossover of Channel B. This way you can fine tune to bass output of the sub. My guess is you might like filter of Channel B at around 40hz (but tune to your own taste). This means your woofer will see a little boost in power at 40hz (or whatever frequency you choose with Channel B). My suggestion is not to exceed 200hz with Channel B.

As far as amps are concerned. There are a few good monoblocks out there. JL Audio JX500/1, Kenwood X500-1, Pioneer GM-D8500M etc.. all are pretty decent.

Thanks I'll go google these.
I think my subwoofer is unde-rated though navin. Although it says 750W RMS on the spec sheet it should handle 1000W RMS. Perhaps I can get some recommendations by you for 1k RMS mono blocks as well please : ).
My future SA-12 can handle 1-1.2k RMS on daily use as well, I've been reliably informed.

There is no kick/punch as they say right now. I can hear the bass but not feel(vibrations)it unless bass settings is turned all the way up which results in boomy like distorted bass.
My very old setup of a Sony 222 to a 600W free air Pioneer subwoofer in my old esteem used to give a better punch than my current setup, which is very annoying to me >.<.

I should mention something that happened few weeks ago. While I was tinkering with the LPF/HPF on the amplifier. I accidentally ended up setting one to LPF 80Hz and the other one completely OFF. I did not realise this on my drive back home untill I started hearing the Subwoofer completely shut off on some bass notes and on some making 'popping' noises. So the proposition of experimenting like this is very scary to me. I do not think I'll be doing this.

Question, Can't I just use the RCA Y-Splitter to feed signal to activate the other voice coil as well? The installer told me not to do this as the amplifier isn't "powerful enough" to handle this sub. I thought he was being a liar as he really wanted to make a sale on a mono block, was he telling the truth? or safe to do it?

If the amplifier is not powerful enough it will just give up (you will hear that too but it wont destroy your sub).

Yes you can use a Y splitter but like I said earlier the gains are marginal. You will gain about 2db more SPL. The limitation of the amp is the power supply which is common to both channels.

Use one channel. the one with a variable LPF. Set the LPF to 200hz and listen. The subwoofer should be connected to only 1 bridged pair channel of the amp. The punch you are missing is actually not bass but mid-bass. At 80Hz/12db there is not much midbass, at 200hz a lot more.

If the amp has a subsonic filter (a HPF set at say 20hz) turn it on. It will prevent the distortion you are getting.

So the kick/punch can be restored through careful tuning much of this is trial and error. A free air sub like your old setup may have more kick but will have less definition in the bass so don't rue that set up. Your current set up can be tuned to sound as good if not better.

Lastly I don't think you need 1KW. Your subwoofer may be THERMALLY rated to 1KW but the PHYSICAL limitations from the suspension of the woofer will limit the woofer before that. A good 500-600W amp (true rms 0.1% distortion etc..) with a beefy power supply will do well.

I suggest dont waste time and money on this sub by investing on a 1200w amp (751 EZ mono), instead get a new decent sub for the same price and use the existing 4channel amp to power it (or buy a suitable amp) and you will be happy. Do you think this sub can handle 2000w RMS and give you a good bass, leave the current condition, it would miserably fail even when it was new.

CMS, I think Maky is getting a new sub soon. He also intends to get a monoblock for this new subwoofer and might then use the 4 channel for front and rear speakers only.

In that case what about the main 4 channel amp as it is no way comparable to the monoblock, it will be a big mismatch unless the main amp is replaced with a better one than the pioneer amp. I would give more preference to change the main 4 channel amp which powers the components than the sub amp. Even if I have a budget constraint in changing both the amps, I would go for a good 4 channel amp for the components and use the existing amp for the sub, everything depend on the OP's personal preference.

CMS, agreed that a JL 500/1 is a better amp than the Pio 6604. But since Maky was getting a subwoofer he'd need a monoblock. The 6604 would not adequately drive the Sundown woofer. Hence if he upgraded the 6604 to a better 4 channel amp, he'd still need a bigger amp to drive the subwoofer.

For all except the most demanding of applications the 6604 will however adequately drive the front and rear speakers. Yes there are better 4 channel amps out there but Maky's budget did not allow for an upgrade of he 4 channel and a dedicated monoblock.

Since the monoblock was more or less mandatory (given the 6604's limitations) he decided to get the monoblock. The other choice would be to get a 4 channel amp that is capable of being used as a subwoofer amp in bridged mode (for 2 channels) and use the other 2 channels to drive the front. Most such 4 channel amps (capable of delivering 500W rms clean with adequate headroom etc.) would be more expensive than monoblocks like the JL Audio JX500/1, Kenwood X500-1, Pioneer GM-D8500M etc..

I meant adding a good mono block and a good sub in to a non matching setup, the end result will be a sub dominating setup, all you hear is a nice bass. My point was to get the basics proper (main channels) before anything else. It will be a mismatching setup as either the sub cannot perform at its potential or a sub dominated setup. Adding that mono and Sunfire sub would have been better if the mains were able to match with that else go for a proper matching sub. By making a section in an audio chain "better" will not give a better overall output. Its my view point.

CMA sir, you have a point but...Maky already has 4 speakers, a 4 ch. amp, and will be getting the Sundown (not related to Bob's Sunfire) sub in a short while. We are trying to make do with what we got.

Sure, his Sundown MAY outperform his current front speakers but that's the hand we have been dealt. If we had to upgrade the front speakers and get a better 4 ch. amp we need a bigger budget.

I was just trying to make OP understand about this "unnecessary expenditure" if there is a chance or a "possible upgrade", but I had to use 3 or 4 posts to explain.:)

Thanks for your input CMS.
Navin is giving me advise based on my current situation but you are correct. I will possibly be upgrading front comps and rear 6x9s to something sexier in Diwali, If budget permits : ).


Hmmm this did happen that day when I was at the installer. He put both channels on and turned volume up to 20(I listen on 15 normally) and it just shut off. No Issues at volume 15 or lower.

Navin in my HU there are settings for LPF and HPF but the LPF only goes up to 120Hz If I remember correctly or one level above that but I'm certain it doesn't go up to 200Hz.
If I do setup the LPF(currently set as OFF) on the Amplifier to 200Hz but the setting for LPF is set to it's highest possible 120Hz or so on the HU end wouldn't it still limit it at the lower 120Hz?.

Sadly no subsonic filter.

Do you mean wiring by that? because my system runs on stock battery and alternator. I read nothing beyond stock required for upto 1000RMS when it comes to Battery and alternator.
If wiring, What would I require? 4 gauge wiring?

I prefer to use the XO in the amplifier as many HUs lose their settings when the car goes for service. So you can set your HU to All pass and use XO of Amplifer only. But yes your understand is right if say the HU is 120Hz/12db and the amplifier is 200Hz/18db then the effective electrical slope will add will be 120db/12db till 200Hz after which it will be 200Hz/30db (12+18).

I am talking of the amps power supply not the car's. The area where most amps skimp is the power supply. Many amps may be rated to 50W rms x 4 channels driven (20-20khz, 0.1% dist, etc....) but when you try to drive all channels to 50W they give up because the power supply is 120-150W and runs out of steam. Unfortunately most companies don't document this so we have to rely on experience and current reputation of the company's products.

JL for example is pretty good about their power supplies. For a subwoofer a Class D amp makes a lot of sense and the limitations of Class D (mostly sonic) are not noticeable sub 200hz.

Yes a 4GA kit will help a lot. It means you lose less power in the wires and more is available at the amp.