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KPT-904 Build


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Just arrived home with my 904’s!  They are bigger than I was expecting, but I like them.  510s are on the way & thinking of having Crite’s sort out the crossovers since I am not sure how to make everything work together.  Who is the person who builds metal grilles for them?  

A802492C-8261-46DC-A517-DD3B6ACAF5C8.jpeg

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29 minutes ago, Amphicar said:

Who is the person who builds metal grilles for them?

Message @jason str

 

For reference, these were from my KP450's which I believe are the same dimensions as the 904's (These are factory made)

 

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1 hour ago, Amphicar said:

Who is the person who builds metal grilles for them?

CONGRATS on your 904's! No clue on metal grilles, but with shipping it could become cost prohibitive :( But grilles are easily made. Just get some 1/4" or 3/8" (??) MDF, and cut them to size - about a 1/4-3/8" smaller than the box. Cut out speaker holes and port holes. Cover with cloth - Crites has original heritage cloth; well worth it. If needed, get some Duratex to make the speaker boxes look new.

 

Also suggest boxes for the K-510's - especially since I do not think you have the brackets. Made mine out of 1x10 pine (easier than cutting "big" 4x8 sheets). My boxes are approx 18Wx11Hx9+D inches. If I had to do it again, I would make them the width of the KPT-904 :) 

 

One more ... re xovers ... haha; you never know ... xovers (if there are any) are INSIDE the box with only a connector block on the outside right hand side. Take out a driver (top one ??) and check. Good luck :) 

 

 

IMG_2009 - Copy (2).JPG

 

note; old pic ... everything has changed except the 904's :) 

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55 minutes ago, TasDom said:

MbijtfB.jpg

OK, so factory ones only had a metal grille over the speakers ... if @Amphicar "just" wants the speakers protected (instead of a "full" metal grille, guess he can just cut some and glue them on :) But; think we loose a couple of dB's with this.

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1 hour ago, Emile said:

CONGRATS on your 904's! No clue on metal grilles, but with shipping it could become cost prohibitive :( But grilles are easily made. Just get some 1/4" or 3/8" (??) MDF, and cut them to size - about a 1/4-3/8" smaller than the box. Cut out speaker holes and port holes. Cover with cloth - Crites has original heritage cloth; well worth it. If needed, get some Duratex to make the speaker boxes look new.

 

Also suggest boxes for the K-510's - especially since I do not think you have the brackets. Made mine out of 1x10 pine (easier than cutting "big" 4x8 sheets). My boxes are approx 18Wx11Hx9+D inches. If I had to do it again, I would make them the width of the KPT-904 :) 

 

One more ... re xovers ... haha; you never know ... xovers (if there are any) are INSIDE the box with only a connector block on the outside right hand side. Take out a driver (top one ??) and check. Good luck :) 

 

 

IMG_2009 - Copy (2).JPG

 

note; old pic ... everything has changed except the 904's :) 

Good idea on the MDF.  I can’t decide what I want to do- redo Duratex, veneer, or paint a color like the Frankensteins.  Could impact my choice… I might take your idea on the boxes, he gave me some JBL brackets I might modify at first.  
 

The crossovers are inside the boxes with connector plates outside.  How do I know if I can use the crossover without modifications? 

C56AAB71-826B-415B-9DAE-CD97EEE8C7F5.jpeg

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27 minutes ago, Amphicar said:

The crossovers are inside the boxes with connector plates outside.  How do I know if I can use the crossover without modifications? 

C56AAB71-826B-415B-9DAE-CD97EEE8C7F5.jpeg

Your connectors look much nicer than mine :( I just have a terminal strip with "input" and "HF out."

Note; your sticker says KPT-904-LF-N. Same as mine so I assume the Xover is identical also :) Pic below is from my 2nd KPT-904 ... maybe check if the crossover is the same.

 

So; assume (yes a$$-u-me) the bottom connectors are the inputs and the top if the HF out.  If you have an oscilloscope (and know how to use it :) ) you can measure the (?) HF out. Or with a mike and REM software you can do the same - after you connect a speaker to the (?) HF out.  I would just put your amp on the input and hookup a cheap speaker to the HF out. Stock they are supposed to cross at about 850-900Hz; you should be able to hear this with your test speaker :) 

 

Hope someone can shed some more light on this.

IMG_1998 (2).JPG

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40 minutes ago, Amphicar said:

I can’t decide what I want to do- redo Duratex, veneer, or paint a color like the Frankensteins

Yes; wanted to veneer mine ... but very difficult to do since the edges are rounded ... so; just did a coat of Duratex and even my wife approved :) 

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29 minutes ago, Emile said:

Your connectors look much nicer than mine :( I just have a terminal strip with "input" and "HF out."

Note; your sticker says KPT-904-LF-N. Same as mine so I assume the Xover is identical also :) Pic below is from my 2nd KPT-904 ... maybe check if the crossover is the same.

 

So; assume (yes a$$-u-me) the bottom connectors are the inputs and the top if the HF out.  If you have an oscilloscope (and know how to use it :) ) you can measure the (?) HF out. Or with a mike and REM software you can do the same - after you connect a speaker to the (?) HF out.  I would just put your amp on the input and hookup a cheap speaker to the HF out. Stock they are supposed to cross at about 850-900Hz; you should be able to hear this with your test speaker :) 

 

Hope someone can shed some more light on this.

