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

Portable Bluetooth Speaker Build With Passive Radiators Build
Portable Bluetooth Speaker Build With Passive Radiators Build
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 11th July 2018, 12:53 AM   #1
PedroDeMio is offline PedroDeMio  Brazil
diyAudio Member
 
Join Date: Apr 2012
Default Portable Bluetooth Speaker Build With Passive Radiators Build

Hello everyone

I've been here a long time but more on the reader side, today a decided to share the new portable speaker I've been working.

First, this probably the 5th portable speaker I've built, so its a culmination of everything I've learned on previous build plus a few bookshelf and sub-woofers.

The drivers will be the same as my previous box, two 4,5" Eastech mid bass and two Peerless DQ25SC16. No wait, 4 of each, since I will build two almost identical boxes, one for me and one for my father.

This is what I wanted:
-Smaller than the previous one (10l max vs 21l)
-Play way lower

This mid bass was something golden that I found on a electronic stores, bought it what parameters whatsoever. After measuring I knew it would perform well

Bellow is an simulation in Hornresp of what I came up. Extension to almost 40 Hz in a 3,5 l enclosure. The way to do that was tunning the passive radiator really low as a mean to keep excursion under control, and them just brute force trough equalization.

Response @ 2pi
Click the image to open in full size.

Click the image to open in full size.

In theory it would work, but I wasn't so sure, so I build a test box to measure and more important, listen. My biggest worry is that the high excursion even at low volumes would distort the rest of the spectrum

Click the image to open in full size.


It worked perfectly, I used my Mini DSP to apply the required equalization and took a quick measurement to see what the response looked like, and after that hooked up a tweeter just to listen for a few hours and see if the sound was pleasing.

Near field response of each driver and summed response

Click the image to open in full size.

After that what was left to do was finish the box design and design a filter to go with it

For the box I went with the smallest size that could fit the drivers, the final dimensions is 401x148x183mm, all made to be CNC cut

Click the image to open in full size.

Click the image to open in full size.

Click the image to open in full size.

For the filter I have a PEQ, a 4th order butterworth low pass and a BSC, all adjustable from outside the box by just removing the back portion of the cloth. The PCB should arrive soon

Click the image to open in full size.

Click the image to open in full size.


Today I received all CNC cut wood, my plan is to assemble the box this week and take some measurements to start working on the crossover

Click the image to open in full size.
  Reply With Quote
Old 11th July 2018, 05:53 AM   #2
Jonhny is offline Jonhny  Sweden
diyAudio Member
 
Join Date: Mar 2005
Location: Sweden
Very impressive build!
Do you have any information about the midbasses? Part number and so on?
I assume you know from experience what is required from your filter PCB if you dare to order it before measuring the box

What kind of amp are you going to use?
  Reply With Quote
Old 11th July 2018, 02:26 PM   #3
PedroDeMio is offline PedroDeMio  Brazil
diyAudio Member
 
Join Date: Apr 2012
Thanks

The part number is FSB527550-5B24. Unfortunately the 8 ohms versions is long gone and the 12 ohms was available until recently but I went to check and it's also gone. I bought them 5 years ago

About the filter, after I modeled the required filter and tested on the test box with the MiniDSP I am pretty confident that it will work, bellow is the expected filter response. Red with just the PEQ, blue PEQ + High pass and purple PEQ + High Pass + BSC

Click the image to open in full size.
  Reply With Quote
Old 11th July 2018, 06:07 PM   #4
Jonhny is offline Jonhny  Sweden
diyAudio Member
 
Join Date: Mar 2005
Location: Sweden
That bass is going to dig deep! Keep us updated!
  Reply With Quote
Old 11th July 2018, 08:51 PM   #5
PedroDeMio is offline PedroDeMio  Brazil
diyAudio Member
 
Join Date: Apr 2012
Hopefully it will, the drawback is that the overall level is reduced a lot in order to keep under the excursion limits, but I don't need it to be super loud. The previous version used 4 of these drivers, but I can count on one hand how many times I used them to the full potential
  Reply With Quote
Old 12th July 2018, 08:32 PM   #6
PedroDeMio is offline PedroDeMio  Brazil
diyAudio Member
 
Join Date: Apr 2012
Today I printed and started assembling the passive radiators, still need two order 4 more surrounds for the other box since the initial plan was only one PR per chamber

Click the image to open in full size.

