advice, 2006 corvette

Hello. This is my first post after spending the last few days reading lots of previous posts. Lots of great information and advice. I am in the planning stages of replacing the factory Bose system in my 2006 Corvette and I have a few things I would like a little advice on. Here's the plan: Kenwood DDX-719 DVD Receiver I am not in love with this unit, but I want to go with a DD and I'm not interested in a Nav unit. I do like the 4v 6ch outputs, and the low SNR on the CD player. Looks like as good a place to start as any JLAudio 12w7ae subwoofer (single). I am hoping this sub lives up to the reputation I've already created for it in my mind. I've had several subs before, but I've always wanted a w7. It's the only thing I've actually bought at this point. I'm planning on building a ported box, if I can figure out how to make this monster fit without giving up the storage space for my roof panel. I will build both a sealed and ported box to JLs specs to use as a baseline, so I can compare how the permanent box sounds. I already have some questions on the box design that will wait for later. JL HD750/1 amp for the sub. This is THE amp JL reccomends for the 12w7, so I'll use it. It's clean and powerful. Front doors. This is where I'm stuck. I have always used 6.5 components with great success, but in my doors I have a 10" woofer factory installed, and I would hate to just run a plate with a 6.5 in it when I have the room. I've boiled it down to an RF PPS4-8 or a Dayton Audio RS225-4 8. They both have good reviews, but the RF has an upper freq response to 5000hz which appeals to me. To fill out the highs I am torn between a 3.5 co-axial and just a tweeter of some sort. I just don't know here. Rear speakers. Not even sure I'm going to run a set. I probably will, but it will most likely be a 5.25 2 way. If I run the 6 speaker set up, I plan on using a JL slash 300/4 (for the mid bass) and an additional 2ch for the tweets My big question is this. How would I cross over the 8s and the tweeters? I can certainly high pass the 8s off the amp at say 200hz or so, but how do I cap them at or below 5000hz, so they dont get muddy? Then the question of a x-over for the tweets. I can high pass a set of coaxials, and be done with it, or use the included crossover in a pair of stand alone tweeters. Any thoughts, ideas and suggestions would be welcome. BTW I listen to my music LOUD. Not so much into SQ, as volume. I listen to metal (Dying Fetus not Metallica)so its not quite as easy to play as rap or country loud. Thanks in advance. Pete

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rj - for the sake of "quality", I too support Alpine. Though a mere user of HUs, I too have a fine taste in music, though more in the hardcore & thrash vein - not the "DC" of Metallica (tho maybe RobT should be back with ST?). And after experience with 2 cheap HUs, I'm back to my old Alpine. Thanks Tommy - I recently selected my intended "current" Alpine replacement model. (FYI - the 2nd-up base CD model; mainly re-chosen for matching audio specs in case I might hear any degradation, and its 20% higher price with the added iPod etc functionality is trivial.) Now I don't have to ask the retailer if anew model is expected. (Though based on present non-employment, maybe the 2013 range is more applicable!)

5000Hz seems a bit high for me. even though the mids might be rated to go that high i think a good tweeter with low range extension will sound better down to about 2500Hz. i listen to almost every type of rock/metal and i find that if you want a clearer, quick sound then it is better to limit your mid so it can focus on reproducing all that lovely heavy distortion guitar and drum. by keeping most of the heavy distortion out of the upper vocal range it should also keep the highs much cleaner on heavy breakdowns and guitar solos. spend your money on a GOOD tweeter and you wont be dissapointed. i know you said you want to focus on loud more than SQ but with this kind of music the two go hand in hand. it takes really exceptional speakers to acurately reproduce music with this amount of complexity and layers. honestly i think that might be the reason that more people dont listen to metal because it sounds like garbage if you dont play it through a good set of speakers.

its very important to make sure that your tweeters can handle these lower frequencies. if they cant then it will sound worse. and i recomend using a quality active crossover to highpass your tweeters and bandpass your mids. a good crossover with variable settings will let you fine tune the crossover point to best match your speakers. i use a kicker KX3, its a solid 3-way crossover and its not expensive. there are better ones but i would stay away from anything audiocontrol.

the JL W7 shouldnt disappoint either but i have limited experience with them. i used to have an 8W7 but that was back in   my rap music days so all i know is that its very loud and very clean. but i dont know how it performs with fast drums and bass guitar. i would guess a sealed box would be better for that sub but ive always been a fan of low tuned ported boxes. i will usually set my sub to be extra loud but then i will set the crossover really low around 60Hz so that the loud bass doesnt drown out any of the highs and will blend better with the mid up around 100Hz. this should give you a very solid punch without drowning out the music.

