# JBL C508GTi for my PC



## dareo801 (Jan 31, 2012)

I came into a used set of C508GTI's and without a car to install them into i decided to build cabinets and try them inside. These are 12" tall, about .22 cubic feet internal volume, and as of tonight i decided to port them. Crossover is mounted on the back of each speaker. Boxes built with leftover 1/2" MDF and leftover house paint. 

My previous speakers were JBL 4800 towers from the 80s. They sounded good but were huge and had to be located in a less than ideal sound stage. 

Now i have a nearly perfect sound stage and speaker placement. They are powered by a Sony stereo receiver that can provide 75 rms at 4 ohms. On the floor is a JBL Power P1222 in a sealed box getting about 350 rms for sub duties. 

I have never heard anything like these GTis. The clarity of voices blows me away. I still need to touch up the paint on the enclosures but i can't stop listening to music and games on these. They will hit down to about 60 hz before dropping off alot and can hold their own without the P1222 for a lot of music. They could use a lot more power but have no problem getting as loud as i want them on 75 watts. 

I bought these as part of a package deal and had every intention of reselling them. After building these cabinets and hearing them play there is no way i'm going part with these.

If anyone was wondering about JBL component systems or if you can make home speakers out of them, DO IT! I'm very happy with these.


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## [email protected] (Jun 12, 2008)

Nice project. I am looking to so the same kinda. I plan on using the Klipsch 2.1 amp and ditching the cheap speakers that came with it.


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## mrm1776 (Oct 30, 2010)

Nice... For aesthetic reasons, I probably would have chosen to put both of the ports either on the inside or both of them on the outside. It's a little distracting for me to see the ports both on the same side of the speakers.


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## dareo801 (Jan 31, 2012)

Update: I scored a vintage Pioneer VSX 9300 receiver to run my GTis. It's a fully class A amp making 225 watts per channel at 4 ohms. My house lights dim briefly when i power this thing on. I have now unleashed the full potential of these speakers. Crystal clear amazing sound at any volume. Volume no longer has any rational limits. I beg for mercy long before JBL's GTi series does. These can get stupid loud with no distortion anywhere. If you find a deal on some GTis, jump on it. Just don't skimp on the power.


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## stockman2010 (Jan 11, 2010)

that's cool that you set up a little studio setup with DIYMA ingenuity. Hats off, and glad you enjoy them. Don't forget that most of the home audio is rated @ 8ohms. so if the gti's are 4 ohms, you are most likely getting about twice the power to the speakers.


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## avanti1960 (Sep 24, 2011)

nice work, i love bookshelf speakers and have a set of 80's polks that still sound better than 99% of the stuff out there. 

did you ever hear these JBLs in a car? just curious. i'm of the opinion that most if not all car speakers would do so much better a true enclosure as opposed to the leaky metal rattle trap that we try to make into an enclosure.


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## dareo801 (Jan 31, 2012)

I don't own anything that could this size so no i have not tried them in a car. I assume they would sound about the same if they were really well installed in a car. I have grown tired of the "paint i had lying around" color and will be updating them soon. I got just got some carbon fiber vinyl in and plan to wrap these and possibly use the JBL grills. It may be a few weeks as i also need to build my 12 cubic foot w15gti home theater sub. 

I still love these speakers and they will do crazy amounts of volume without distortion.


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## s4turn (Jun 17, 2009)

Nice PC speakers, although you may want to be careful about wiping your hard disks! 
or are the speakers magnetically shielded? (i assumed they wouldn't be, being car audio drivers?)


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## niceguy (Mar 12, 2006)

Fun project...For a few years I was running Alesis M1 active monitors (nearfield) on my computer desk which sounded amazing but too large...been using my old Technics 5.1 AVR, a cobbled together Klipsch quintet speaker set and an old Tangband 740c 8" sub in a sealed enclosure I built w/a Dayton 240w plate amp....

Works great from music or movies (have a pj in the office woot!)..

Have fun!!

Jeremy


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## Kh2456 (Jan 15, 2011)

BeatsDownLow said:


> Nice project. I am looking to so the same kinda. I plan on using the Klipsch 2.1 amp and ditching the cheap speakers that came with it.


How would one do this? I have the 2.1 promedia and want to upgrade.


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## JScherbain (Mar 25, 2012)

nice project. Can I ask how did you go about doing the ports? Is there a process / science to figuring out the diameter, length of tube, placement, shape etc?


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## dareo801 (Jan 31, 2012)

I saw a small cardboard tube at work and thought, "that would make a great port" so i used WinISD model the enclosure. With thiele/small parameters and winisd you can simulate how certain tuning frequencies work. Then its just a matter of figuring your enclosure volume, port diameter and length for the frequency you want. I played with the numbers until i had a nice smooth curve with a boost in the lower end. i want to say my ports are 1" internal diameter x 2" length. My target tuning frequency was 60hz. The enclosures are small and so its very possible my tune is off by hz. Longer ports tune lower than shorter ports. I'm still rocking these speakers everyday with no thoughts of using anything else. My only desire would be to someday upgrade them to C608GTIs if i were so lucky to find some cheap. i designed the enclosure so that i would have enough room to still fit a 6.5" someday.


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## JScherbain (Mar 25, 2012)

Nice. Definitely on to something here, though if I try it I may try without a port at first.


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