IMG_1998 (2).JPG

He actually had both types, yours with the strip inputs and mine with the built in banana jacks.  Fortunately, he also had both types opened up and the crossovers are the same in both.  Also, I read the numbers on your crossover & all the numbers are the same.  I forgot about the rounded edges, perhaps duratex will do until I can afford something more drastic.  All looks the same with your eyes closed, as they say.  I do not have an oscilloscope, and am not quite sure what you mean by the next part.  Excuse my ignorance, electronics are not my strong suit. Thanks!

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20 minutes ago, Amphicar said:

not quite sure what you mean by the next part

Just rambling about a microphone and REW software. That's how many of us measure our speakers (and room).

 

So; just hook up a speaker to the HF output. You should be able to hear "only" about 900Hz and up. All the lower bass and some of the lower midrange should be gone. See http://virtualplaying.com/interactive-frequency-chart/ to look for Hz ranges of instruments :) The xover should (??) also protect the HF from "too much" power. Note; with a DSP you can bypass the xover and set the HF much lower.

 

Haha; let me know when you try out the 904's :) (even without the HF). 

 

PS; for $180 each I'd get a second set if you have the room. And; welcome to the "904 club."

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19 minutes ago, Emile said:

Just rambling about a microphone and REW software. That's how many of us measure our speakers (and room).

 

So; just hook up a speaker to the HF output. You should be able to hear "only" about 900Hz and up. All the lower bass and some of the lower midrange should be gone. See http://virtualplaying.com/interactive-frequency-chart/ to look for Hz ranges of instruments :) The xover should (??) also protect the HF from "too much" power. Note; with a DSP you can bypass the xover and set the HF much lower.

 

Haha; let me know when you try out the 904's :) (even without the HF). 

 

PS; for $180 each I'd get a second set if you have the room. And; welcome to the "904 club."

I may try that, or may just wait for my K691 and 510.  How does the DSP work its magic, do I have to program something?

 

I was tempted to buy a second set (he wants to sell them all and it gets drastically cheaper the more you buy) or the 684 sub, but I was unaware just how large that thing is.  I unfortunate have no storage, and even one set with my La Scalas is pushing it while they are here. 

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1 minute ago, RandyH said:

-WOW ------the cabs are in great shape ,  you did really good at 180$ each

Thanks! All he has have very clean cabs, I grabbed the two I thought were best.  Very nice guy to deal with, actually ended up paying $160 each.  Offered me a third for $140 but I do not have enough room for it as a center nor did I think I’d find another single K691 and 510

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3 minutes ago, Amphicar said:

How does the DSP work its magic, do I have to program something?

The miniDSP's are very user friendly. You just hook it up to a PC and set the xover frequency as well as the slope. Pretty self explanatory :) But, try your xovers first ... never bothered with DSP on mine :)  

 

BTW, where are you located. Many people want 904's AND/OR a 684 sub, but "distance" usually presents a problem. Maybe you want to tell the seller about this forum so he can post them in the "Garage Sale" section :)

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Awesome! If I have the same as you I should be fine.  “Should”. I am located in Maryland, the seller is outside Philadelphia.  I told him, as have other members of this forum, but he is not interested in it.  He has had hundreds of responses to his Facebook ads, and like 10 people actually show up and buy.  I took photos of what he has left: 13 904s, a few parts cab 904s, a few parts cab 480 bass bins, and 1 684 sub.  

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  • 2 weeks later...

Next Question: For those of you who own(ed) 904’s, how do the horns attach?  I bought 510s but the 904’s did not come with any brackets, but does have two holes drilled in the top.  I will likely build boxes for them eventually, but in the meantime I’d like to rig something nice up. 

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Originals came with brackets. See below.

IMG_1310.JPG.61867f19689e9548436fa60a4cae2f0b.JPG

But ... pretty ugly ... just build a box :)  And in the meantime, just brace it with some books :) 

 

Had some ... gave them away to a forum member ... got them back as he didn't use them ... maybe I gave them away again ... not sure; will "look."

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2 hours ago, Emile said:

Originals came with brackets. See below.

IMG_1310.JPG.61867f19689e9548436fa60a4cae2f0b.JPG

But ... pretty ugly ... just build a box :)  And in the meantime, just brace it with some books :) 

 

Had some ... gave them away to a forum member ... got them back as he didn't use them ... maybe I gave them away again ... not sure; will "look."

Awesome, if nothing else I’d love some more pics of them.  What angle should they be at? Adjustable?  I work with a mechanical wizard who can build anything, so with a rough idea of what they should do & look like we can come up with something.  
 

Thanks! 
Tucker

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Good Morning!  I was able to get my 904’s assembled and fired up for the first time yesterday.  WOW! They are absolutely spectacular.  Still need to figure out how to wire in my L-pads to turn down the HF, it is a bit harsh.  Next step after L pads is to build boxes for the top, then get grilles.  I love these things!  They certainly take up a lot of space, though. 

63D3D94D-10B3-4FF3-B2B9-5AED25660412.jpeg

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28 minutes ago, Amphicar said:

They certainly take up a lot of space, though. 

 

You can get larger ones the next time... there's plenty of room.  How big is your TV?

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