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custom cross over idea / question non klipsch


HIFI4EVER

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I hope someone can help me here...

 

I used to have some  speaker lab k horns.  They rocked but  I sold them and got some vintage peavey sp3 speakers to learn on and play with.

 

Horns ended up being blown.  I replaced the diaphragms.

 

The woofer is not made for the box but works for me and very close in specs to me.

 

The right channel is now a little dull on the high end of things for treble, say snares etc.  I think the crossovers are about almost 40 years old.  I'd like to replace both sides right away.

 

Here is where it gets strange...  I hooked the woofers up directly to the amps until I got the horn parts and I loved the sound.  I got the horns back together and they sounded decent until I heard the issue or blew the cap on the right side horn.

 

I would really like to get more from the woofer.  It's not great for a sub in the box, but I like the sounds it can produce.  I'd like the crossover to be higher than the 800 so the woofer plays more mids/ highs since it reaches 2k?.  Maybe raise or keep the horns where they are.

 

Is this possible?

 

There are 2 caps, a transformer thing, and a coil on the crossover board.

 

 

 

box specs below.

https://assets.peavey.com/literature/manuals/80300649.pdf

 

woofer specs below

https://peavey.com/products/index.cfm/item/717/116641

 

 

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I've read enough on this board to understand us novices CAN NOT screw with XO's.  There are simply too many technical considerations we would not even think about.

 

Yeah you could probably change a value to change a XO point, but what about unintended consequences?  Can the woofer handle the higher XO point without beaming, or blowing up?  Does the HF now need to be changed as well?  Have you considered baffle step compensation in your changes?

 

If you want to update to newer caps due to the age of the old ones that would be fine, but my advice would be to use the current values.

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The enclosure some how doubles the ohms of the driver.  The stock woofer was 4 ohms and the horn loaded box made it 8.  this driver is 8 so now 16.

 

yes the 15" drivers were driven right from each of the 600RMS watt amps that power each and they sang just fine as full range drivers and cranked.

 

The bass is terrible for new kinds of music.  The bass is awesome for live stuff or classic rock which is what these mostly play.

 

I figure if the 15s handled full range mode fine they should be fine with a higher cap on them?  This gives a huge sound when they can ply full range.

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HIFI4EVER,

You have way too many unknowns to answer your questions somewhat accurately.

You said the woofers aren't made for the box.  Based on what you say the woofers are you can not expect significant bass as they appear to be more of a musical instrument woofer.  Only .9mm xmax and Fo of 50hz and response out to 2k (likely dropping like a rock at 1K -10db at 2k)

Said the woofers in the box double in impedance.  How did you measure them?

 

Since everything is an unknown, you would need to start from scratch and measure the woofer and horn's output and impedance in the box of the woofer and impedance of the horn and start all over.  Likely not the way to go but perhaps if you are not looking for deep bass and tried to move the crossover up to 1.2k-1.5k, you might be happy.  The original driver would work much better in that box though.

If you like the mids, keep your woofer for a midwoofer - put it in a smaller box, add a good woofer like Crites 1526 in that box (braced and ported appropriately), get your horn balanced and call it a day.  The crossover parts will not be cheap though.

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this is old pa stuff.

listing_pic_666955_1383329662.jpeg

 

 

Peavey forums told me the box doubles the ohms somehow.  Stock woofer was 4ohm scorpian, new woofer is 8ohm black widow.

 

If some one can set me up with what crossover to use that would be great since the woofer is like 16 ohms now and the horn is 8 ohms and I'd like the woofer to produce a little higher than the 800hz it cuts off at.  It's far more capable than that, and I don't want it to be so much a sub anymore either I like the higher frequencies it produces with out the cross over in place, but I still want to use the horns at around 1k -1.5k.

 

 

On the other hand since the horn is rated much lower power than the woofer can I make that 16 oms too and then they match, and also set the cross over a little higher.  Plus do I need an L pad for this?

 

thanks for the help ion this...

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6 hours ago, pzannucci said:

HIFI4EVER,

You have way too many unknowns to answer your questions somewhat accurately.

