Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Multi-Way Conventional loudspeakers with crossovers

First project - Will this crossover design work?
First project - Will this crossover design work?
Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 15th March 2020, 04:13 AM   #1
Mygyth is offline Mygyth
diyAudio Member
 
Join Date: Mar 2020
Smile First project - Will this crossover design work?

Hi everyone, this is my first post, and my first project. Please be patient with my newb questions.

First up, sorry if this is posted in the wrong forum, please let me know where to post it if so.

So i have no experience at all in speaker design or building, and only middling experience in electronics. However, ive been interested in taking on a project for a long time and have been watching youtube vids/collecting gear like soldering iron etc for about a year now.

A few weeks back, i found a retro style radio for sale at a garage sale. I decided to make this my first project. This is intended to be a bluetooth speaker system for my workshed. I want it to have bluetooth radio and AUX functionality with a remote control. So I stripped out the old electronics, and cleaned up the shell. (cleaner than whats shown in this pic anyway)

Click the image to open in full size.

I bought a bluetooth decoder with FM, Aux and USB functionality on ebay.

Click the image to open in full size.

I then went to do the quick job of making some speakers for it.... Oh bless past my innocence.... 3 weeks later, countless hours on youtube, a few tutorials and 3 programs later, i have this:

Click the image to open in full size.

Now, like i said, i have zero experience, and am just learning what i can on the fly. But, i think if ive understood everything correctly, what i have here should work? I figured id hop on here and ask you guys what your opinion was before i fork out several hundred dollars on making it happen.

FYI, this is the tweeter i plan on using:
ND28F-6 1-1/8" Neodymium Dome Tweeter 6 Ohm - Dayton Audio

And here is the woofer im looking at:
TCP115-4 4" Poly Cone Midbass Woofer 4 Ohm

Im planning to make 2 closed speaker boxes out of MDF, (one woofer and one tweeter in each). one for each side of the radio case, and mount my bluetooth thingo in the middle. Put some nice cloth in front of the speakers to keep with the retro asthetic. etc etc.

My biggest question right now is the 2400uF capacitor on the woofer. I am given to understand that ususally, you want to stick with film capacitors in stereo design. However, obviously a film capacitor of that size would be prohibitivly expensive. This video seems to claim that if you have a large electrolitic capacitor in series with a resistor, and those in parralel with a film capacitor, then it should be fine.

YouTube

Now im pretty sure that describes what i have in the above schematic. Can anyone confirm for me please if the above system will work with an electrolytic capacitor in the 2400uF position. If not, what are my alternatives?

Many thanks everyone
Attached Images
File Type: jpg radio shell.jpg (258.5 KB, 65 views)
File Type: jpg brains.jpg (91.3 KB, 76 views)
File Type: png cross over draft 5.PNG (406.9 KB, 140 views)
  Reply With Quote
Old 15th March 2020, 05:42 AM   #2
AllenB is offline AllenB  Australia
diyAudio Moderator
 
AllenB's Avatar
 
Join Date: Oct 2008
First project - Will this crossover design work?
Electrolytic capacitors get a bad rap, but they aren't as bad as that.

Anyway, remove it altogether. The 2400uF value means that it is acting like a piece of wire at audio frequencies.
  Reply With Quote
Old 15th March 2020, 06:08 AM   #3
Mygyth is offline Mygyth
diyAudio Member
 
Join Date: Mar 2020
Thanks AllenB. Tried that, and like you said, made no difference to the overall graph. I guess that was an easy fix

Does everything else look good to go?
  Reply With Quote
Old 15th March 2020, 06:18 AM   #4
Mygyth is offline Mygyth
diyAudio Member
 
Join Date: Mar 2020
Also, My next question is how do i choose a amplifier and power source for the proposed system?
  Reply With Quote
Old 15th March 2020, 06:41 AM   #5
AllenB is offline AllenB  Australia
diyAudio Moderator
 
AllenB's Avatar
 
Join Date: Oct 2008
First project - Will this crossover design work?
Quote:
Originally Posted by Mygyth View Post
Does everything else look good to go?
I would probably start by trying to ditch the remaining woofer resistor. This will take some adjustment of the other two components to restore the balance. This should take the impedance back above 2 ohms.
Quote:
Originally Posted by Mygyth View Post
how do i choose a amplifier and power source for the proposed system?
What are your Voltage and current requirements for each component?
  Reply With Quote
Old 15th March 2020, 11:05 AM   #6
Mygyth is offline Mygyth
diyAudio Member
 
