MY GF-777Z ** Project Tweeter TUNE **

[Cpl-Chronic]

Well, after listening to the Gf for a few months, I'm starting to understand the traditional 'PHAT' sound people are talking about. Most good blasters have that sweet 80's 'LOUDNESS' sound & mine is more like a juke box on a handle but a little bit muffled in the upper mid. Treble & bess seemed balanced & strong but the treble sounds a bit tinny while vocals are not as full bodied as hoped. After listening to a few different blasters, I can tell that unique 'blaster' sound is in it's own class of 'Hi-Fi' & mine is missing something.

I'm trying a 6db single order cap for the tweeters & the woofers are running full frequency & no choke. The woofers only go up to about 3600Hz before dropping off into distortion so the Infinity tweeters have to fill the gap. I installed 4.7uF caps & they sounded too tinny and only the sizzle came through, so to speak. I need to cover the upper mids/highs with the tweeters so I'm trying a 13uF Bi-Polar cap next. I hope the woofers add more lower mids to the sound too as their natural roll-off will be more gradual, even if a little noisier. I'll also gain some volume back as a good portion of amp power was eaten by coils & pad resistors when I used the sound-stream 2nd order x-overs.

Since they are 4 ohm polymer cone tweeters, I think it'll be safe to try the experiment. We'll see if it works out. I'm hoping to get more of the 2-4K range that adds depth & detail to a recording.

 

[Cpl-Chronic]

Well, after hooking up the new 1st order caps for the twweters, I can honestly say that the sound is more natural & vocals come through somewhat better. The tweeters have a more natural roll-off in the upper vocal range so that they blend nicely with the ESS center woofers. Of course, only a prolonged session with a diverse audio selection will tell me more. So far, so good & stay tuned as I havew to tweak it a bit further. 1 of the caps are letting buzz through but I think it's because it might be too close to the power transformer, maybe? Anyway, I'm sure i'll sort it out tomorrow or on the wknd.

 

[Cpl-Chronic]

UPDATE:

I listened to a wide range of music & sources, like my PC, an MP4 player, Portable CD, etc. After hours of enjoyment, I can say the 13uF caps had a better blending of sound between the woofers & tweeters so that the overall sound was more pleasing but stereo imaging suffered a bit & blurred the soundstage enough to be noticable if you are directly in front of the unit & not more than 5 feet away. The 2-way X-overs were more controlled but had less overall SPL levels because of the wasted wattage.

 

[mendus]

Your "experiences " interest me and I think the sound on my 777 has more bass, my GF 666 ,in comparison, with certainly sound less bass but a more clear, I need to change my woofers, could you make a synthesis of change your speakers and filtering (with references woofers, tweeters and brands).
Thanks.

 

[Cpl-Chronic]

Your "experiences " interest me and I think the sound on my 777 has more bass, my GF 666 ,in comparison, with certainly sound less bass but a more clear, I need to change my woofers, could you make a synthesis of change your speakers and filtering (with references woofers, tweeters and brands).
Thanks.

Well, there are always trade-offs. You have to sometimes sacrafice performance in 1 area to improve it in another. The lower the woofer can go in Hz the less efficient it will be & the more watts it takes to drive the speaker to desired listening volumes. I just switched the woofers around to a new config after adding the caps to the tweeters. The 3.2 Ohm woofers I was using for the center Super-Woofers are now on the outside as they are more efficient by a few db & they have a wider usable frequency range than the ESS woofers I had originally used. The light paper cones, 3.2 ohm impedance & an inverted surround are better at hitting higher Hz while having a warm mid-bass/mid sound for vocals. For the Super-Woofers, I went back to the 6.5" Car Subs that have a deep 38Hz resonant frequency so that bottom end of the bass guitars, synths & drums comes out nice & strong.

It sounds very good for D-Cell audio & I did not have to change the electronics in any way except better caps for the tweeters.

My advice is to get a good set of 3.2 or even 2.8 ohm woofers, if you're brave enough & make sure they are a good efficient paper cone construciton that maximizes your acoustic output per watt. Some people rig home made mounts to convert modern dome tweeters into drivers for the horns. Other members have used 6.5" 2-way car speakers for the outer woofers & good efficient subs for the SuperWoofers. I've heard that sounds pretty amazing too.

Regardless of your end plans, the GF is a modder's dream to work on & built like a tank. I love the design.
Hope this helps. Good luck.

 

[mendus]

thank you for the advice, I'll look for woofers , have you parts numbers to advise me ?

 

[AE_Stereo]

I just turned off the sub-woofer volume controls completely in my GF-909. It sounds to me a lot better than with the "woofers" turned on - even the Bass is better!
The woofers only adds mid tone, to my ears, the main speakers reproduces better bass.

 

[Cpl-Chronic]

I just turned off the sub-woofer volume controls completely in my GF-909. It sounds to me a lot better than with the "woofers" turned on - even the Bass is better!
The woofers only adds mid tone, to my ears, the main speakers reproduces better bass.

Well, when I first got my triple 7 from China, the line in was loose, dirty & didn't work right, the speakers crackled & 1 was rubbing the vioce coil. The tape decks didn't work & it sounded like total disappointment. The speakers make a world of difference in sound quality. With the right blend of drivers, you can achieve quite good results as long as your electronics, controls & speakers work properly. If your bass, treble, volume etc. are dirty or damaged in any way, that will ruin the sound too, of course.