Also put the first speaker together and put on some threaded inserts for mounting the drivers

Click the image to open in full size.

Click the image to open in full size.

Last edited by PedroDeMio; 12th July 2018 at 08:56 PM.
  Reply With Quote
Old 28th July 2018, 12:20 AM   #7
PedroDeMio is offline PedroDeMio  Brazil
diyAudio Member
 
Join Date: Apr 2012
A few updates:

Tested the acoustic cloth and how to attach it using a notch on the back, I didn't like the looks and will use a plain black cloth, unfortunately it was not cheap

Click the image to open in full size.


Today was measurement day, in the pic the speaker on the jig I made to accurately set the angles

Click the image to open in full size.


The grill is causing some serious problems with the tweeter response, I will raise it from the baffle so it become flush with the grill, but them the woofer whole can also cause some problems

Also my impedance measurement jig is somehow measuring about half of the actual impedance, I don't know if I can trust the data by just doubling it

Click the image to open in full size.
  Reply With Quote
Old 31st July 2018, 12:14 AM   #8
PedroDeMio is offline PedroDeMio  Brazil
diyAudio Member
 
Join Date: Apr 2012
After another round of measurements I have a crossover, i may tweak it a bit

I'm not sure about the Dz of the tweeter, following Troels methodology (Time-Alignment) I arrived at 33mm and adjusted the crossover accordingly, but them I can't get a deep notch at the response anymore, I guess that's the price for not having the drivers acoustically aligned

Any sugestions?

Normal

Click the image to open in full size.

Out of phase

Click the image to open in full size.
  Reply With Quote
Old 31st July 2018, 06:03 AM   #9
Mario Pankov is offline Mario Pankov  Europe
diyAudio Member
 
Join Date: Aug 2007
Location: Sofia
Portable Bluetooth Speaker Build With Passive Radiators Build
Subscribed.

I am onto this as well, see if you can source Monacor SP-60 - these have very low Fs, suitable for sealed and 90db/w (and are cheap ). They require a large box, so small sealed with active help should work. Just an idea.

Why would you go for passive crossovers and not active ones (smaller, cheaper, can boost bass output, lighter)? Something like a TPA3255 I believe can do the job and run quite long on batteries?
  Reply With Quote
Old 31st July 2018, 05:30 PM   #10
PedroDeMio is offline PedroDeMio  Brazil
diyAudio Member
 
Join Date: Apr 2012
Just looked into it, they look nice, a bit pricey though

At this point I kinda wished that I went full active, the PCB would be a bit more complex but nothing I can't manage. The amp for the tweeter can be cheap, 10W would be more than enough since it's way more sensitive

I will simulated an active crossover and see what it looks like

Also the PCB's arrived a few days ago, they look beautiful and very high quality, for the price it's a steal

Click the image to open in full size.
  Reply With Quote

Reply


Portable Bluetooth Speaker Build With Passive Radiators BuildHide 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
Bluetooth speaker build... more bass!!! Hayden Multi-Way 4 26th July 2018 07:32 PM
First Bluetooth Speaker Build Tips bellamym Class D 6 17th September 2017 12:42 PM
"Portable" bluetooth speaker build advice Sonicfury405 Multi-Way 17 16th March 2017 08:26 AM
Bluetooth Speaker (Build Log) MatthewP Everything Else 0 4th November 2013 08:39 AM
Passive Radiators (where at buy/how to build) Puggie Multi-Way 1 10th November 2004 03:22 PM


New To Site? Need Help?

All times are GMT. The time now is 08:31 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.00%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio
Wiki