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 24th March 2020, 11:51 AM   #71
Mygyth is offline Mygyth
diyAudio Member
 
Join Date: Mar 2020
Not sure if it was clear, but im planning to build a speaker box and put that in the bakerlite shell. Im aware that thin plastic would be a terrible choice for a speaker box. And yeah, im already planning to line the inside of the bakerlite with something to give it some strength (bakerlite is notoriously brittle especially once old). So i can just as easilly choose something to pad the gaps with and reduce any rattle. Maybe some sort of polyfill or a good quality bit of foam. To be honest, its not meant to be the worlds most amazing set of speakers. Its meant to be a stylish and nice sounding device to let me listen to music while i do some other projects. Its also a way for me to dip my toes into electronics and learn some stuff. Otherwise id just buy a bluetooth speaker. God knows it would have been cheaper rofl.

What is the advantage of going a ported speaker over a sealed or even passive radiator setup? As i understand it, it offers more bass, but in return, it ends up being alot bigger yes? So If my biggest concern is the size, why wouldnt i pick a slightly bigger driver with better low and mid range that will fit in a sealed or passive radiator enclosure of the size I want? Price is not a huge issue for me. The reason i picked cheaper drivers is because all small drivers are cheap as far as i can tell.
  Reply With Quote
Old 24th March 2020, 04:30 PM   #72
jReave is offline jReave  Canada
diyAudio Member
 
Join Date: Oct 2012
Ported gets a lower F3 than a sealed box but needs more internal volume. A passive radiator is essentially the same as a ported box, it's just using a resonant membrane instead of a port to get the same extra LF output. Passive radiators can be a good choice when the particular driver you are working with needs an excessively long port, which is often the case with smaller drivers that are designed to go low in small vented boxes like the Dayton ND91's for example. But the passive radiator usually needs to be slightly larger than the driver it's used with, so in your case, you would be running into problems with where to fit it in your proposed design - possibly on the sides in which case you would need to cut holes into the sides of the radio shell.

For this project, I would set minimum design goals of F3 = 80Hz, max SPL of about 90dB at 1m for musical content above 40Hz (that's a minimum for the max SPL - yes I know it may sound confusing) and drivers (and port opening?) that are going to fit within a 140mm (ht) x 150mm (wdth) baffle (or can you go wider than that? I'm still not sure). I think your max internal volume is about 3L gross but I'm not 100% sure about that either.

Going back a few pages now, I think the Dayton TCP115 and a smaller diameter tweeter can meet the above criteria. But there have also been some other suggestions made since then too that can work. I think it's kind of up to you which way you want to go now, so if you still can't decide, maybe try to figure out what it is you need to know that will help and ask those questions (if that's not perhaps stating the obvious?).

Should I also mention that if I'm trying to build an upper echelon speaker, I'm not confident to just rely on xo simulations? Real in-room and on-baffle measurements are required here. But for a very casual listening speaker, it doesn't need to be perfect and so in this case I am confident to say that we should be able to come up with a simulated xo without measurements that you can be happy with if you want to go that route.
  Reply With Quote
Old 24th March 2020, 07:41 PM   #73
Douglas Blake is offline Douglas Blake  Canada
diyAudio Member
 
Douglas Blake's Avatar
 
Join Date: Nov 2019
Location: Niagara Region Ontario
Quote:
Originally Posted by Mygyth View Post
Not sure if it was clear, but im planning to build a speaker box and put that in the bakerlite shell. Im aware that thin plastic would be a terrible choice for a speaker box. And yeah, im already planning to line the inside of the bakerlite with something to give it some strength (bakerlite is notoriously brittle especially once old). So i can just as easilly choose something to pad the gaps with and reduce any rattle. Maybe some sort of polyfill or a good quality bit of foam.
There is a product called No-Rez that comes in small sheets. It is sticky on one side and foam on the other. It's also a good inside liner in your speaker boxes. Alternatively small pads of cork will work almost as well.

Quote:
To be honest, its not meant to be the worlds most amazing set of speakers. Its meant to be a stylish and nice sounding device to let me listen to music while i do some other projects.
This is why I suggested the little 4 inch driver with the whizzer cone. It's super easy to work with... no crossover needed, and having heard them before I think the result will be just fine for you. Also that type of speaker was common in radios of that vintage, so it would not not be off-theme for your project.

The way these were usually used was with a pegboard back on the cabinet. That is as a semi-open-baffle design. They did it out of cheapness, but in your case it could be a very good idea since, again, it's easy to implement and it will sound ok.

As has been pointed out before, in a cabinet that small with stereo speakers you really can't expect a whole lot of hifi sound. But my memory of those old phillips and rca radios is that, given the era, they actually sounded pretty good.


Quote:
What is the advantage of going a ported speaker over a sealed or even passive radiator setup?
Lower bass extension... about half an octave is typical. You should read the other messages were we talked about that. I'm betting that if you get the bass in that radio down to 100hz you're going to be perfectly happy with the sound of it... many (dare I say "most"?) recordings have very little if any content under 80hz anyway.
  Reply With Quote
Old 25th March 2020, 08:31 PM   #74
Mygyth is offline Mygyth
diyAudio Member
 
Join Date: Mar 2020
Thanks for the info guys. For the record, the 150mm thing is because the bluetooth/radio/AUX decoder i bought for the system is 80mm wide. So 150mm gives enough room for me to have that at the front in the middle, and a speaker either side of it. Additionally, I figure that would leave enough room between the boxes for any other electrical components i need such as an amp or a crossover (If one ends up being used). Also, 150mm is the external width, including the materials used to make the spoeaker box.

