young audiophile building JBL L300

Hi everyone i am 16 and a new Audiophile i had a neighbor Dale that built huge horn speakers he had dozens and dozens of speakers mostly old JBL ,Altec Lansing , Stephens true sonic ,Electro voice but he had some new stuff also. Some of his speakers where so loud i could feel a acoustic guitar play they were amazing. He was going to build me some speakers cause i would help him work around his house all the time and i did not know he was doing it. But he died in March and never had the chance to built them. Then His son came to town get all his stuff and while helping him and his mom she remembered Dale had these speakers in the corner for me so she gave them to me. They are JBL L300 cabinets no grills Altec Lansing 803 woofers BMS 4550 mid range and Beyma cp21 tweeters but no crossover. I found the crossover for the JBL L300 back in April on ebay but they sold for $685 i can't afford that my dad said if i buy the parts his friend will solder them for me and wire the speakers up. So my question is can i use the JBL L300 crossover without the JBL speakers? Will it still sound good or will i have to use some other crossovers? Can i design some with a online crossover calculator? And his son also gave me his old receiver he had when he lived at home it is a Sansui 80/80 it.s 80 watts per channel will this be a good match with my speakers? Reading online it says 150 watts is best to power L300's. Hope to hear some good advice i can't wait to hear my speakers. One day when i have more money i will restore these to stock i see they sell for like $5000.00 thats crazy their almost 3 times older than me.
 
Hi, by doing a quick "search" on JBL L300 it comes out a PDF by N. Pass
Of course he refers to the same exact drivers used in the original, but you can read it and take inspiration.
The 1st order HP ( high-pass) for the tweeter seems rather unadeguate for high listening levels but will suffice for normal listening- a compression driver is well over 105 dB/ W / m and the L-Pad brings down many deciBels
 

eriksquires

Member
2013-05-10 4:11 pm
Online calculators stink. I would suggest you invest in learning how to roll your own crossover. you will neew room eq wizard and a good microphome, the Dayton imm 6 for $12 will do. and a mic stand. then feed the data you collect into Xsim.

Then you can really get started and many here will help you.
 

ticknpop

Member
Paid Member
2005-05-28 9:43 pm
toronto
The cabinets may be L300s , but the drivers remining with them have nothing to do with L300s so the L300 crossover is useless with the drivers you have. Old JBL drivers go for a lot of money these days. (I know we have 8 x 2245, 4 x 2402, 4 x 2441, 4 x 2395 lens, and 4 x 2405 tweeters in our shop PA system ).
Our version of 4 x 4350 monitors with twin 18s insead of 15s

For the short term You can come up with a simple crossover for what drivers you have, but I would really recommend you restore them with original drivers and Nelson's crossover, it will take you years to save for them and hunt them down on Ebay or Jamming Jersey but it will be worth it. There is a reason these are so sought after,
 

eriksquires

Member
2013-05-10 4:11 pm
Ticknpop kind of raises a good point. How much do you want to learn about speaker building, and how much do you want to listen to them finished?

I mean, this sounds like a very fun/cool project, but could also get expensive and last a long time. :)

We're happy to help with learning about speaker and crossover design, but make sure the project is a meal you can finish. You may be better off selling what you have, and getting something smaller that works now.

Best,

Erik
 
Instead of designing/investing in passive crossover for existing cabinet with 'other' drivers. Why not get a mini dsp, analyzer mic and REW. It will not cost a arm and a leg and you can fiddle with parameters all day long without touching a soldering iron.

Pass the measurements here and maybe we can help to make it work with the drivers you have.
 
Instead of designing/investing in passive crossover for existing cabinet with 'other' drivers. Why not get a mini dsp, analyzer mic and REW. It will not cost a arm and a leg and you can fiddle with parameters all day long without touching a soldering iron.

Pass the measurements here and maybe we can help to make it work with the drivers you have.

I was up late reading about crossovers and i am even more confused. I am still saving money to get my first car so i would like to spend around $200.00 max for now so i can at least listen to them. Then in the future i will buy all the right components off ebay to restore them to original. And i am really just getting into this so i know absolutely nothing. Is a 4th order crossover good? seems from what i have read they are they are in phase & time aligned would that work for my speakers? Found a 3 way crossover calculator it would not let me use the 800hz to 8500hz frequency range but it did do 800hz to 8000hz and i made a list of the components and priced them at parts express and i can afford them is this a good choice?
 
Online calculators stink. I would suggest you invest in learning how to roll your own crossover. you will neew room eq wizard and a good microphome, the Dayton imm 6 for $12 will do. and a mic stand. then feed the data you collect into Xsim.

Then you can really get started and many here will help you.

I am afraid all that is over my head right now i just need to learn the basics about speakers before i can do stuff like that.
 
Right now i just want to get them going i have been doing some reading and it seems like all the components i have are good especially the BMS 4550. And i was also reading about crossovers seems like a 4th order is good and my speakers would be time aligned and in phase right? After i Graduate and get my car i will start working and then i will buy all the original components i figure it will be about $2500.00 witch will be fine with me considering they sell for $5000.00 it will be a good investment. I want more than anything to hear these bad boys. After hearing my neighbors system play Pink Floyd and Deep Purple i was hooked. And i really want to keep these speakers they are sentimental they belonged to someone that turned me on to classic rock and playing guitar two things i love so i will never part with these ever.
 