You said the woofers aren't made for the box.  Based on what you say the woofers are you can not expect significant bass as they appear to be more of a musical instrument woofer.  Only .9mm xmax and Fo of 50hz and response out to 2k (likely dropping like a rock at 1K -10db at 2k)

Said the woofers in the box double in impedance.  How did you measure them?

 

Since everything is an unknown, you would need to start from scratch and measure the woofer and horn's output and impedance in the box of the woofer and impedance of the horn and start all over.  Likely not the way to go but perhaps if you are not looking for deep bass and tried to move the crossover up to 1.2k-1.5k, you might be happy.  The original driver would work much better in that box though.

If you like the mids, keep your woofer for a midwoofer - put it in a smaller box, add a good woofer like Crites 1526 in that box (braced and ported appropriately), get your horn balanced and call it a day.  The crossover parts will not be cheap though.

Right, I'm not so concerned with earth shaking bass with these.  I want more of the lows and mids / highs out of this woofer mixed with highs of the horn.  Most people don't like the sound of these for home speakers, but I kind of like it and am trying to make the best out of them to suit my wants.

 

So if the woofer is 8 ohm and the horn is 8 ohm that is fine, but what if the woofer is now 16 ohms?

 

The stock one is 4ohm but cab makes it 8 I assume the crossover is set for that.   I should maybe change that as well as I'd like to up the cross over range on both drivers that are now crossed at 800hz.

 

The reason this started is that I have replaced both horn diaphragms and now one is sounding a little dull compared to how bright the other is on the highs, mids are a little muddy too on the dull one.

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The FH-1 is similar to the LaScala (SP-1 has an FH-1 bottom and CD horn on top in one cabinet). I don't know how the SP-3 cabinet would cause the 4 ohm woofer to appear as 8 ohms. That front loaded horn isn't going to load the horn much.

 

Bruce

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14 hours ago, Marvel said:

The FH-1 is similar to the LaScala (SP-1 has an FH-1 bottom and CD horn on top in one cabinet). I don't know how the SP-3 cabinet would cause the 4 ohm woofer to appear as 8 ohms. That front loaded horn isn't going to load the horn much.

 

Bruce

That's why you buy something like a woofer tester or make your own resistor network with a frequency generator.  It won't cause the 4ohm woofer to look like an 8ohn woofer in a cabinet that size.  Measure Measure Measure, and not with an ohm meter unless in conjunction with a resistor network.

 

A lot of folks buy the pre-made crossovers without much regard to the drivers being off 50% or more.  Maybe deviations like that in response aren't as bad as we believe but it sure will help a high frequency driver have a short life.

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So maybe it's the cross over making the woofer 8ohms?  

Displaying IMG_20170225_115921_430.jpg

 

Can someone please tell me if a store bought cross over will work in place of these parts?  I'd really like to just put something in and listen to them at this point.  If you can post some pre made that would help.

 

This is for home stereo listening.  Stock was 800hz 12db  I'f like to raise it to 1200hz

I was thinking about these kinds on ebay that are prebuilt, but if if I should just get different caps on mine let me know.  Also I don't know which ones to put in to change the frequency. 

 

I also want to eliminate the 1/4" jacks and do posts.

 

 

 

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On 2/24/2017 at 5:22 PM, HIFI4EVER said:

I guess what I'm saying is can I raise the horn to 1k and the woofer to 1.5+k ?

 

The horns are here

https://assets.peavey.com/literature/manuals/80302103.pdf

 

this will create overlap in one of the worst places possible. the 1khz zone. you can experiment but it can also get costly. if you're using a simple 6db/oct slope and you inspect your coil to see what value it is you can play around a bit until you find the sound your after.  a 1.25mh coil would give you roughly 1000hz on an 8ohm driver. you can use the calculator here for text book designs. you may experiment with crossing the woofer at 1000 and the mid horn at 1100-1200-1300 etc until you find your sound. 

 

https://www.diyaudioandvideo.com/Calculator/SpeakerCrossover/

 

http://meniscusaudio.com/ is my favorite place to buy crossover parts, parts express is also another but they won't ship small parts first class like meniscus will 

 

crossover slopes also sound different so simple 6db slopes not only are cheap, they can sound softer and less precise than 12-18-24db oct which as the name implies means you're down that many db in one octave of sound. they are also more simple and less expensive to create. the only place 6db slopes can get dicey is on tweeters. if you have a tweeter with an FS of 1000hz that likes to be crossed at say 2500hz and you use a 6db slope it's going to be 6db down at 1250hz but that's still some wattage at a frequency it can not take much power at. steeper slopes can really insulate it as well as cut off trouble ranges in certain drivers. 

