GlassWolf

Running fully active means that each speaker has it's own amplifier channel, and an electronic signal processor is being used to control crossover points, cut/boost, and usually, the Q for each speaker. This is superior to using components with crossover modules and passive filter networks because with digital signal processing, you have full control over time alignment, XO frequencies and slopes, and power to each speaker. You also avoid the issues of phase shift and the induction of noise into the system with passive filters. Active is also more efficient as you don't lose power across the filter networks. Active is really superior in every regard other than the cost and space required. You'll need an amp channel per speaker, adeqate power to do so, and the money and space for those amplifiers and signal processors.

I'd like to get my paws on a DaVinci one day. I just like the look of that old amp. Anyway if you want remote bass control without the worry of clipping your amplifier signal, the way to do that is with an attenuator that allows you to remotely reduce the bass instead of boosting the voltage of the input signal. Ideally, that would be a better solution for a remote bass adjustment with a factory head unit.

no bass boost. use one or the other, but not both the head unit and amp crossovers. combining the two causes the slope to be cumulative, and messes with the settings. I would start with the LPF @ 50Hz, and HPF @ 100Hz. You can adjust from there, but it's a decent starting point. the 1 octave gap will be filled in by the roll-of from both the mids and the subs. amplifier crossover settings The above link illustrates what I mean with the gap between HP and LP filters.

I used to see this on old Alpine CD players (7903 era) and it was caused by the sensor that told the player there was a disc inserted going bad. In any event, if a can of compressed air in the CD slot (with the included straw) doesn't blow out the dust causing the problem, then it's time to send it off to an authorized repair center. The 880PRS is a really nice deck. I loved the styling on that model.

for components, I'd use a HPF set to about 125Hz typically. Any higher and you're blocking more than just bass. I'd also use the amp, had unit, or custom built 2nd order filters. The "bass blockers" sold on sites like crutchfield are first order 6dB fliters, and are pretty much useless and overpriced. Not all amps have built in crossovers, though. The old Orion and PPI amps, and RF for that mater, did not have any sort of built in features, other than internal bridging on the upper lines from those companies.

yes class D amps run cooler and draw less current, but this could be another problem, like a bad ground, an inadequate electrical charging system, or the gain on the amp being turned up too far.

...that's not a moon, it's a space station! (I couldn't resist)

a bass knob works in one of two ways. 1. a remote gain adjustment that laters the impedance of the input stage of the amplifier 2. (most common) a remote amplitude cut/boost (voltage) adjustment to a fixed (or variable) frequency point with a fixed Q (slope.) It's like a remote EQ slider. The Epicenter is a digital bass restoration device. You send the Epicenter a full range, uncrossed over signal. The epicenter looks at this signal and computes, based on higher octaves, what it believes should be present in low frequencies. If bass frequencies are already present in the source material, the Epicenter won't add anything. . It uses some subharmonic algorithms to figure out what it thinks should be present in the low frequencies based on what it sees in the higher frequencies. You choose on the Epicenter what range of frequencies you want to adjust, both the center point and how wide of a range to adjust. That is done on the unit itself with 2 knobs labelled 'wide' and 'sweep'. Directly from Audiocontrol - "The Sweep knob allows the user to pick the center frequency of the bass restoration. With the Sweep knob turned all the way to the left, The Epicenter® is centering restoration on 27Hz. With the Sweep knob turned all the way to the right, The Epicenter® is centering on 63Hz. The middle position represents approximately 45Hz. The Sweep knob can be set to center The Epicenter®'s restoration anywhere between 27Hz and 63Hz. The Wide knob allows the user to control the width of the restoration. With the Wide knob turned all the way to the left, bass response is tighter and harder hitting. With the Wide knob turned all the way to the right, the bass response becomes more booming and open." Once you've tuned the unit to 'boost' (create) bass in the right frequency range, you then adjust how much restoration you want by turning the knob that is mounted in the front of your vehicle. Because the epicenter takes an uncrossed over signal to work correctly, you must cross over your signal AFTER the epicenter, which means if you are using crossovers on your head unit, you'll need a full-range output for the Epicenter, or you'll need to switch to an external crossover. Along with this digital bass restoration, the epicenter functions as a line driver, yielding up to a 10 volt output. It supports both balanced and unbalanced inputs. You can make ANY music absolutely thunderous with the epicenter. You can also drive your amplifier into HARD clipping EXTREMELY easily if you do not know what you are doing. The Epicenter is a bass-head's toy, not much more. Using it on some music results in muddy worthlessness. Using it on other music results in sickeningly deep, punchy and consuming bass. It's hit or miss, and you only get to tune the frequencies in which to recreate bass on the unit itself, so you can't tweak it for each song. You've just got the ability to turn it 'off' or adjust how much it recreates by turning it up. It's a glorified parametric EQ merged with a harmonic bass restoration device. Read the manual for some pretty pictures showing what i described Epicenter manual A parametric EQ allows you the following adjustments over the number of bands specified on the unit: Cut/Boost - (as described, raises or lowers the amplitude of the signal) Frequency center - (picks the exact frequency to adjust. not fixed points like an in-dash slider EQ) Q/slope - how quickly (sttep or shallow) the signal rises or drops back to the unaltered amplitude in either direction beyond the frequency center point being adjusted. these 3 settings are available for each of the bands on a parametric EQ. (example: Alpine 3401 and 3402 7-band EQs, retired models) An alternative to a parametric for system tuning is a 1/3 octave EQ, which offers 31 bands from 20-20,000Hz, with a fixed Q, and variable cut/boost at each frequency. (example: AudioControl EQT)