Thanks for all the input. As far as Alpine goes, I haven't seen one that I like as much as the Kenwood, but I'll check out the latest models. With the mid bass, I agree that 5000hz is a bit high for a speaker that size and I agree that although it "can", that's much different than it "should".... That being said, with an electric x-over, will I be able to low pass and simultaneously high pass the same channel so that the speaker only sees say 200-2500hz? Maybe I'm looking at them incorrectly, but it seems that you can either do a high OR low pass. What you are suggesting is what I want, I'm just not sure how to get there.... One other question, would a pure tweeter or a 3.5" coaxial sound better in this application? I understand that I will probably have to try several different things to get what I want, I'm just hoping for a good starting point. I'll discuss the sub a bit later, but I have my heart set on a ported box (I know....lol). I am going to try both to see which actually works better for me. Thanks again Pete

i dont know about all crossovers but the kicker i use will automatically lowpass the mid at the same frequency as the highpass for the tweeter and then the mid has its own dedicated lowpass. so your example of 200Hz-2500Hz is totally possible. its the exact way i run my system except my crossover is set closer to 2000Hz. my component set came with crossovers but i decided not to use them and use an active crossover instead. it was harder to set up this way but i think it was worth having the crossover point exactly where i wanted it instead of being locked into what the passive crossovers are set for.

Thank you. I looked at the kx3 but I didn't realize it would automatically set the upper freq for the woofer. Another idea I have is this, just to simplify things: The HU has built in x overs for all 6 channels, if I were to hipass the fronts at say 200hz (just a theoretical value at this point), then split the front signal to run my woofers and tweeters off a 4ch amp (jl 300/4), then use the amps x over to cap the woofers at around 2000hz and hi pass the tweets (in this case 3.5 coaxials) at a similar freq (the amp has a 10x adjustment for the x over) each on its own dedicated ch. that way I can balance the two with the gain setting, but still retain the fading (f/r) and not have to add any additional units. Simplicity, not cost is my goal here. Any thoughts? I did some research and found that the technical term for what I want is a "bandpass crossover". I figured there was a more accurate term for what I wanted lol.... One other question, I found a Dayton Audio 8" 4ohm woofer that has a lower upper end freq response of 2000hz. Anyone ever use these? They seem to be pretty popular with the home audio crowd, but a door isn't the same as a speaker cabinet... Thanks again Pete

yea that would work. as long as you can cover all the bases and leave no speaker unfiltered then its fine. and it makes sense because space is at a premium in your vette. i still dont like your idea of using a 3.5 coaxial for your upper range and tweeter but i guess theres nothing wrong with it either, its just strange.

the biggest problem with using home speakers in a car is that they arent over-built with automotive grade materials. the glue might not hold up to weather changes(hot or cold), constant vibrations, moisture, etc.

Ok, I took your advice and scrapped the idea of a 4" coaxial and home grade woofers. I'll be running an 8" woofer (don't remember which one I ordered of the top of my head) and an RF tweeter. I also got my amps: JL HD750/1 for the sub JL 300/4 for the tweeters and rear 5.25s Jl 300/2 for the 8" woofers Now the sub box. I built one each of JLs recommended boxes (sealed and ported) to their specs. But, neither one will fit in the car. I knew that going in to it, so no suprises there, I just want a baseline reference for my final box. If I like the sealed box better, I have no problems. That one will be easy to build. BUT, if I prefer the ported, I have a question about the ports. Based I my design, I can maintain the proper port volume, but I will have to use two ports. Is that a problem with slot ports? I can get the volume by using a single port if I make it look like a 4 chamber maze and I can't imagine how that won't be noisy. Any thoughts? Is it about the volume or the length or both? Thanks

id use the box type that you can make as close to spec as possible, which will probably be the sealed box. small ported boxes usually sound pretty bad as i just found out by trying to put a 15 in my truck when i should be using a 12 considering the space i had to work with. the problem with small ported boxes is that the smaller they are, the longer the port needs to be in order to keep a certain tuning. and a longer port will need more volume from an already small box. so it kind of has a domino effect, smaller box = longer port = even smaller box, and past a certain point its just not even worth it anymore because its the volume of the box combined with the port volume that combine to make the final tuning frequency. also by using two separate ports, they will still need to be just as long if not longer because two ports will take up more overall airspace than just using one.