Design a Bose-beater - Page 8 - 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 29th March 2005, 03:45 AM   #71
Wizard of Kelts
diyAudio Moderator
 
Join Date: Sep 2001
Location: Connecticut, The Nutmeg State
I am proposing a two way-I'll explain in a moment-with an Audax HM100CO woofer from Parts Express. Pricey, I know-$70 each. But you did say $600 for the whole system, correct?
Here are the specs:
http://www.partsexpress.com/pe/pshow...number=296-053

In a 4.5" cube, with 3/8" walls, the 4 inch HM100CO has 53 cu inches to work with. Let's call it 45 cu inch. This is inside a 4.5 in cube.

What are the advantages?

It will be 6 dB down at 140 Hz-right where you want it to be for a 140 Hz crossover.

It will be 89 dB @1M/1W-how much more efficient is that than the others?

It will have a Qtc of 0.65-somewhare in between critically damped and the traditional Qtc of 0.7.

Here is the curve for the woofer:
Attached Images
File Type: gif audax hm100co 4.gif (4.8 KB, 1027 views)
__________________
"A friend will help you move. A really good friend will help you move a body."
-Anonymous
  Reply With Quote
Old 29th March 2005, 03:50 AM   #72
Wizard of Kelts
diyAudio Moderator
 
Join Date: Sep 2001
Location: Connecticut, The Nutmeg State
Oh, yes-forgot to add. The 4" has about twice the cone area of a 3". Aperiodic loading adds very little output out the port. So the 4" only has to move half as much to produce the same output level as a 3". This muddies the uppermidrange and highs less.

The less a cone has to move to produce the same SPL in the bass, the cleaner the upper mids and highs that speaker must carry.

Now for the tweeter-which means even less intermodulation distortion.
__________________
"A friend will help you move. A really good friend will help you move a body."
-Anonymous
  Reply With Quote
Old 29th March 2005, 04:03 AM   #73
Wizard of Kelts
diyAudio Moderator
 
Join Date: Sep 2001
Location: Connecticut, The Nutmeg State
Here is it is:
http://www.partsexpress.com/pe/showd...number=275-030

It's outside diameter is only about 1.5" . that should mean that if you move the 4 inch over to one corner of the 4.5" front of the cube, this tweeter ought to come close to being able to fit diagonally in one of the top corners. I haven't drawn up the front face yet, but I believe that it will come close enough to fitting tso that at most, you wold only have to adjust the front face dimensions marginally to make it work.

You are asking the satellite midwoof to do quite a lot-move air from 140 Hz up to the upper reaches. The more the midwoof must strain to reproduce the midbass notes, the more muddied the upper mids.

Paul Klipsh's monumental article-Intermodulation Distortion in Loudspeakers-available through Email by request. I consider it on a par with the Thiele-small papers.

so any tweeter you include with this will give welcome relief to the speaker trying to reproduce the sound from 140 Hz on up. this tiny little number will give relief from 3,500 on up. And it costs 5 bucks.

No, I have not tried it, but any competent tweeter will give welcome relief to this system which has a 4" midwoof carrying the load from 140 Hz on up.
__________________
"A friend will help you move. A really good friend will help you move a body."
-Anonymous
  Reply With Quote
Old 29th March 2005, 04:13 AM   #74
diyAudio Member
 
Join Date: Apr 2004
Location: Costa Rica
Send a message via AIM to johninCR Send a message via MSN to johninCR Send a message via Yahoo to johninCR
I still say don't try to compete with Bose size wise. She's unlikely to really appreciate the sonic difference. Do something artsy and get her involved in the design, if you can't come up with something you'll know she'll love on your own. She'll appreciate those speakers forever and remember you for them whether you're still together or not. Don't try to beat Bose at their own game. We know you can, but in her eyes you won't.

Test the waters if you don't believe me. Throw a couple of cool art related ideas her way and you'll get "oh, you can really do that" instead of "did you know that strawberries are in season?"
__________________
Everyone has a photographic memory. It's just that most are out of film.
  Reply With Quote
Old 29th March 2005, 04:26 AM   #75
JZatopa is offline JZatopa  United States
diyAudio Member
 
Join Date: May 2003
Location: Chicago
If you want to make this system sound halfway decent down low I would suggest two small subs in a stereo arangement run in stereo. If you do this you will be able to get a symetrical look to the setup, you can run the subs higher so that you get a full sound from the front speakers, and you will be able to use a little bit smaller drivers due to the fact their will be two of them. I would personaly recomend a sealed 8" enclosure. You could shape them any way you want and you will get great sound as long as you use a quality driver.

If it has to be hidden then I suggest the largest sub you can fit where you are going to hide it. I personaly would still go sealed.
  Reply With Quote
Old 29th March 2005, 04:29 AM   #76
Wizard of Kelts
diyAudio Moderator
 
Join Date: Sep 2001
Location: Connecticut, The Nutmeg State
John in CR might have a point there, but for the intellectual exercise I would like to see how, with just a little expansion in the volume department, we can beat Bose. Besides, the 4.5" cube has less volume than two of those cubes together.

