[the_diyr]

Ok the drivers and crossovers are all messed up in these ..The 15 inch woofers appear to be in good shape as does everything else they just sound awful.. So I did som enclosure calculations on this three way box , it has enclosed mids and tweets that take up hardly no space in the enclosure .. The enclosure in cubic feet is 2.648 ft³.. So the port in these is 5 inches long by 2 inches round.. So I did some calc's and came up with a low freq somewhere in the neighborhood of 23-24hz.. Wow..My only problem is the crossovers that were in these do not work .. .. So I am lookin at replacing the tweets , the mids and I guess the woofers.. Biggest thing that gets me about the 15 inch fisher woofers is with a real bassy song they produce great bass but they barely move.. I guess if i replace the woofers I will get better sound because these speakers are at least 25 years old.. I got them at a garge sale years ago for 12.00 for the pair.. They are 27 inches tall , 17 inches wide , and 13 inches deep.. 8Ω

 

[the_diyr]

:dontknow:Here are some crossover ideas if i build my own.. What was normal for the speakers that were in the cabinet was 1.5 - 6 khz... So I used the calc for first order , and fourth order .. Not to sure but 1st order has no gain and 4th order has a 2.99db gain but it will be a monstor to build

 

[the_diyr]

http://www.diyaudioandvideo.com/Calculator/APCXOver/

This is the calculator I used

Capacitors
C1 = 3.31 uF
C2 = 29.88 uF
Inductors
L1 = 0.19 mH
L2 = 1.7 mH


750 to 6000 here

 

[the_diyr]

Here is a humdinger 4th order 2.99db gain

Parts List

--------------------------------------------------------------------------------
Capacitors
C1 = 1.77 uF
C2 = 3.51 uF
C3 = 22.24 uF
C4 = 31.42 uF
C5 = 4.71 uF
C6 = 1.05 uF
C7 = 41.92 uF
C8 = 9.48 uF
Inductors
L1 = 0.13 mH
L2 = 0.59 mH
L3 = 0.84 mH
L4 = 4.8 mH
L5 = 0.39 mH
L6 = 0.18 mH
L7 = 3.18 mH
L8 = 1.6 mH

4th Order Normal Polarity

6000 Hertz / 750 Hertz

8 Ohm Tweeter / 8 Ohm Mid / 8 Ohm Woofer
2.84 db Bandpass Gain, Spread = 8 : 3 octaves

 

[the_diyr]

Ok this looks like the verdict .. I am going to build my crossovers.. Getting the goods from madisound.. I figured it out on a sheet of paper but the photo shows the idea .. Total cost for mid line caps and inductors is about 23.20 per ( Speaker ) Crossover so 46.40 for the pair..:yikes::clap:

I just hope I picked out the right types Went air on the Inductors and poly on the caps....

 

[the_diyr]

Cost per each and speaker size

 

[the_diyr]

Is it just me are did Caps and Inductors really jump in price .. Just doing some figuring for a 3 way crossover .. ( 1ST ORDER ) I am looking at 18.00 a 3rd order Normal somewhere in the neighborhood of 40.00 per each ... I am seriously considering these

http://www.parts-express.com/pe/sho...w=1&&vReviewPage=2&vReviewRand=473751#reviews

 

[the_diyr]

Found some crossovers 800/5000 I ordered them .. 3 way...

Found some nice 3 inch tweeters polycell , just like my center channel has

and polk audio 5 inch closed back midrange.. Will finish these next week

 

[the_diyr]

I am debating as to what to do with the front setup...First I thought about building a shelf system around the big screen tv.. But that was sort of shot down by the wife.. I think she sai we dont need anymore clutter in the den..So then I thought maybe build some tall and less wide front speakers .. My biggest problem is the width of the room . My right channel front is just fine but my left channel front is almost behind the couch..and the sub is right on the floor too.. bothe behind the side of the couch..

 

[the_diyr]

Ok I have the crossovers on the way for the ST-828's that merely came with a junk setup for the actual crossover network.. The 15 inch woofers are in good shape even thought they are ugly as .. Now the mids and tweets are all screwy one speakear has the original tweeter and midrange and the other has a slightly smaller tweeter and a slightly larger midrange that was rigged up in the cabinet before I got them.. So I need tweets and mids both closed back design.. Just dont have the cash to get good tweets and mids now .. So I guess i should wait to put the crossovers in..