Perry is a great guy. I own both his repair CDs, and his website on CD. Well worth the cost, if for no other reason than to support his work. You will need tools for this type of work though, and I can tell you first hand, that the tools are not cheap. A few tools off the top of my head that you'll need are: True RMS digital multimeter signal generator high current regulated DC power supply oscilloscope with various probes the actual schematics for any amplifier you plan to repair, most likely a high-current resistive dummy load variable wattage soldering station (weller is good)

Impious, if you would care to add to, or correct that article, I'd be more than happy to add your thoughts to the page. I wrote that link to help folks, and answer commonly asked questions I've seen over the years to save having to re-write the same answers over and over again on forums. I'm always upen to input from people. Let me know.

this. also try this if you want fast and simple: flared port/aero port calculator

nice looking welds.

for a speaker enclosure, you'd want a material that has high density, low resonant frequency, and is resistant to flexing. You want something as inert as possible, acoustically. Any flexation in the enclosure will color the output by altering the volume of the enclosure. Any resonance in the enclosure can cause harmonics and color the output. A good material (without being impractically havy) is birch plywood. If you want to see esoteric and expensive, take a look at the Krell Master Reference subwoofer. 1" thick aluminum billet enclosure, 2600 watts, and a pair of TC Sounds 15" subs.. for home audio.

That was simply written to illustrate the reason not to set your crossover points to the same frequency for HPF and LPF, which most people initially try to do, which in turn causes warm spots. If you want the more in depth version of how to set up a soundstage, this would be that article. My link Acoustics are a science. Everything that happens in a car, a room, or a field can be explained. Rules have their place. If nothing else, it's a good starting point, which is exactly what I stated that link to be. A place to start.

things to check: *amplifier ground to bare chassis metal *amplifier gain setting (too high will cause the amp to clip. severe clipping can send an amp into protection) *voltage rails sagging (check with a DMM during use) due to lack of current from inadequate cahrging system. *voltage drop from power and ground wire being too small for the current load + run length *amplifier presented with too low of an ohm load by the connected drivers, causing amp to go into protect from over-current

ah OK for some reason my brain was thinking "seat bolt" not belt bolt, but in any event, with the bench out, and using the rear seat belt bolt, yeah. Not really an issue if you've stripped the paint from that area to get a solid connection.

charging system notes

the part about XS and Kinetik? Fair enough. I was just an opinion. The problem with Kinetik's web calculator is that they don't account at all for the efficiency of the amplifier(s) in question when figuring battery life based on wattage. It may not sound like a big deal, but when amp efficiency can range from 50%-85%+ and we're dealing with well into the 4 digit range for wattage, and well into triple digits for current draw, it can matter. Anyway, for what it's worth I'm using Kinetik 2400s now, myself. By no means are they "bad." I just prefer the XS products, given the choice.

well im looking for spl but im not looking to enter any comps...so basically the loudest it could possibly be while still being a daily driver Crossover setting basics link read this plaese. set your sub's LPF to 50Hz, 18dB slope. Set your HPF for components to 100Hz, 12dB slope. See how that sounds to you. Worth a try.

safety issues since those bolts are there to hold the seat in place, and because if the seat does shift at all from having the ring terminal there, it can cause a faulty ground point. It's a location that can get kicked if you have a back seat as well. Things like that. It's also possible to catch the ground wire with the seat rail when you slide the seat to position it, which can pull out the ground line from the terminal... blah blah.

I have to agree that a BTL in a ported box tuned to 33Hz isn't designed for midbass. That LPF should be set to 50Hz, so that sub stays tight and hits hard and deep, like it's meant to do. If you want midbass, try using 8" midbass drivers from someone like DynAudio, Seas, or Vifa. Then you can use them as rear fill too, and add a L-R differenced signal delayed about 20msec and band-pass filtered. That would be an outstanding addition to a sub and a 2-way component set up front.

thank you.

a few links that might help you out some in designing your charging system: My link the pages under the Electrical heading below Amplifiers.

it's not abnormal for amplifiers to be hot to the touch. That's a side effect of producing that much power output. A fair number of alpine head units are 2 volt pre-out models, although I don't know for sure on yours specifically without looking it up. in regards to the amp fading out on you, it sounds like the amplifier may be damaged, but if it works @ the 2 volt setting, then yeah just leave it there as long as the amp is not clipping. On using the seat bolt as a ground spot.. I usually advise against that. It's not a good place to use unless you're just really adamant about not putting a bolt into the floor pan or trunk floor of the car.

so they discharge equally. Has to do with the Peukert Number for each battery. see here: battery calculator I also feel the XS batteries are superior to Kinetik, IMHO.