Speakers/Amp problem

[dj_ooms]

Hi guys and gals,

Been a follower of this forum for about 10 months since I got my Seat Leon Cupra TDI (MK1) but never really posted much. I bought a Becker Grand Prix 7992 almost straight after I bought the car and was happy with the sound produced. I recently decided to upgrade the speakers and wanted to amp them up. I have decided against the sub route as I do not want to sacrifice precious boot space. I therefore went down the route of upgrading the front components and adding an acoustic shelf with midbass woofers in them. I have purchased the following equipment:

SPL Dynamics SD-6.2 6" Components for the front
SPL Dynamics SD-8.1 8" Midbass Drivers in rear acoustic parcel shelf
SPL Dynamics S-4006 6 Channel Amp (4x50W/2x160W + 2x100W/1x320W)

Everything has been installed and I am fairly happy with the results. The Becker does not have any preouts so I have had to buy an mini-ISO adaptor to get them. The fronts components are running on the 2x100W channels on the amp and the rears have been bridged and are running on 2x160W off the amp.

Now here is the issue, the rears are connected to the subout on the mini-ISO and are being used as bass units. These are running fine with using the LPF on the amp. The fronts are not running with any filter, but even with testing to see the bass/midbass output from these, they are not producing much bass at. Can somebody please help me? The front speakers produce way less bass in comparison to the original OEM speakers. From the size difference and reviews I have read, these speakers are supposed to produce some decent bass, but I am confused as they do not seem to be producing much bass at all. Is there a setting on the amp or headunit that I need to change or adjust to get them to produce the lower notes. I have checked all the wiring and everything is cabled up correctly, so I am scratching my head over this. It is my first amp and speaker install but I had a mate helping me who knows his stuff and he's baffled over this also.

Much appreciated for any help and advice.

Ooms

 

[mt audio]

whats all your settings?ie amp,headunit,speakers properly sealed?

 

[dj_ooms]

The headunit is currently running with:

Bass: +4
Treble: +5
Sub: 0
Loudness: Off

The Becker headunit does not have any EQ settings and is very basic apart from that. The settings on the amp, at the moment are:

Rears: LPF ~ 60-70Hz, gain ~ 1/4
Fronts: No filter active, gain at min

The front speakers are connected to the front L/R RCA on the mini-ISO adapter. The front speakers are mounted on 36mm thick MDF speaker rings with Dynamatting behind the magnet. The tweeter is mounted on the plastic above the door panel where the door mirrors are.

The rear parcel shelf speakers are running in an infinite baffle setup as they are midbass drivers not subwoofers so are therefore not sealed. They are running off the subout on the mini-ISO adapter split into two channels then running to the amp.

The rear door speakers are still running off the headunit. The rear door speakers are producing bass as normal and definitely reach 60-70Hz but the fronts seem to cut off and do not produce any sound if I apply an LPF on them with about 60-70Hz. I installed the system on Sunday but haven't really had much time to play with it but I would have expected the fronts to go a lot lower than what they seem to be doing. From the quick tests I have done they do not reach 60-70Hz. I will need to do some further tests to determine from around what frequency they start to produce sound. It is weird though, as all reviews have rated the bass is on these speakers.

 

[mt audio]

those speakers should go down to 50Hz so something isnt right there.have you checked your headunit manual?it may state it will only output to front rca's nothing lower than 70Hz,cant remember off the top of my head

your fine on Hz rating,goes down to 20Hz on CD,30Hz fm 50Hz on MW/LW

 

[mt audio]

also the mini iso converter you bought,does it only have 3 channels or 5,the genuine becker one has 5

start doing some basic tests such as hooking one speaker up to standard ISO wiring vs amp,see if the bass is improved,if not move onto the amp,try a different set of channels.
assume you havent crossed over the + and - for the speakers going from the amp to the speaker as they will just cancel each other out with regards to the bass,as one cone pushes out the other will move in

 

[dj_ooms]

I bought the mini-ISO adapter off eBay. It isn't an original Becker part but is made by Connect2. It has 5 RCA connectors. I am currently running the fronts off the front L/R RCAs and the rear parcel shelf speakers are running off the subout RCA and then split into 2 channels using an 1male-2female RCA adapter. The rear L/R are not being used.

I ran a quick test on the speakers today by disconnecting the rear RCAs on the amp and then fading all sound to the fronts on the headunit. I then used the LPF on the amp to filter the higher frequencies. I started at 400Hz and grudually lowered the frequency and managed to reached about 50-60Hz whilst still hearing sound. The bass being produced was no way on the level of the rear door speakers or original OEMs I had at the fornt before. I have yet to set the gain on the amped speakers; the fronts are currently running on the minimum setting on the amp, whilst I have set the rear parcel shelf speakers at about 1/3 now. The bass from the rear parcel shelf is decent but I just expected a bit more bass up front.

 

[mt audio]

50Hz is as low as they go (same with most comps)
as i said before have you switched the polarity to one speaker of the two?

 

[dj_ooms]

All Sorted

It is all sorted now. I had the mate who helped me install the setup have a look at it. He was positive the speakers were cabled up correctly and didn't really want to pull the door trim off again to have a look. He then asked me if I had increased the gain on the amp to the front speakers which I hadn't done. I increased the gain from the minimum position to about 1/3 and man what a difference. The speakers have really come alive now.

My mate had a good listen to the system and was very impressed with the sound quality. He even told me that the setup sounds better than an Alpine setup he's heard in another car that contained an Alpine headunit, fully amped up with an Alpine amp to Alpine Type-R speakers. He said the SD-6.2 tweeters produce very clear highs and in his opinion were a lot clearer than the Alpine Type-R tweeters. I am very happy with my sound stage now.

Many thanks for the help.