Noob needing advice - Driver cost vs Sound Quality Estimates - Page 5 - diyAudio
Go Back   Home > Forums > Loudspeakers > Multi-Way

Multi-Way Conventional loudspeakers with crossovers

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 19th February 2013, 04:15 PM   #41
jReave is offline jReave  Canada
diyAudio Member
 
Join Date: Oct 2012
No argument that passive xo's can get quite expensive if you choose to go with those big name parts. And if the parts count starts getting out of hand too.

However, to suggest that something like the .4ohms resistance of a single coil in a woofer circuit is going to result in such massive insertion losses that a much more powerful amp is required is a bit of an exaggeration, don't you think?

Perhaps what would be helpful is a comparison of the costing of the actual active components that will be necessary for the OP intended application vs those in a passive xo. For the latter of course, we'll have to wait until a complete simulation is completed before that can be done. I'm not sure if that is also the case for an active set-up.
  Reply With Quote
Old 19th February 2013, 04:26 PM   #42
diyAudio Member
 
Join Date: Sep 2011
I've been looking at the hypex amps for an active system. The look awesome but I wish the availability in the US was a bit easier.

I'm still doing a lot of reading on speaker design. I really liked the combo previously posted and the price wasn't bad. Newtronics Temperance III. I really wish I had a chance to listen first though; anybody had any experience with them directly? The other concern I started having was thinking about a matching center channel as they are dual purpose (more music the movies though) and designing a matching unit.
  Reply With Quote
Old 19th February 2013, 05:03 PM   #43
jReave is offline jReave  Canada
diyAudio Member
 
Join Date: Oct 2012
mstang, if you seriously have a budget of a $3000 for the front pair, want to re-create or surpass the S8's, if you have the woodworking skills and facilities required and wish to possibly extend the design to front and rear channels, then I think you'd be making a mistake going for something like the Temperance.

I have no doubt that's probably a good sounding speaker, but knowing Paradigm's reputation and the fact that the S8's are their top-of-the-line speakers, I don't think it will come that close to beating it for SQ. (could be wrong of course) Something like the Elsinores (Elsinore Speakers DIY ) would probably come a lot closer (altho I find them to have about 0 aesthetic appeal) but with your budget and starting from scratch, I think you can still do better than that. And I think you could probably do this with either active or passive xo's depending on which way you want to go.

Give me a little time - I am researching some potential drivers that will work within your desired configuration and that should equal or surpass your objectives while still staying within your budget. My thinking is that for $3000, you should actually be able to come up with a set of jaw droppingly-good speakers.

And it's the drivers that are going to make all the difference in terms of achieving your goals. Just take the S8's beryllium tweeter for example. That's one hot tweeter material these days and you can be sure that Paradigm has implemented it well. You should be looking at a *very* good tweeter for your design if you want to be thinking of close to the same results.
  Reply With Quote
Old 19th February 2013, 05:44 PM   #44
diyAudio Member
 
Join Date: Nov 2009
Location: Birmingham, UK
Quote:
Originally Posted by jReave View Post

However, to suggest that something like the .4ohms resistance of a single coil in a woofer circuit is going to result in such massive insertion losses that a much more powerful amp is required is a bit of an exaggeration, don't you think?
Lets just look at the impedances without DCR of the series inductor in a simple
12dB L-R passive crossover crossing at 2000Hz using 8Ohm drivers:
The textbook series inductor value for the low pass is 1.27mH

Impedance at 1500Hz is 11.96 Ohm, at 1000Hz it is 7.98 Ohm, at 500Hz it is 3.98 Ohm, at 250Hz it is 2 Ohm and at 125Hz it is 1 Ohm.

DC resistance has got to be added to these values.


The impedance of the textbook 4.98microF series capacitor for the high pass is 12.78 Ohm at 2500Hz, 7.98 Ohm at 4000Hz, 3.99 Ohm at 8000Hz and 2 Ohm at 16000Hz.
  Reply With Quote
Old 19th February 2013, 06:10 PM   #45
jReave is offline jReave  Canada
diyAudio Member
 
Join Date: Oct 2012
Sorry, but I'm still not sure how this is germane to the OP?