The BMS 4550 goes up to 20k. You don't really need the Beyma.

A 2way xover is a LOT easier to do than a 3way.



Eventually and very much depending on your woodworking skills you could build an Altec VOTT A7, the natural home of your 803s.
Whiich btw appear to be worth about $400ea on the s/h market.


PS: As far as I know the 803 woofer was renamed 416 in the mid '60s to avoid confusion with Altec's 800 series of compression drivers and horns.
 

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A simple 2nd order Linkwitz Riley Xover will get you up & running;
1st problem- to find the actual impedance of the drivers at the crossover frequency –
Can’t find any Altec 803 impedance plots so let’s assume it’s 16 ohms
At 800Hz the BMS looks to be about 10 ohms (from the manufacturer’s spec sheet)
Plugging these values into an online calculator ERSE - Crossover Calculator - Second Order 2 Way
we get
For the woofer inductor, 6.4 mH, woofer Cap 6.2uF
For the BMS inductor, 4mh, BMS Cap, 10uF
(Use bi-polar electrolytic caps & Ferrite core inductors)
There is 14dB difference in their outputs so an L Pad is needed on the tweeter,
Probably easiest to buy adjustable ones, something like this:
Parts Express Speaker L-Pad Attenuator 50W Mono 1" Shaft 8 Ohm
The above will be far from Ideal but will get you listening to music without breaking the bank
 

AllenB

Moderator
Paid Member
2008-10-18 11:31 am
seems like a 4th order is good and my speakers would be time aligned and in phase right?
The mid is further back than the tweeter so probably not. You could learn a lot about how JBL dealt with this by looking at the original crossover. Although it will not be spot on if you are using different drivers it will be a good place to start, and you can expect to to make other adjustments from there. If you are not planning to measure this might be the way to go, at least for some of the crossover.

I would try to find some info on the differences with the drivers from the originals.
 
The BMS 4550 goes up to 20k. You don't really need the Beyma.

A 2way xover is a LOT easier to do than a 3way.



Eventually and very much depending on your woodworking skills you could build an Altec VOTT A7, the natural home of your 803s.
Whiich btw appear to be worth about $400ea on the s/h market.


PS: As far as I know the 803 woofer was renamed 416 in the mid '60s to avoid confusion with Altec's 800 series of compression drivers and horns.

Thanks for the info after reading your post i started doing some searching about Altec and run across the econowave and the Z19 crossover and i have the 803/416 and the BMS 4550 so i have decided to go in that direction. I will be keeping the L300 cabinets and little by little i will buy the components to restore them. My uncle is going to sell the beyma cp21 on ebay for me so that money will go toward buying crossover components and building cabinets.
 
Online calculators stink. I would suggest you invest in learning how to roll your own crossover. you will neew room eq wizard and a good microphome, the Dayton imm 6 for $12 will do. and a mic stand. then feed the data you collect into Xsim.

Then you can really get started and many here will help you.

It sounds difficult could you tell me more? Whats a good place to start reading about how to design my own crossovers. After reading a reply from forum member Charles Darwin i have learned about the econowave and the Z19 crossover so thats what i am going to build. I will restore the JBL L300's when i am working and can afford to until then i would still like to read and learn more about the equipment used by DIY builders.
 
A simple 2nd order Linkwitz Riley Xover will get you up & running;
1st problem- to find the actual impedance of the drivers at the crossover frequency –
Can’t find any Altec 803 impedance plots so let’s assume it’s 16 ohms
At 800Hz the BMS looks to be about 10 ohms (from the manufacturer’s spec sheet)
Plugging these values into an online calculator ERSE - Crossover Calculator - Second Order 2 Way
we get
For the woofer inductor, 6.4 mH, woofer Cap 6.2uF
For the BMS inductor, 4mh, BMS Cap, 10uF
(Use bi-polar electrolytic caps & Ferrite core inductors)
There is 14dB difference in their outputs so an L Pad is needed on the tweeter,
Probably easiest to buy adjustable ones, something like this:
Parts Express Speaker L-Pad Attenuator 50W Mono 1" Shaft 8 Ohm
The above will be far from Ideal but will get you listening to music without breaking the bank

What is impedance? When i used the online calculator i thought i was doing it right by entering the ohm of the speakers witch is 8 ohm. How can i measure impedance? I have a solution for my crossover but i still want to learn about how to design my own.
 
Thanks for the info after reading your post i started doing some searching about Altec and run across the econowave and the Z19 crossover and i have the 803/416 and the BMS 4550 so i have decided to go in that direction. I will be keeping the L300 cabinets and little by little i will buy the components to restore them. My uncle is going to sell the beyma cp21 on ebay for me so that money will go toward buying crossover components and building cabinets.

Sounds like a plan!

Hard to go wrong with an Econowave but just to add something else if you scroll down in the linky there is another link to the plans of an Onken enclosure for Altec 803/416.
Not sure what the advantages of an Onken really are because I've never owned a suitable woofer but those who have heard them tend to swear by Onkens.
Since it only changes he bass loading I suppose there should be no changes needed in that crossover you've found. I'm an active guy myself and know little enough about passives to be quite dangerous.

Here is the linky: Inner Magazine - My Altec Valencia Iconics