 

[the_diyr]

yep I thought about buying ne speakers for the front but most of the new stuff is overpriced plastic junk. I went to best buy and asked the store manager if they had any floorstanding speakers that were made out of real wood .. He laughed and said I dont think they ever made speakers out of real wood... If I cant get the Fisher speakers like I want them I will probably build my own new ones.. I did listen to a few sets of cheaper floor speakers and nothing really struck me as too the type of sound that I wanted.. I even listened to bose at a dealer in town and at very low volume they sound good but when you turn it up it sounds like my grandmothers old am transistor radio... I always knew bose was for old people who didn't know what sound quality was.. Well I think the crossovers will be here today I hope.. And I think the surround repairs for the RSVIDEO center channel will be here tommorrow

 

[the_diyr]

Ok I ordered some soft dome tweeters for the fisher's to match what is in the RSVIDEO center channel .. Fluid cooled soft domes... I hate waiting on stuff to show up in the snail mail..

 

[the_diyr]

Pretty close but I ordered th Cerwin Vega crossovers .. I used a crossover calculator , volume calc is right on the money .. Using CV tweets CV Mids and CV woofers.. The 15 inch woofers are CV's from an old set of speakers.. The cabinet size is perfect for the drivers.. the tweets are closed back , the mids are closed back.. the crossovers are the same specs as what is on the fron of the fisher cabinet



a modest 1.2 -6.0 khz

 

[the_diyr]

I noticed on all the speakers that are mounted in the ST828's there is no seal.. They are all just mounted to the wood.. I was thinking when I put all the drivers back in i am going to use some rope caulk or something to really seal the speakers good .. I used this on my custom under the seat sub box I installed in my crewcab and it makes a good seal..

 

[the_diyr]

Closed cell foam tape is a good idea .. On the silicone thing I heard that it might hurt your surround foam from the fumes .. not sure though.

 

[the_diyr]

Well the UPS guy just showed up a few minutes ago with my new Cerwin Vega Tweeters .. So now the ST828 build is going to happen ... Now after a ton of measuring and figuring the old ST828 enclosures I am pretty sure I can make the tweets mids and 15 in woofers work just fine.. Basics are 15 inch CV woofers ( 5 inch CV mids ) and 3 inch CV tweets.. The tweets and the mids are closed back .. Leaving me a cabinet 27 inches tall by 12 inches deep by 17 inches wide.. Port is 2inches dia. by 4 inches long. Box volume is 3.18 .. tuned at about 45hz or close.. May play with the port a little ?? the drivers are the same size as the old fisher drivers .. I am using the CV crossovers as well.. they are 3 way.. I think it will work .. I have played with box and port calcs. before when I designed my 10inch pioneer ported under the seat box for my Ford Crewcab FX4.. Will see tommorrow , If my wife will allow me to work on them tommorrow I meant..:rant:

 

[the_diyr]

Here are the tweeters and the mids that are going in the fisher cabinets. along with the crossovers.. Just trying to decide about the fisher 15's still in the cabinets , they seem to be in better shape than the 15 inch CV's that I have.. The CV's nead refoaming .. but the fishers do not..

 

[the_diyr]

They are built // The crossovers were mounted as were the tweeters and mids .. My old fishers sound great.. The cut off points are very smooth.. The tweeters are not the dome type that I wanted but money is a little tight The crossovers that we feared would sound bad actually sound really good .. Now I really want to build some speakers so I am thinking start with something simple like the rear surrounds... Also I still have to build my equipment rack..

 

[the_diyr]

Ok they are ugly bu they sound great

 

[the_diyr]

I know the woofer looks like cr** but it sounds good.. Actually I have never be able to make those 15 inch woofers even begin to move .. I tried one time and got my Pioneer A/V reciever pretty loud and still nothing , they do vibrate a little bit ... Maybe one day I will build some better fronts but for now they sound great .. The RSVIDEO infinity that i rebuilt the surrounds is set to small on the A/V reciever and it works great since it is set to small it has no bass at all so it sounds good.. I did have to set the fishers to large and then this made the sub go to plus .. Which all sounds good ... the only thing i would change if I could afford them is maybe replacing the cv tweets that i bought with some ribbon tweets , the only problem with ribbon tweets is they are overpriced for what they are and the power handleing isn't very good