Replacing vintage stereo speakers - 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 7th March 2004, 10:48 AM   #1
giacomo is offline giacomo  United States
diyAudio Member
 
Join Date: Mar 2004
Location: Astoria, NY
Default Replacing vintage stereo speakers

Hi there,

I've been fixing up an old stereo hi-fi console from the 50s and want to replace the speakers. It's a simple 2-way system but I want to put in better speakers than the ones that are in there. I know nothing of speaker design so any input would help.

First, I'm limited to the size. The woofer has to be 12" and the tweeter can be either 3.5" or I suppose I can go up to 4". From what I can tell, they're connected by some kind of simple condenser/crossover. I do not know the freq range of the speakers but I do know that the speakers are 9ohm (woofer) and 4ohm (tweeter).

So what I'm looking for is some idea of what I need without a lot of involved math. I've looked for kits online but have turned up nothing with this size combination. I'm not interested in price range right now but really what I should be looking for. What should be the ceiling on my woofer (40hz - 2000? 3500? 4000?) and what should be the bottom of my tweeter (2000?) What sort of crossover do I need between? (generically speaking) Do the freq controls on the console have any bearing on this on my selection? (I'm guessing no)

Again, any help would be appreciated.

Kind regards,
Giacomo
  Reply With Quote
Old 7th March 2004, 05:05 PM   #2
Variac is online now Variac  United States
diyAudio Editor
 
Variac's Avatar
 
Join Date: Dec 2001
Location: San Francisco, USA
Are they in a box like structure? ie, are they in a box, even if the box is part of the structure of the consule?
If so, what is the internal size of the box?

Is there a vent or port in the box area? ie a hole in the front or back without a driver?


Do you know what brand the existing drivers are?
  Reply With Quote
Old 7th March 2004, 05:19 PM   #3
sreten is offline sreten  United Kingdom
diyAudio Member
 
Join Date: Nov 2003
Location: Brighton UK
I don't want to put a dampener on this but if the original units
are still working there are those that would be appalled if you
changed them (people who like vintage drivers).

If you want to change them planet10 seems to be the expert
in this area. A Tangband 3" or 4" unit sealed off and a 12"
unit 6dB more sensitive than the TB crossed over first order
near the baffle step frequency seems to be the way to do it.

IMO this will be much better than the vintage units.

sreten.
  Reply With Quote
Old 7th March 2004, 05:32 PM   #4
giacomo is offline giacomo  United States
diyAudio Member
 
Join Date: Mar 2004
Location: Astoria, NY
Thanks for the reply.

From more research that I did this morning, I presume the setup I have now is serial. There is no brand marking on the speakers. The console is a Voice of Music from 1959 and as they went out of business some thirty years ago, it's a bit difficult to find out if the speakers were made by VM or if they were build by a third party for them. I have a repairman's schematics for the whole unit, but there is very little info on the speakers themselves.

I have plenty of room to work with on the inside of the cabinets. Unlike most of the 50s consoles, these speakers are separate from the amp/turntable. On the inside is actually another piece of wood that can be removed from the cabinet. It is this piece that holds the speakers. It is possible for me to cut another piece of wood with different size holes for any configuration, but as I'm an apartment dweller, I'm unsure if I want to undertake this right now.

I've been informed by another VM enthusiast that I should be presenting 8ohms to my amp. So if I want to keep this in a series, that means I have to get two 4 ohm speakers, correct? Or if I want to go parallel, then I will need to get two 16ohm. Am I on the right track here?

I'm still unsure about the capacitor between the two speakers. Based on what speakers I buy, how do I know figure what capacitor to use? I'm presuming that it's this capacitor that filters my low frequencies to my tweeter, correct?

If you can think of any good setup for a tube amplifier, and considering that I have room to work (plenty of room for a crossover if that's the way to go) please post.
  Reply With Quote
Old 7th March 2004, 05:43 PM   #5
giacomo is offline giacomo  United States
diyAudio Member
 
Join Date: Mar 2004
Location: Astoria, NY
Default follow up

Just read the post from sreten. Yes, usually I wouldn't try to change the speakers. I have a 67 fender vibrolux amp that would be pure desecration if I changed over, but I don't think the speakers for the console were the absolute best from the era. They are pemanent magnet and I know that on the whol (but correct me if I'm wrong) that pm's usually don't have good response. The console is so well made (real walnut, great tube amp) that I think that's where they cut corners.