Join Date: Mar 2020
Quote:
Originally Posted by AllenB View Post
I would probably start by trying to ditch the remaining woofer resistor. This will take some adjustment of the other two components to restore the balance. This should take the impedance back above 2 ohms.
Thanks again for your advice. I tried taking away the resistor, but it creates a HUGE spike in the impedence @ 53 Hz (Image 1). I couldnt seem to reduce that spike with the other components. So I tried adjusting the resistor's value and adjusting the other components until i had a minimum impedence of 4 Ohms (image 2). Im worried that the impedence graph is still too variable.
1. What is the minimum impedence i should be aiming for?
2. How much variability is acceptable in the impedence graph?
3. What other options do i have?

Quote:
Originally Posted by AllenB View Post
What are your Voltage and current requirements for each component?
Had to use a website to calculate the current and volts from the watts and impedance, but here we go

Tweeter:
Impedance: 6 Ohms
RMS: 30 watts
Current: 2.23606798 amps
Voltage: 13.4164079 V

Woofer:
Impedance: 4 Ohms
RMS: 40 watts
Current: 3.35410197 amps
Voltage: 13.4164079 V
Attached Images
File Type: png cross over draft 7 no resistor.PNG (422.8 KB, 129 views)
File Type: png cross over draft 7.PNG (416.3 KB, 57 views)
  Reply With Quote
Old 15th March 2020, 11:29 AM   #7
AllenB is offline AllenB  Australia
diyAudio Moderator
 
AllenB's Avatar
 
Join Date: Oct 2008
First project - Will this crossover design work?
Quote:
Originally Posted by Mygyth View Post
it creates a HUGE spike in the impedence @ 53 Hz
Why don't you like this?
Quote:
Had to use a website to calculate the current and volts from the watts and impedance, but here we go
I thought you wanted to power the bluetooth frontend?

Is there a reason you cannot use a normal audio amplifier or is that ok?
  Reply With Quote
Old 15th March 2020, 11:38 AM   #8
Mygyth is offline Mygyth
diyAudio Member
 
Join Date: Mar 2020
I was under the impression that the impedence graph should be as close to flat as possible?

The bluetooth device is 5V, not sure what current it uses. Ill get my altometer out tommorrow to check. Honestly, ive not really looked at different amplifiers at all yet. I figured id design the speakers first, and get an amp/power supply that suited it after i knew what i needed.
  Reply With Quote
Old 15th March 2020, 11:50 AM   #9
system7 is online now system7  United Kingdom
diyAudio Member
 
system7's Avatar
 
Join Date: Aug 2008
Location: Portsmouth UK
I think you should look at a vaguely similar well-executed project for an idea that might work:

Eekels' Mini

Basic circuit should work with most 4" plus 1" drivers. And it does everything that is good here. You always get an impedance peak on the bass, whether closed box or reflex.

FWIW, you have selected a Qts 0.35 woofer more suited to reflex, which means you have a port in the cabinet. About 5L, I'd guess based on a Vas of 3.1L.
__________________
Best Regards from Steve in Portsmouth, UK.

Last edited by system7; 15th March 2020 at 11:55 AM.
  Reply With Quote
Old 15th March 2020, 11:51 AM   #10
AllenB is offline AllenB  Australia
diyAudio Moderator
 
AllenB's Avatar
 
Join Date: Oct 2008
First project - Will this crossover design work?
Quote:
Originally Posted by Mygyth View Post
I was under the impression that the impedence graph should be as close to flat as possible?
To deal with this you can use a Voltage source amplifier. Typical audio amplifiers are like this. They are designed to ignore these impedance variations (sort of).
Quote:
The bluetooth device is 5V, not sure what current it uses.
Ok, if it already has a supply then we don't need to measure that one.
  Reply With Quote

Reply


First project - Will this crossover design work?Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Pulseaudio Crossover Rack - multi-way crossover design & implementation with linux Tfive PC Based 612 29th March 2020 10:15 PM
crossover design sb17nrx ,sb29rdnc. Will this work? mallikreddyk Multi-Way 40 27th October 2018 06:28 AM
3 Way Active Crossover Design project powagrip Multi-Way 13 23rd February 2005 08:06 PM
have a speaker design- need crossover- will this work? trespasser_guy Multi-Way 1 26th August 2002 05:23 AM


New To Site? Need Help?

All times are GMT. The time now is 10:31 AM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 14.29%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Copyright ©1999-2020 diyAudio
Wiki