He's got 2 x 500W monoblocks to power his proposed mains. Are you saying that if he uses passive xo's that he won't have enough power for perhaps an 88-90dB speaker?

To reach say 100dB SPL's?
  Reply With Quote
Old 19th February 2013, 06:37 PM   #46
diyAudio Member
 
Join Date: Nov 2009
Location: Birmingham, UK
It is germane to your post in which you said that the insertion loss of a passive crossover equals the inductors DCR and no more which does seem incorrect.
  Reply With Quote
Old 19th February 2013, 06:46 PM   #47
diyAudio Member
 
Join Date: May 2010
Location: MN
But you just listed a bunch of impedance numbers that indicate a filter being a filter. That's not insertion loss, it's filtering. Insertion loss is negligible except in speakers with a TON of additive DCR in the crossover. What requires bigger/better amps is high electrical phase angle, which depends on the crossover design.
  Reply With Quote
Old 20th February 2013, 09:42 AM   #48
diyAudio Member
 
Join Date: Nov 2009
Location: Birmingham, UK
Quote:
Originally Posted by dumptruck View Post
But you just listed a bunch of impedance numbers that indicate a filter being a filter.
3 octaves below and above crossover point?
  Reply With Quote
Old 20th February 2013, 06:45 PM   #49
diyAudio Member
 
Join Date: May 2010
Location: MN
Quote:
Originally Posted by Charles Darwin View Post
3 octaves below and above crossover point?
Yes, three octaves but the numbers you listed only happen when you put the inductor in a circuit by itself. When you add the 8Ω load that you described, it's a different story. The impedance of the idealized 1.27mH / 4.98uF / 8Ω resistive 2nd order system you suggested is attached, and it corresponds to the filter exactly. No insertion loss until you start adding DCR / ESR.
Attached Images
File Type: gif temp.gif (11.5 KB, 49 views)

Last edited by dumptruck; 20th February 2013 at 06:49 PM.
  Reply With Quote
Old 21st February 2013, 06:33 PM   #50
jReave is offline jReave  Canada
diyAudio Member
 
Join Date: Oct 2012
OK, back to trying to get your speakers built. (Warning: long posts ahead)

First, understand that instead of going active, you can actually get some help from the experts in the on-line community to model your design and produce a specific passive xo for your intended application (see this current thread for eg Design me a crossover and I'll build it ). If the xo is designed properly, you can still make small mid and/or tweeter level adjustments by ear or with free on-line test tones and a cheap SPL meter once the speakers are in your own environment.

Note that one little thing that might help you succeed at this is locating a fellow diyer in your area with measurement gear that would be willing to measure your speakers once the cabinets with drivers are built but without any xos designed yet. This will add an extra degree of accuracy to your project, although the simulation process is actually quite good and can produce outstanding results.

To increase the probability of achieving this, I would suggest expanding the number of people you have access to by also starting a similar thread on a second forum, Tech Talk Forum

And full disclosure, Ive been at this for a number of years but Im still far from being an expert. I can help you along the way but Ill still be relying as well on some help and confirmation from others.

OK, I wanted to answer the last question from your original post first.

Re the RTi6s, just pick a suitable 2-way project with an F3 in the 50Hz range from any of the following sites and that meets the budget, pretty much all of them have very good SQ:

Perhaps the Overnight Sensations, or the Hitmakers? https://sites.google.com/site/undefinition/diy
Veepers would be an excellent choice. Build Gallery
This one is also highly praised. Continuum, Pr
Zaph|Audio

Btw, if you havent found Zaphs site yet, bookmark it and start reading, especially if you want to shed some light on how to select drivers when youre unable to hear them first.

Cheers
jR
  Reply With Quote

Reply


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
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Noob/Neo needing sound advice... kutnupe8 Multi-Way 3 10th September 2011 01:25 PM
Noob needing help. icor1031 Subwoofers 43 26th March 2011 12:41 AM
Noob needing sub for gigs. mrbobian Subwoofers 20 7th May 2008 09:57 AM
Advice on highest quality full range driver deandob Full Range 39 13th December 2005 01:45 PM
Noob - Needing help deciding what Gainclone design to use tsnyder41 Chip Amps 5 19th May 2003 11:54 PM


New To Site? Need Help?

All times are GMT. The time now is 12:29 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2