# Hope this question isn't to dumb...



## menace2society (Jan 26, 2011)

I have a set of Focal Utopia 165 w3 plus two extra 6 1/2''drivers http://www.lightav.com/car/focal/utopia.html left over from my car audio days. What I was wondering was if I could put them in this http://www.parts-express.com/pe/show...number=302-751 and make some home speakers out of them, I remember what they sounded like in my car and was hoping I could recreate that experiences in my home. If possible, what would I need, and could my Onkyo tx-nr 3007 drive them.


Thanks in advance: Menace


----------



## GranteedEV (Aug 8, 2010)

Perhaps, although you will need to modify the crossover a bit for baffle step compensation at the very least else it will would lack midbass and lower midrange unless wall-mounted. You could use the extra 6.5 drivers for this to keep sensitivity high, but will need to buy an appropriate air core inductor (or use a miniDSP and do this actively, but external amps would be necessary).

After making it into an effectively 3.5 way, you would want to measure impedance to determine if the onkyo can drive it sufficiently. Something like this

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=390-804

should do the job

As for the enclosure, being car drivers they may be better suited to free-air, so I would definitely model the woofer and midrange first. They're possibly not going to all-to-comfortable in enclosures by my guess.


----------



## fusseli (May 1, 2007)

What are you expecting to get out of these? If you are expecting a legit top-quality speaker, it's either going to be a lot of extra work or be not worth it at all. From my experience "highend" car audio quality is maybe entry to mid level HT/Hi-Fi even though it doesn't cost much less for a set of speakers.

If you want a decent performer and a straight forward project, that's also a possibility. You'd definitely need to figure out what bass alignment will work best for your speakers, which could help determine what to do with your extra woofers. Then you could add a simple RL passive shelving filter to account for BSC, which would be calculated around the baffle dimensions of those cabs you picked out. If you do that, it'd be nearly a drop-in type of project. I'd guess they'd sound decent, but it's about gauranteed that the response won't be ruler flat. If you have any available fullrange EQ and/or measurement equipment, you could dial it in and flatten it out from there. If you take the time to flush mount the drivers, etc. then it could be a pretty nice looking speaker.


----------



## menace2society (Jan 26, 2011)

fusseli said:


> What are you expecting to get out of these? If you are expecting a legit top-quality speaker, it's either going to be a lot of extra work or be not worth it at all. From my experience "highend" car audio quality is maybe entry to mid level HT/Hi-Fi even though it doesn't cost much less for a set of speakers.
> 
> If you want a decent performer and a straight forward project, that's also a possibility. You'd definitely need to figure out what bass alignment will work best for your speakers, which could help determine what to do with your extra woofers. Then you could add a simple RL passive shelving filter to account for BSC, which would be calculated around the baffle dimensions of those cabs you picked out. If you do that, it'd be nearly a drop-in type of project. I'd guess they'd sound decent, but it's about gauranteed that the response won't be ruler flat. If you have any available fullrange EQ and/or measurement equipment, you could dial it in and flatten it out from there. If you take the time to flush mount the drivers, etc. then it could be a pretty nice looking speaker.


Thanks all for the advise, this is probably over my pay grade. I didn't have any real expectation, I thought it might be something a not so smart guy like myself could handle but I guess not:huh: The only thing I have to disagree with is the quality of sound that can be achieved in car audio. I have had the pleasure of demoing some world class home and car audio systems and the level of SQ in those cars was far beyond mid level HT/Home audio. Focal doesn't put the Utopia label on just any thing. 

Thanks again: Menace


----------



## fusseli (May 1, 2007)

menace2society said:


> Thanks all for the advise, this is probably over my pay grade. I didn't have any real expectation, I thought it might be something a not so smart guy like myself could handle but I guess not:huh: The only thing I have to disagree with is the quality of sound that can be achieved in car audio. I have had the pleasure of demoing some world class home and car audio systems and the level of SQ in those cars was far beyond mid level HT/Home audio. Focal doesn't put the Utopia label on just any thing.
> 
> Thanks again: Menace


Ah, you misunderstood me. I didn't mean to say car audio can't sound good as I'm more than happy with my own endeavors aftermarket car audio. Just compare what you're actually getting with a $200 amp (car vs. HT) or a $200 set of speakers, then if it's not in a nice vehicle to begin with then the $$ is wasted.

I was also encouraging you to try your idea! Let me reiterate.
1) You need to model your Focals in the 1cuft cab to get an estimate of what the lowend will sound like, bigger or smaller might be better who knows. 
2) You'll need to add a shelving filter to compensate for baffle step of putting the speaker in a cabinet. Active filtering via DSP would be ideal since you'd want to use the factory crossovers, but more expensive and would require complicated setup. 
I suggest the method I already described, adding a passive shelving filter. The values of those two compoents would be sized based upon the enclosure dimensions and the intended speaker placement (how close to wall, corner etc). Also, due to the non-flat impedance, the passive fitler won't have perfectly flat response. This means your final frequency response may have some added roughness, but would be 10x better than not having any BSC at all.
IF your spare 6.5" woofers match the woofers in your components, then you could do a 3.5-way and skip the adding additional filter.

The project really could be a piece of cake. Cost would be mostly in the cabinets, the RL components would probably be under ten bucks. If you want to proceed and need help let me know.


----------



## menace2society (Jan 26, 2011)

fusseli said:


> Ah, you misunderstood me. I didn't mean to say car audio can't sound good as I'm more than happy with my own endeavors aftermarket car audio. Just compare what you're actually getting with a $200 amp (car vs. HT) or a $200 set of speakers, then if it's not in a nice vehicle to begin with then the $$ is wasted.
> 
> I was also encouraging you to try your idea! Let me reiterate.
> 1) You need to model your Focals in the 1cuft cab to get an estimate of what the lowend will sound like, bigger or smaller might be better who knows.
> ...


I mite take you up on that if the offer still stands, but I have to warn you I have no idea how to do what you are suggesting :dumbcrazy::help:


----------



## fusseli (May 1, 2007)

menace2society said:


> I mite take you up on that if the offer still stands, but I have to warn you I have no idea how to do what you are suggesting :dumbcrazy::help:


Read this great article if you'd like to better understand what baffle-step is and how it's corrected: http://www.quarter-wave.com/General/BSC_Sizing.pdf

Can you try and look up any thiele-small (TS) parameters of your focal drivers? That'd be what's required to model the bass response. That would also be useful for sizing a zobel filter for the midrange to flatten the impedance, getting a better result from a passive BSC shelving filter. If you want to spend the $$ on the WT3 woofer tester, that'd be awesome, and the more accurate than manufacturer specs (if you can find them!).

The attached image shows the baffle response that needs to be corrected. This is an approximated example for a midrange driver placed right in the center of the speaker baffle, based on the dimensions of the 1cuft dayton cab. IF you took a driver with perfectly flat response and simply dropped it into a box, that's what the response would look like!
As you can see, the low end peels off starting at about 400Hz down to -6dB. An RL shelving filter has the reverse effect, which brings the highend down to match the lows. Again, this can be done via DSP (if you have an analog path to your amp/receiver) or with the passive RL filter whose resutling accuracy depends on how flat the total impedance of the 3-way speaker is.
The ripple before the shelf starts is due to driver size and placement and would be accepted error since we are not redesigning an entire crossover.

Hope this is making sense!


----------

