Hi folks. Here's the story. Just bought my 91Civic and I'm looking to build a decent system around a nice head unit and a Pioneer 10" ported tube-type 200 watt RMS sub. Will replace front factory speakers with 6 1/2" components and rear decks with 6 1/2" 2-ways. Budget for 4 speakers and 4 channel amp is $300-350. While researching head units, I came upon an Optimus detachable face CD receiver for $15 and had some 70 watt 5" 3-way Visonik David 8001 German-made bookshelf speakers hooked up in the back seat just for sound. The cd section didn't work, but the radio and amp section seemed to me to sound rather good for 15 watts RMS and considering the unit- a natural, balanced tone and full soundstage. I thought the quality of the David 800l's had more to do with it than anything. After a month of research I chose the Alpine 7840 H/U and found a new one on ebay for under $100. I installed it and hooked up the speakers and was impressed with the FM reception, features and general high quality of the unit, but something seemed different than the Optimus and not in a good way! It seemed that some of my cds sounded a bit shrill and boomy through the Davids and maybe even slightly distorted. Could it be that I am suffering from "transparency" overload; in other words could I have gotten used to the colorations of the Optimus and now the Alpine's clean delivery sounds foreign to me or.....? I know the 7840 is a much higher quality unit with more power, but I was a little disappointed initially. Any thoughts on this and perhaps a recommendation on front components and amps. Thanks ahead for any ideas. Steveswell
Replies (3)
swez on 04/6/2004 07:51:01
Hummm, these David 800l speakers... are they 8 ohm home speakers? If yes, the Optimus HU may have handled the 8 ohm load better than Alpine which is designed for 4 ohm drivers.
If you look into various features and tone setting on the Alpine HU, you may find too much boost in bass and treble controls can lead to shrill highs and boomy lows. This is usally a result of HU amps going into premature clipping. (a form of distortion covered in our DIY FAQ section)
If you really like the speakers, an outboard amp should improve performance and clean up the sound when set up properly to HU. Also, CD's have a much higher signal level than FM or tape formats. It is very easy to overload the HU amps if the volume is set too high or the tone controls are maxed out. Dial back on the tone controls in your HU to "flat" ("0" boost or cut) and then adjust themjust enough to get a good mix as you dial up the HU volume.
See what that does for your system and come back with your findings OK?
Swez
steveswell on 04/6/2004 15:33:34
Thanks Swez, I think you hit it right on the head! The Davids are 8 ohm, and I think the BBE feature on the HU just exaggerated the incompatibility. I'm not married to the idea of keeping them in the car- they were just filling in till I got some nice components and an amp. Saw much ballyhoo on the CDT products, wondering how sensitive they are to placement and eq issues. The last thing I need is to spend the $ on a highly rated speaker to find out that I've opened a can of "tweaking" worms or my sound hasn't improved at all. Would you recommend rear fills in a Civic, especially if the CDTs produce an extended bottom end? Finally, would I be able to use, say, a USAcoustics 4-channel amp and bridge the rear channels to mono for my sub? Open question to comments from all board members. Thanks for your help. Steveswell
swez on 04/6/2004 20:25:44
There are lots of great options in your situation. The CDT's are very much regarded here as several have bought, installed and love em. At $150.00 a pair for CDT quality... can't beat that.
The CDT's do need amping to get the most from same. The USB (USX) -4085 would be your best bet here as a 4 channel. The rear channels can be bridged and filter for a sub. One thing.... must have a 4 ohm sub when bridged for max power. If you go lower than 4 ohms when bridged, the amp will not last long.
Rear fill... yes, I prefer it in larger vehicles. But many guys like to use Components in front, sub in back, no rear fill as the sub will fill in that gap. Up to you though. Some use the HU rear channel amps to power rear speakers. That's always an option.
Swez
Replies (3)
swez on 04/6/2004 07:51:01
Hummm, these David 800l speakers... are they 8 ohm home speakers? If yes, the Optimus HU may have handled the 8 ohm load better than Alpine which is designed for 4 ohm drivers.
If you look into various features and tone setting on the Alpine HU, you may find too much boost in bass and treble controls can lead to shrill highs and boomy lows. This is usally a result of HU amps going into premature clipping. (a form of distortion covered in our DIY FAQ section)
If you really like the speakers, an outboard amp should improve performance and clean up the sound when set up properly to HU. Also, CD's have a much higher signal level than FM or tape formats. It is very easy to overload the HU amps if the volume is set too high or the tone controls are maxed out. Dial back on the tone controls in your HU to "flat" ("0" boost or cut) and then adjust themjust enough to get a good mix as you dial up the HU volume.
See what that does for your system and come back with your findings OK?
Swez
steveswell on 04/6/2004 15:33:34
Thanks Swez, I think you hit it right on the head! The Davids are 8 ohm, and I think the BBE feature on the HU just exaggerated the incompatibility. I'm not married to the idea of keeping them in the car- they were just filling in till I got some nice components and an amp. Saw much ballyhoo on the CDT products, wondering how sensitive they are to placement and eq issues. The last thing I need is to spend the $ on a highly rated speaker to find out that I've opened a can of "tweaking" worms or my sound hasn't improved at all. Would you recommend rear fills in a Civic, especially if the CDTs produce an extended bottom end? Finally, would I be able to use, say, a USAcoustics 4-channel amp and bridge the rear channels to mono for my sub? Open question to comments from all board members. Thanks for your help. Steveswell
swez on 04/6/2004 20:25:44
There are lots of great options in your situation. The CDT's are very much regarded here as several have bought, installed and love em. At $150.00 a pair for CDT quality... can't beat that.
The CDT's do need amping to get the most from same. The USB (USX) -4085 would be your best bet here as a 4 channel. The rear channels can be bridged and filter for a sub. One thing.... must have a 4 ohm sub when bridged for max power. If you go lower than 4 ohms when bridged, the amp will not last long.
Rear fill... yes, I prefer it in larger vehicles. But many guys like to use Components in front, sub in back, no rear fill as the sub will fill in that gap. Up to you though. Some use the HU rear channel amps to power rear speakers. That's always an option.
Swez
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