Just to give you an idea of how good this is: the 4" can move 0.64 cu inch of air. At 140, where it crosses over, that's about 100 dB SPL, more or less.

But at the crossover point, it should be about 6 dB down from the midband. So the midband output should be about 105 or 106 dB SPL.

That is mighty fine output even for larger systems, let alone a 4.5 inch cube. The trick, of course, is that crossover point. If we crossed over at 100 Hz, we can deduct 6 dB from that figure.

Making a high crossover point-but not as high as Bose's-lets us get surprising performance from a tiny box. And 140 is considered a good crossover point even among hifi aficionados. 200 Hz is not.
__________________
"A friend will help you move. A really good friend will help you move a body."
-Anonymous
  Reply With Quote
Old 29th March 2005, 04:39 AM   #77
diyAudio Member
 
Join Date: Jul 2003
Location: Silicon Valley
Quote:
Originally posted by kelticwizard
Paul Klipsh's monumental article-Intermodulation Distortion in Loudspeakers-available through Email by request. I consider it on a par with the Thiele-small papers.
Please send it. Let's use this one: jdadson at yahoo.com
__________________
Davy Jones
  Reply With Quote
Old 29th March 2005, 04:47 AM   #78
diyAudio Member
 
Join Date: Apr 2004
Location: Costa Rica
Send a message via AIM to johninCR Send a message via MSN to johninCR Send a message via Yahoo to johninCR
It doesn't take an intellectual excercise to beat Bose. It takes marketing. Go audition boom boxes or computer speaker systems and you'll beat Bose for only $100 or less. Or take the same size cab, put better drivers in and reinforce the cab and that will beat Bose. Sure you can go thru the gyrations to get the best sound possible out of the same size, but why? We all know that if you take the same components and put them in a larger cab with a real front baffle, the larger version of the same components is going to sound better.
__________________
Everyone has a photographic memory. It's just that most are out of film.
  Reply With Quote
Old 29th March 2005, 05:10 AM   #79
Wizard of Kelts
diyAudio Moderator
 
Join Date: Sep 2001
Location: Connecticut, The Nutmeg State
John:

Well, in this case the 4.5" cube is smaller than the two Bose cubes stacked upon each other, so I wouldn't even be increasing the volume to get markedly better sound.

I think there is something to be said for taking on the big boys and seeing what you can do. In this case, the main thing Bose has going for it is smallness of size. It universally agreed upon by all, even by defenders of Bose 901's, that the Bose AV systems should have "Playskool" written on them and be stocked in the crayon department of your local Wal-Mart.

So the fun is in seeing if you can make take something the same size and actually produce a sound system of some quality. I feel that was Dave's intention in starting this thread, and various people have given good suggestions toward that goal. Don't you agree?
__________________
"A friend will help you move. A really good friend will help you move a body."
-Anonymous
  Reply With Quote
Old 29th March 2005, 05:43 AM   #80
diyAudio Member
 
Join Date: Aug 2004
Location: IL
Some thoughts that have come to mind while reading this:

Making small sats, similar to Bose, is going to be hard to get good sound out of. Remember, those Bose cubes use paper-thin ABS, not 1/2 inch MDF. You're already losing about an inch on all sides alone from that. When we're talking about sizes on this scale, an inch on all sides is a good amount.

Plus, 140 Hz crossover point, if we want to talk good sat/sub systems, is not good, at all, IMO. Sound starts to become really directional around 150-160 Hz. If you have a second-order crossover point to the sub at 140 Hz, you'll definitely be hearing voices coming out of the sub, or at the very least be able to pick it out of the room, almost completely defeating the point of a sat/sub system.

It's generally recommended to have your sub down at least 12 dB at 160 Hz. That means a second-order crossover point at 80 Hz or lower. Hence why THX standards require main speakers to go down to at least 80 Hz.

So, I would pull away from the 140 Hz crossover point. In the sat/sub system I'm building where size is very limited, I'm doing 100 Hz.

But in your case, I would strongly agree with the idea of integrating the speakers into the room as art. This is really where you can get the full benefit of DIY! I've always wanted to do a transmission line with small woofers, and use the speaker stand, in my thoughts a PVC pipe, as the line.

If I were you, I'd get away from the small sat idea and go towards the art idea. Give her some ideas, or even let her design it! If that doesn't work, then just get the Bose cubes. After all, it's for ambient music for the studio, right?

My 2 cents.

Reece
  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
Bose 901 design 901Fixer Multi-Way 33 1st April 2013 07:12 PM
Harmon Kardon HD-970 modded, a world beater? Nigel Page Digital Source 125 16th May 2010 09:06 PM
Bose PAS like raintalk Multi-Way 16 24th December 2004 12:32 AM
Was Bose right all along? navin Multi-Way 50 18th June 2004 03:13 PM


New To Site? Need Help?

All times are GMT. The time now is 11:17 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