Speakerplans.com Homepage
Forum Home Forum Home > Other Chat > Golden oldies
  New Posts New Posts RSS Feed - Goodmans 18 HP xmax (etc... )
  FAQ FAQ  Forum Search   Events   Register Register  Login Login

Goodmans 18 HP xmax (etc... )
 Post Reply Post Reply Page  12>
Author
Message
  Topic Search Topic Search  Topic Options Topic Options
bob4 View Drop Down
Old Croc
Old Croc
Avatar

Joined: 29 February 2004
Location: Finland/Germany
Status: Offline
Points: 1924 		Post Options Post Options   Thanks (0) Thanks(0)   Quote bob4 Quote  Post ReplyReply Direct Link To This Post Topic: Goodmans 18 HP xmax (etc... )
    Posted: 04 January 2025 at 10:23am
Friend of mine has a couple of these old beasts kicking around. The brochures of yesteryear available on the net don't provide any parameters, probably because they predate the work of Thiele and Small. 

Does anyone on here have a vague idea of the xmax and xvar/xmech of the 18 HP? Iirc they claim 25 Hz resonance Shocked

Any input would be highly appreciated!

Power wise I am aware that they are frail, they will be driven with suitably specced amps (100-200w rms @8 ohm)

Apologies for the bad picture. Hopefully you can glean something despite the grill. 




Edited by bob4 - 04 January 2025 at 10:27am
Back to Top
jbl_man View Drop Down
Moderator Group
Moderator Group
Avatar

Joined: 12 January 2005
Location: London.
Status: Offline
Points: 11308 		Post Options Post Options   Thanks (0) Thanks(0)   Quote jbl_man Quote  Post ReplyReply Direct Link To This Post Posted: 04 January 2025 at 1:26pm
Goodmans 18p has a paper cone, and a doped paper surround. Xmax is irrelevant with these. Power handling was 100 watts at best, and given fifty-year old adhesives, 50w would be about the limit today. 3 inch voice coil.They are quite efficient for an 18-inch though. Was mainly intended to be a bass guitar/organ speaker, so has some useful lower-mid sounds.
 I did buy a couple of these new around 1976, were only about £45, those were the days! 
Be seeing you.
Back to Top
slaz View Drop Down
Old Croc
Old Croc
Avatar

Joined: 27 November 2009
Location: London E2
Status: Offline
Points: 2731 		Post Options Post Options   Thanks (0) Thanks(0)   Quote slaz Quote  Post ReplyReply Direct Link To This Post Posted: 04 January 2025 at 8:18pm
I have a couple of the 18HP in the shed .... both need a bit of attention. One has a small hole/rip in the cone (which I'm fairly sure could be repaired well) and the other has a terminal missing (but the tinsel wire is OK). I've tested both at very small power in free air, and both basically work. Not sure what to do with em - can't bring myself to chuck em .... any ideas anyone ? Re the 50-yo adhesives - yeah I hear you .... well - dunno. They've been stored in a totally dry, ventilated place. Mine are the HP version - prob a bit younger - 8ohms 230W is on the label.
REMEMBER....POLITICIANS AND DIAPERS SHOULD BE CHANGED OFTEN AND FOR THE SAME REASON
Back to Top
bob4 View Drop Down
Old Croc
Old Croc
Avatar

Joined: 29 February 2004
Location: Finland/Germany
Status: Offline
Points: 1924 		Post Options Post Options   Thanks (0) Thanks(0)   Quote bob4 Quote  Post ReplyReply Direct Link To This Post Posted: 04 January 2025 at 9:51pm
Here is another picture. They are Pro Power  series HP 18

Anyone care to share actual experiences of using these, what they are capable, what are the limits? For example, is there a risk of easily damaging the voice coil former with overexcursion? 

Does anyone know the dimensions of the voice coil, clearance from the pole plate etc........

I remember talk about using these in quad wardrobes, run off 600w kt88 tube amps..... they must move some air? 

Edit:  and furthermore, are these the frames people talk about being reconed by wembley speakers? 




