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

I Hate Ported Speakers!!!
I Hate Ported Speakers!!!
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 29th April 2014, 05:38 AM   #51
fatmarley is offline fatmarley  England
diyAudio Member
 
Join Date: Aug 2003
Location: Cheltenham
Quote:
Originally Posted by Ron E View Post
Port resistance is never useful in a properly aligned vented box, it just reduces output.
Couldn't the same be said of a sealed speaker? - your getting less output because you don't have a port.
  Reply With Quote
Old 29th April 2014, 05:40 AM   #52
fatmarley is offline fatmarley  England
diyAudio Member
 
Join Date: Aug 2003
Location: Cheltenham
Quote:
Originally Posted by perempe20 View Post
we tried SPH-200KE (8" Monacor woofer) in a ported test box with a tweeter, and it handled Boogie Street easily in bass response.
I have a pair of those in the shed and was thinking of doing a 3-way with them and the Scanspeak.
  Reply With Quote
Old 29th April 2014, 08:04 AM   #53
marco_gea is offline marco_gea  Italy
diyAudio Member
 
Join Date: Apr 2005
Location: London, UK
Quote:
Originally Posted by fatmarley View Post
Ok, now that's got your attention I'd like a bit of advice. Ive just bought a pair of 18w 8542-00 from ebay. The foams were shot, so I replaced them and I'm now trying to think of what to do with them.

For a 2-way speaker these drivers would have to go in a ported box to get some bass out of them. As I said, I don't like ported speakers, so (a) I don't know anything about them (I didn't read that section of my Loudspeaker Design Cookbook) and (b) I don't like the sound of ported speakers.

Could someone who thinks that ported speakers can be made to sound as good as sealed, design me a ported box that will sound like a sealed. I know the roll-off rate will be different but what I mean is, I don't like that slow, boomy, one-note bass you often get from ported speakers. I want something clean and tight, if possible.

If possible I'd like to put the ports in the sides like the Royd Minstrel.

I Hate Ported Speakers!!!


EDIT:

I'd also like to make them a floorstander because I can't be bothered with stands.
Considering all bass-reflex speakers to produce "slow, boomy, one-note bass" is trite generalization. The problem with most such speakers is that they are designed to try and circumvent the laws of physics, which, you guessed it, does not work.

Getting good deep bass out of a small (mid)-woofer with any reasonable efficiency is just not going to happen. In an effort to squeeze some bass out of such undersized woofers, most designers opt to compromise on the "good" part of it - hence the "slow, boomy, one-note bass" that you mistakenly attribute to bass-reflex per se.

Try and listen to a medium-low EBP 15" woofer in a properly tuned (i.e. low Fb) bass-reflex box and you will be surprised how "fast, tight and musical" it sounds

To simplify, think of it this way: (1) small woofer; (2) deep bass; (3) high-quality (mid)bass. You can have two of those but NOT all three. There's no such thing as a free lunch.
Going back to your woofer of choice, you'll have to accept that there is a trade-off between quality and quantity of bass.

Marco
  Reply With Quote
Old 29th April 2014, 08:08 AM   #54
marco_gea is offline marco_gea  Italy
diyAudio Member
 
Join Date: Apr 2005
Location: London, UK
Quote:
Originally Posted by planet10 View Post
But, because of dynamic changes in T/S parameters, a vented box is mostly not properly aligned.

dave
True, but then again, that's much less of an issue with large, high-efficiency woofers (T/S parameters change because of excursion - which is minimized by large size - and thermal compression - which is minimized by high efficiency)

Again, there's no fooling the laws of physics - despite what the marketing department of most commercial hi-fi manufacturers would have you believe.

Marco
  Reply With Quote
Old 29th April 2014, 08:15 AM   #55
phase_accurate is offline phase_accurate
diyAudio Member
 
Join Date: May 2002
Location: Switzerland
Quote:
Couldn't the same be said of a sealed speaker? - your getting less output because you don't have a port.
This is definitley not the same: Port resistance is friction i.e. the generation of heat from mechanical energy. A closed box (unless leaky) is a reactive component so no heat should be generated mechanically in theory. There is of course some stuffing used in practice...

Since I take care about transient-behaviour I use closed-box a lot. But there are many ported speakers around that are definiltely fun to listen to.

I once built a box with a JBL 2206 PA woofer and a bi-radial horn (the type used in the 4430 monitor). The box was designed slightly larger than what box calculators suggest. And it was also tuned slightly lower than suggested. It had a premature rolloff that should be electronically compensated in theory in order to get flat response. I always listened without compensation and it sounded great, especially with loud music of all sorts because it never sounded strained.

In general:
If it must be small and loud there is not much choice except ported. But if you can go the extra mile and spend a little more on drivers and power then closed-box is definitly worth a try.