Thanks and kind regards,

Giacomo
  Reply With Quote
Old 7th March 2004, 07:21 PM   #6
Variac is online now Variac  United States
diyAudio Editor
 
Variac's Avatar
 
Join Date: Dec 2001
Location: San Francisco, USA
P 10 would also be able to tell him if the existing drivers are decent or not. Thats why I asked what brand they were.

Where is that guy?......

an Eminence beta might be a good 12" to use...


A photo could help...
  Reply With Quote
Old 8th March 2004, 03:19 AM   #7
Variac is online now Variac  United States
diyAudio Editor
 
Variac's Avatar
 
Join Date: Dec 2001
Location: San Francisco, USA
Since the 2 drivers for each channel are crossed over to do different parts of the spectrum, usually you would use 2 8 ohm drivers per channel. Now if they are run in parallel without a crossover, then you would need 2 16 ohm I guess, but I suspect that is not the case. The tone controls have nothing to do with things as you suspected. You are still unclear about the speaker box. Is it open on the back?

You would help yourself a whole lot if you take photos of the speaker box from front and back , and close ups of front and back of the drivers.


Anyway we need Planet 10 here- where is he when we need him? but he needs photos too.
  Reply With Quote
Old 8th March 2004, 12:43 PM   #8
giacomo is offline giacomo  United States
diyAudio Member
 
Join Date: Mar 2004
Location: Astoria, NY
Variac,

Thanks for your continued interest. I've posted a pic of the drivers that are in there now. Check the next post for the enclosure.

I hooked up a pair of Event 20/20 studio monitors to the power amp but they're rated 4 ohm. I know this is not supposed to be good for the amp. The sound is definitely not as clear as with the original speakers. A bit muffled. Could this be from the impedence difference?

I've been looking into those eminence speakers. I'll presume from your suggestion that they are are good value. What do you think about the tweeters? Here's where I'm confused - should the tweeter range pick up where the woofer leaves off (5k for the betas) or is it all right to go lower (say, a bottom of 3.5 or 4k) Then there's the capacitor or crossover to consider too.

You've been a great help so far!

Thanks and kind regards,

Giacomo
Attached Images
File Type: jpg dscf0099.jpg (64.3 KB, 1506 views)
  Reply With Quote
Old 8th March 2004, 12:44 PM   #9
giacomo is offline giacomo  United States
diyAudio Member
 
Join Date: Mar 2004
Location: Astoria, NY
And here's the open enclosure
Attached Images
File Type: jpg dscf0096.jpg (76.3 KB, 1491 views)
  Reply With Quote
Old 8th March 2004, 02:51 PM   #10
sreten is offline sreten  United Kingdom
diyAudio Member
 
Join Date: Nov 2003
Location: Brighton UK
I don't think a PA type speaker using the Eminence Beta is a
good idea, its only around 90dB/W in the bass and has a
strongly rising axial output in the midrange.

http://www.partsexpress.com/pdf/290-408.pdf

This bass unit looks decent if your cabinets are big :

http://www.partsexpress.com/pe/pshow...number=295-320

This should have a sensistivity of around 89dB in box,
mate this to a mid/treble driver, e.g. :

http://www.partsexpress.com/pe/pshow...number=264-814

Use a first order series crossover set at around 250Hz.
(~ 90uF and 4.5mH calculated with 7R)

Or alternatively use a parallel network say 5mH with the
bass unit and simply use a capacitor to protect the TB
from low bass, you need to experiment here, but I'd
guess about 250uF.

Stuff the box, there is no need to seal off the smaller driver.

Your other option for a 12" bass unit is a full 3-way design.

A 12" two way with a normal tweeter is not a good idea.

I think there are better TB units not sold by PE,
as I said I'm no real expert at this.

sreten.

(illustration is for 1Khz c/o)
Attached Images
File Type: png 1st order.png (2.6 KB, 1439 views)
  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
Replacing tweeter in vintage speaker halfgaar Multi-Way 1 27th December 2007 04:42 PM
vintage stereo ddoyle Everything Else 4 28th February 2007 02:34 AM


New To Site? Need Help?

All times are GMT. The time now is 07:41 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