The problem with a port is that the radio is only about 160-178mm deep. So unless I want the speakers hanging out the back, thats how far back the speakers can go. Like I said, i could probably compromise and see them coming out the back a couple of cm if i needed to, but a 22cm port would really start to impact on the aesthetic of the piece. So if its possible to fit a passive radiator at the back instead, then we can keep the speaker box a bit smaller and it doesnt need to poke out the back of the radio shell. At 150mm wide, I should be able to fit a 5inch passive radiator at the back of the enclosure no problem yes? Does that sound feasible? If not, then i probably have no choice but to ditch the 4 inch drivewrs which at least narrows my options.
  Reply With Quote
Old 26th March 2020, 01:09 AM   #75
AllenB is offline AllenB  Australia
diyAudio Moderator
 
AllenB's Avatar
 
Join Date: Oct 2008
First project - Will this crossover design work?
There are some very good 3" full range drivers available. If you can accept a separate woofer enclosure you could have higher volume levels and more bass.
  Reply With Quote
Old 26th March 2020, 05:32 PM   #76
jReave is offline jReave  Canada
diyAudio Member
 
Join Date: Oct 2012
I would recommend putting the unit up against a wall. This will have less baffle step loss which means it will play a little louder which means you need slightly less amp power all other things being equal.

In this situation, it's best for the ports or passive radiators to be in the front or side. For the passive radiators, that doesn't really work for your design. For the ports, it's not a problem on the front as you can easily just put a bend in a port to have it fit within the dimensions you've outlined as long as there is actually enough room for them on the front baffles.

Not exactly ideal, but if you do keep the unit a few inches out from the wall, rear ports or passive radiators will work more or less. So up to you on that one.

I understand your thinking a little better from your last post and drew up a quick sketch to see if the the TCP115 and a tweeter and ports will fit and indeed they do. (Pics 1 and 2 - top, bottom and back left off for visibility) Front baffle space is limited so I shrunk the port diameter to 2cm and used 2 of them. Port length is 18cm for each. Wood thickness is 12cm which I think would be fine in this application.

However, there is actually a fair amount of wasted interior space in the design. You don't actually need to house the amp etc in a separate exterior space. Instead I would suggest simply using 1 interior box, spit down the middle for the left and right channels. (Pics 3 and 4) Make it as big as you possibly can in the space you are working with. Seal the Bluetooth controller off if you have to and just include the rest of the electronics in either chamber.

My rough calculations suggest you might be able to get about 10 or 11L out of it and be able to fit just a slightly bigger diameter woofer on the baffle, up to about 130mm or so. And that opens up the possibility of several other drivers that can work for you that can probably play both louder and lower. Maybe better quality too.

Digest that. If that last idea works for you, maybe try to figure out a more precise estimate of the max internal volume you will have for each driver and then we can possibly make further driver recommendations for you.
Attached Images
File Type: jpg new radio layout 1.jpg (173.5 KB, 17 views)
File Type: jpg new radio layout 2.jpg (242.7 KB, 16 views)
File Type: jpg new radio layout 3.jpg (224.3 KB, 15 views)
File Type: jpg new radio layout 4.jpg (206.2 KB, 15 views)
  Reply With Quote
Old 26th March 2020, 05:48 PM   #77
jReave is offline jReave  Canada
diyAudio Member
 
Join Date: Oct 2012
Forgot to mention - tweeter with the TCP115 is the Vifa XT25SC40 without the faceplate.
  Reply With Quote
Old 27th March 2020, 08:35 PM   #78
Mygyth is offline Mygyth
diyAudio Member
 
Join Date: Mar 2020
@JReave Oh lol, I did not know the ports could be bent. That opens a heap of options. I really like the design you have there. Ill have to make a couple of minor adjustments just because the radio shell has some wierd ridges and stuff to work around that dont show up well in photos. But yeah, totally workable.Thankyou so much. I really appreciate all the help you have given me on this design. I do have some questions.
Are the two woofers in that design different sizes (image 3, your last reply), or are you just showing the possibilities?
Is 130mm the overall outside diameter i can have or the baffle cutout diameter?
In image 2 of your last post, the two inner walls are different. What is the purpose of this? Were you imagining the electronics going in that area? Do those walls fully partion the space?
Thanks again.

@AllenB, @Waxx, @Douglas Blake, @Pharos, @anyoneimissed I really appreciate all your comments. This is a really big learning process for me. Thankyou for your continued patience. I am going back constantly to review everyones feedback to try to work this out. Your input is all really appreciated.
  Reply With Quote
Old 28th March 2020, 02:45 PM   #79
jReave is offline jReave  Canada
diyAudio Member
 
Join Date: Oct 2012
Image 3 is just showing the possibilities. Driver sizes are different left and right - 115mm left and 130mm right I think for the out side diameters. The left one I was just lazy on and the cutout is the whole diameter of the the driver flange. The right one is more realistic for what you have to do.

Inner wall difference in pic 2 was because the driver was so close to the cabinet wall, so if that worried you I was just trying to show the possibility of something you could do to fix that. Not so important any more as it looks like that design is now toast.

Ports don't actually need to be round either. You can use any shape that has the same cross-sectional area. Something called a slot port might be a good idea for you because it saves just a tiny little bit of internal volume because it uses the existing cabinet walls as one of the port sides. Put it on each side of the center wall I would think. See below.
Attached Images
File Type: jpg ports.jpg (64.9 KB, 8 views)
File Type: jpg ports2.jpg (89.6 KB, 3 views)
  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 622 Yesterday 12:13 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 11:50 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