Regards

Charles
  Reply With Quote
Old 29th April 2014, 08:28 AM   #56
Scottmoose is offline Scottmoose  United Kingdom
diyAudio Member
 
Scottmoose's Avatar
 
Join Date: Mar 2005
Location: UK
Quote:
Originally Posted by marco_gea View Post
True, but then again, that's much less of an issue with large, high-efficiency woofers (T/S parameters change because of excursion - which is minimized by large size - and thermal compression - which is minimized by high efficiency)

Again, there's no fooling the laws of physics - despite what the marketing department of most commercial hi-fi manufacturers would have you believe.
Largely true, but unfortunately most people are not in such a happy position as to be able to use large, HE woofers.
__________________
www.wodendesign.com (commercial site)
www.frugal-horn.com www.frugal-phile.com (community sites)
  Reply With Quote
Old 29th April 2014, 12:14 PM   #57
perempe20 is offline perempe20  Hungary
diyAudio Member
 
perempe20's Avatar
 
Join Date: Feb 2008
Quote:
Originally Posted by fatmarley View Post
I have a pair of those in the shed and was thinking of doing a 3-way with them and the Scanspeak.
a two-way would also work. i heard it with a fixed Focal tweeter.
https://imageshack.com/a/5qwF/1
the other speaker with 2 5" drivers struggled, while the Monacor handled bass easily.
  Reply With Quote
Old 29th April 2014, 11:02 PM   #58
Ron E is offline Ron E  United States
diyAudio Member
 
Ron E's Avatar
 
Join Date: Jun 2002
Location: USA, MN
Quote:
Originally Posted by planet10 View Post
But, because of dynamic changes in T/S parameters, a vented box is mostly not properly aligned.
Any evidence for that claim? Why would it be better for an onken, or a TL?

Quote:
Originally Posted by fatmarley View Post
Couldn't the same be said of a sealed speaker? - your getting less output because you don't have a port.
There is a fuzzy boundary between leaky sealed and damped vented. It seems rather silly to put a vent in an otherwise sealed box if you are just going to remove its benefit?
__________________
Our species needs, and deserves, a citizenry with minds wide awake and a basic understanding of how the world works. --Carl Sagan
Armaments, universal debt, and planned obsolescence--those are the three pillars of Western prosperity. Aldous Huxley
  Reply With Quote
Old 29th April 2014, 11:25 PM   #59
planet10 is offline planet10  Canada
frugal-phile(tm)
diyAudio Moderator
 
planet10's Avatar
 
Join Date: Oct 2001
Location: Victoria, BC, NA, Sol III
I Hate Ported Speakers!!!
Quote:
Originally Posted by Ron E View Post
Any evidence for that claim?
Just look at all the times people say "my measures are different than the factory's". It is not that either measure is wrong, just that they are measured at a different point on the T/S curves.

Quote:
Why would it be better for an onken, or a TL?
I can't speak for an Onken, but our miniOnkens, with high vent resistance are certainly more tolerent, TLs, with a dominating 1/4 wave resonance are also.

dave
__________________
community sites t-linespeakers.org, frugal-horn.com, frugal-phile.com ........ commercial site planet10-HiFi
p10-hifi forum here at diyA
  Reply With Quote
Old 30th April 2014, 01:22 PM   #60
marco_gea is offline marco_gea  Italy
diyAudio Member
 
Join Date: Apr 2005
Location: London, UK
Default Theoretical (small signal) vs. REAL (realistic volume)

Quote:
Originally Posted by marco_gea View Post
True, but then again, that's much less of an issue with large, high-efficiency woofers (T/S parameters change because of excursion - which is minimized by large size - and thermal compression - which is minimized by high efficiency)

Again, there's no fooling the laws of physics - despite what the marketing department of most commercial hi-fi manufacturers would have you believe.

Marco
This is actually interesting, so I dug up some large-signal measurements ("Klippel") for a highly regarded mid-woofer typical of the ones employed in many "high-end" speakers today: the ScanSpeak 18W-4434g00: http://www.scan-speak.dk/datasheet/pdf/18w-4434g00.pdf

Measurements here: Scanspeak 18w/4434g00 Klippel Results

And then I went and simulated it in a reasonably optimized 30L / 40Hz Bass-Reflex box.

This is the result using the published (small signal) T/S parameters:
An externally hosted image should be here but it no longer works. Please upload images instead of linking to them to prevent this.


And THIS is the result when the same speaker in the same box is pushed to produce a 98dB peak at 3m (which corresponds to an 80dB mean listening level if one assumes an audiophile recording with a 18dB crest factor):
An externally hosted image should be here but it no longer works. Please upload images instead of linking to them to prevent this.


Not pretty, uh?

Little wonder that Bass-Reflex boxes get a bad rep!

Now let's repeat the simulations for a REAL high quality Woofer, shall we?

JBL 1501AL (15" AlNiCo magnet, underhung voice coil...), used in the flagship "Everest" system: JBL Master Reference Monitor - Page 33

Small-signal simulation in 120L / 35 Hz Bass-Reflex box:
An externally hosted image should be here but it no longer works. Please upload images instead of linking to them to prevent this.


...and at 98dB @ 3m:
An externally hosted image should be here but it no longer works. Please upload images instead of linking to them to prevent this.


For all intents and purposes, indistinguishable.

Meditate, folks, meditate...

Marco
Attached Images
File Type: png scan1.png (16.4 KB, 26 views)
File Type: png scan2.png (18.0 KB, 25 views)
File Type: png jbl1.png (14.8 KB, 24 views)
File Type: png jbl2.png (14.8 KB, 22 views)
  Reply With Quote

Reply


I Hate Ported Speakers!!!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
Measuring Ported Speakers ilardi Multi-Way 15 25th February 2012 09:14 PM
cheap ported speakers for a demo?!? head_unit Multi-Way 11 9th February 2012 06:47 PM
Big speakers in none ported enclosures. nigelwright7557 Multi-Way 6 23rd September 2008 12:32 AM
integrating subwoofers with ported main speakers keyser Multi-Way 11 15th March 2005 11:00 PM


New To Site? Need Help?

All times are GMT. The time now is 09:48 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.00%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Copyright ©1999-2020 diyAudio
Wiki