Edited by bob4 - 05 January 2025 at 8:22am
Back to Top
jbl_man View Drop Down
Moderator Group
Moderator Group
Avatar

Joined: 12 January 2005
Location: London.
Status: Offline
Points: 11308 		Post Options Post Options   Thanks (0) Thanks(0)   Quote jbl_man Quote  Post ReplyReply Direct Link To This Post Posted: 05 January 2025 at 9:01am
That is the later model, the one i was refering to was the earlier 18p.  The one you have would have been mid-80s.
Yup, higher power rating. Will still be the same 3 inch coil i expect. 
Be seeing you.
Back to Top
Contour View Drop Down
Young Croc
Young Croc


Joined: 03 March 2004
Status: Offline
Points: 677 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Contour Quote  Post ReplyReply Direct Link To This Post Posted: 05 January 2025 at 10:10am
I would suspect 200-400 W RMS power would be fine for these. Old stuff, but quality, just use it. 
Back to Top
jbl_man View Drop Down
Moderator Group
Moderator Group
Avatar

Joined: 12 January 2005
Location: London.
Status: Offline
Points: 11308 		Post Options Post Options   Thanks (0) Thanks(0)   Quote jbl_man Quote  Post ReplyReply Direct Link To This Post Posted: 05 January 2025 at 10:20am
I have found the original 1984 brochure, it lists both the earlier 18p and later 18HP drivers.
Be seeing you.
Back to Top
Robbo View Drop Down
Old Croc
Old Croc


Joined: 05 December 2005
Location: Shropshire
Status: Offline
Points: 4297 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Robbo Quote  Post ReplyReply Direct Link To This Post Posted: 05 January 2025 at 11:04am
I seem to remember that the blue chassis 18P shown above was the basis for Wembleys own 18" sub range of cabinets from back in the seventies---IIRC they uprated both the voice coil and cone assembly to make them a much better driver compared to most on the market back then.
Back to Top
bob4 View Drop Down
Old Croc
Old Croc
Avatar

Joined: 29 February 2004
Location: Finland/Germany
Status: Offline
Points: 1924 		Post Options Post Options   Thanks (0) Thanks(0)   Quote bob4 Quote  Post ReplyReply Direct Link To This Post Posted: 05 January 2025 at 11:08am
Originally posted by jbl_man jbl_man wrote:

I have found the original 1984 brochure, it lists both the earlier 18p and later 18HP drivers.


Thank you for the link. This is the brochure/material I was referring to.
Meanwhile I simulated the suggested cabinet and slot port, and apparently this yields a box tuning of 35 Hz for the Power Pro 18 HP !!! Shocked
Back to Top
bob4 View Drop Down
Old Croc
Old Croc
Avatar

Joined: 29 February 2004
Location: Finland/Germany
Status: Offline
Points: 1924 		Post Options Post Options   Thanks (0) Thanks(0)   Quote bob4 Quote  Post ReplyReply Direct Link To This Post Posted: 05 January 2025 at 11:10am
Originally posted by Robbo Robbo wrote:

I seem to remember that the blue chassis 18P shown above was the basis for Wembleys own 18" sub range of cabinets from back in the seventies---IIRC they uprated both the voice coil and cone assembly to make them a much better driver compared to most on the market back then.

Thank you for this bit of information! So this might suggest that the internal magnet structure geometry is not per se a restricting factor in this case? 


Edited by bob4 - 05 January 2025 at 12:35pm
Back to Top
knet94 View Drop Down
Old Croc
Old Croc
Avatar

Joined: 31 March 2008
Location: NW London
Status: Offline
Points: 1538 		Post Options Post Options   Thanks (0) Thanks(0)   Quote knet94 Quote  Post ReplyReply Direct Link To This Post Posted: 05 January 2025 at 3:51pm
Nice trip down memory lane. I've still got 4 of the 15HPs. I always thought it odd that they were rated at 250 watts whilst the 18HP was 230 watts.
Back to Top
VECTORDJ View Drop Down
Young Croc
Young Croc
Avatar

Joined: 11 June 2006
Location: United States
Status: Offline
Points: 585 		Post Options Post Options   Thanks (0) Thanks(0)   Quote VECTORDJ Quote  Post ReplyReply Direct Link To This Post Posted: 09 January 2025 at 4:14pm
LOVE OLD SCHOOL GEAR...A+....VECTORSONICS
Back to Top
 Post Reply Post Reply Page  12>

Forum Jump Forum Permissions View Drop Down

Forum Software by Web Wiz Forums® version 12.08
Copyright ©2001-2026 Web Wiz Ltd.