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Awesome info.  I am playing with them now and some youtube sound tests with no horns just woofers.  they are plenty capable of highs, but at like 9k sometimes i heard them struggle a little and then settled down again after that and after 14k nothing to be heard..  I think since these are horns I might actually try some really high cross over point for the woofer to do the lows and mids. and the 22xt horn to do the high mids and highs.

 

I get the not mixing ranges in drivers now too.  I know it's probably wrong and out side the box but I really want to try moving the crossover way up on these now.  Really a neat sound to me.

 

 

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Can someone now please break down the parts int eh photo of my crossover above?  I think the stone piece is a resistor but what is the transformer piece?

 

Do those go bad?  I'm wondering if I can just solder some different value caps in the boards?

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I've decided to try 2000k cross over at the 12db 8ohms.

 

Can someone please post up the proper capacitors for me so I can order them?  I need a set for both speakers and all 4 need to be 8 ohms and 12db.

 

Thank you,

 

This is what I found...

 

1st Order Butterworth

2000 Hertz

8 Ohm Tweeter / 8 Ohm Woofer

Parts List
Capacitors
C1 = 9.94 uF
Inductors
L1 = 0.64 mH

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On 2/24/2017 at 8:22 PM, HIFI4EVER said:

I guess what I'm saying is can I raise the horn to 1k and the woofer to 1.5+k ?

 

The horns are here

https://assets.peavey.com/literature/manuals/80302103.pdf

 

No/Yes.  You need to cross the tweeter in at the top frequency of the woofer.  An overlap will cause an ugly peak in the response.  However, the woofer may well go up to 1500 Hz in that horn.  The woofer it is supposed to have was a 15825B scorpion, not the 1505-8 Black Widow, so there is no telling what your response curve actually looks like now.  The FH-1s I built with 1504-4 BWs in them produced more distortion than fundamental below 100 Hz.  You should expect the same. 

 

You can download a sine wave generator for your phone or laptop.  Buy a sound meter and take the speaker outside on flat ground.  Run enough tones through the woofer without the crossover and the tweeter WITH the crossover to generate a response curve for both.  You will be able to pick the uppermost frequency for the woofer visually.  You should also be able to see if the woofer is a good match for the cabinet.  Measure with the sound meter close to the ground to avoid reflections.  If you buy a Radio Shack meter, you can find correction curves on the web. 

Buy this:

https://www.parts-express.com/x-over-3-pro-software-cd-rom--500-919

and start designing. 

 

For one of my projects:

The Altec/Peavey combination I created required a lot of creativity and hours of trial and error to come up with a crossover that made them work.  Seems like I had the woofer calculated at 800 Hz, 3rd order and the tweeter with a funky, modified 2nd order at 3k with a knee at 1k to get an 1000 Hz crossover point with a small 2-ish dB dip.  OTOH, using a sub crossed at 100 Hz, live female vocals indoors sound too sweet.  The outdoor half-space response is very close to thee red line in the graph. 

Peav-tec=Final.jpg

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On 2/25/2017 at 0:14 PM, HIFI4EVER said:

this is old pa stuff.

 

 

 

Peavey forums told me the box doubles the ohms somehow.  Stock woofer was 4ohm scorpian, new woofer is 8ohm black widow.

 

If some one can set me up with what crossover to use that would be great since the woofer is like 16 ohms now and the horn is 8 ohms and I'd like the woofer to produce a little higher than the 800hz it cuts off at.  .......................................

 

If that short horn in fact doubles the impedance, you no longer have a 800 Hz low-pass, but closer to 400 Hz, if the crossover wasn't modified to match the woofer.  You need to measure and then start changing. 

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I guess it's the cross over that is set for a 4 ohm woofer.

 

yes I need a cross over with 8ohms, 2way, 2,000hz, and attenuater built in. 

 

 

I see what you mean though, maybe I should try 800 first, it just sounds way too low right now, unless I run the woofer full range.

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