I have gotten 80% of what I wanted by changing out the woofers to a good set.

1 set should be a good car subwoofer with a low Resonant frequency, say 40Hz & a steep roll-off to help rid the sound of that boomy male voice syndrome.

1 set should be a good low impedance woofer with a very efficient paper cone that maximizes freq. range & acoustic output.

I lucked out & a local guy sold me some inverted woofers with a 3.2 ohm impedance & a light paper cone which are quite good for the outer woofers on my Triple7_ZEE. The inner SuperWoofers are now powered by good 4-ohm subwoofer that have a resonant frequency(Fs) of just 38Hz. On low volume they sound cavernous on some tracks & don't muddy the sound with 'boomy' mid-bass.

 

[AE_Stereo]

I just turned off the sub-woofer volume controls completely in my GF-909. It sounds to me a lot better than with the "woofers" turned on - even the Bass is better!
The woofers only adds mid tone, to my ears, the main speakers reproduces better bass.

Well, when I first got my triple 7 from China, the line in was loose, dirty & didn't work right, the speakers crackled & 1 was rubbing the vioce coil. The tape decks didn't work & it sounded like total disappointment. The speakers make a world of difference in sound quality. With the right blend of drivers, you can achieve quite good results as long as your electronics, controls & speakers work properly. If your bass, treble, volume etc. are dirty or damaged in any way, that will ruin the sound too, of course.

I have gotten 80% of what I wanted by changing out the woofers to a good set.

1 set should be a good car subwoofer with a low Resonant frequency, say 40Hz & a steep roll-off to help rid the sound of that boomy male voice syndrome.

1 set should be a good low impedance woofer with a very efficient paper cone that maximizes freq. range & acoustic output.

I lucked out & a local guy sold me some inverted woofers with a 3.2 ohm impedance & a light paper cone which are quite good for the outer woofers on my Triple7_ZEE. The inner SuperWoofers are now powered by good 4-ohm subwoofer that have a resonant frequency(Fs) of just 38Hz. On low volume they sound cavernous on some tracks & don't muddy the sound with 'boomy' mid-bass.

Thanks for the notes. I just posted my observation to say that the original (so called) Super Woofers in 777 only helps to add muddy mid bass. It doesn't make any real Bass at all. Main speakers do that job better!

All the controls in my 909 are well cleaned and I play from external MP3 player with Line-out (Not Headphone level out).

I like to keep my boxes as original as possible and not looking for alteration of components. I have two Midi Stack systems and One full size stack system for quality music listening. Boomboxes are there to see and enjoy. And I play mostly 80's songs without the low frequency drums. There is a charm in the original sound quality of boomboxes as well.

 

[mendus]

Thanks.

I found outer woofers which seem well:

• 6 1/2'' Mid Bass Poly Woofer. Not too big ?
• 30 oz Magnet Structure Weight
1W/1M • SPL: 94dB
• Frequency Response: 60Hz-5kHz
• Impedance: 4 Ohms
• Mounting Depth: 2.5''. Not too deep?
. Fs: 63 hz. A little too high?

your opinion?

 

[Cpl-Chronic]

Thanks.

I found outer woofers which seem well:

• 6 1/2'' Mid Bass Poly Woofer. Not too big ?
• 30 oz Magnet Structure Weight
1W/1M • SPL: 94dB
• Frequency Response: 60Hz-5kHz
• Impedance: 4 Ohms
• Mounting Depth: 2.5''. Not too deep?
. Fs: 63 hz. A little too high?

your opinion?

I acutally had similar specs for my first set of outer woofers. 30 oz magnets are huge tho & you will need to move the transformer if you plan to use them for the outside woofers. If you want them as inside woofers, they need to go lower on the Fs like say 40-50hz. Also, on the outside, you want a woofer that can go hihger too, like maybe 8Khz usabel frequency to blend with the horns & still have punchy mid-bass. Paper woofers with a cloth surround would be best, especially if they have the chrome dustcaps for that 80's look.

Good luck in the hunt. I'm on my fifth combination & refining it further. I'm hoping to go 2 ohm stable with BOSE car woofers on SuperWoofer duty.

 

[blu_fuz]

I would love to hear a speaker modded 777. I agree that these could sound much better but its difficult to mess with a mint one. Maybe ill get another 777 to upgrade.

 

[Ken]

You should go for it if you get the chance, Joe. I did mine right away, the sound was so bad. It sounds great now.

 

[Cpl-Chronic]

Well, after tlistening to hours of music of different types, the new single order caps @ 13uf really open up the sound & everything is just a whole lot nicer sounding. If you can, try 13uF bi-polar caps for the tweeters on your 777Z & run the woofers with no filter at all. It'll give you more lower mids & the tweeters blend with the woofers much better that way. The 12db 2-way crossovers I used were good but not quite right for a boombox. In theory it should have worked but the wasted power in the mids were creating a hole at about 4-8Khz & it sounded a bit harsh & disconnected.

Of course, anny modifications you do, YOU DO AT YOUR OWN RISK. I take no responsibility if you blow tweeters but so far my infinity cone tweeters handle it no problems at all & sound very crisp & balanced.

Cheers,