Goldwood 18" for OB sub - diyAudio
Go Back   Home > Forums > Loudspeakers > Multi-Way
Home Forums Rules Articles diyAudio Store Gallery Wiki Blogs Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

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
Thread Tools Search this Thread
Old 15th March 2004, 04:56 PM   #1
diyAudio Member
Join Date: May 2002
Location: Los Gatos, CA
Default Goldwood 18" for OB sub

Well I was playing around (for the first time) with the xbaffle open-baffle spreadsheet to see how the Fostex FE206E and the 18" Goldwood GW-1858 driver looks for open baffle use. _Here are my results. _The Goldwood driver looks promising, at least compared to the emminence driver. _The FE206E obviously does not have any low end in an open baffle. I'm not sure how accurate this spreadsheet is to real-world results/sound. _A crossover point of 200hz looks like a good starting point for the Goldwood. _If the FR graph is to be believed, that 104db bump at 45hz of the 1858 compensates nicely for the low end drop off when used in an open baffle.

Room Response:
Frequency response:

spec's and baffle sizes used for calculations...

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _Fostex _ _ _Goldwood _ _ _Eminence
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _FE206E _ _ _GW-1858 _ _ _Gamma Pro 15CX
Driver Resonant Frequency (Fs - Hz): _ _ _39.00 _ _ _30.00 _ _ _43.00
Driver Electrical Q (Qes): _ _ _ _ _ _0.18 _ _ _1.07 _ _ _1.00
Driver Mechanical Q (Qms): _ _ _ _ _ _3.73 _ _ _6.65 _ _ _6.55
Driver Equiv Volume (Vas - liter): _ _ _54.53 _ _ _524.00 _ _ _225.00
Thermal Power Limit _ (P - VA): _ _ _ _ _ _90.00 _ _ _220.00 _ _ _200.00
DC Resistance _ _ _ _(Re - Ohm): _ _ _6.69 _ _ _6.20 _ _ _5.80
Pk-to-Pk Excursion (Xmax - mm): _ _ _ _ _ _1.50 _ _ _3.36 _ _ _8.00
Effective Cone Dia. _ (D - mm): _ _ _ _ _ _162.00 _ _ _406.00 _ _ _350.00
Baffle Width (mm) _ _ _ _ _ _ _ _ _ _ _380 _ _ _750 _ _ _750
Hight above floor (mm) _ _ _ _ _ _ _ _ _ _762 _ _ _618 _ _ _618
Dist. rear Wall (mm) _ _ _ _ _ _ _ _ _ _1618 _ _ _1618 _ _ _1618
Dist. side Wall (mm) _ _ _ _ _ _ _ __ _ _1000 _ _ _1000 _ _ _1000
  Reply With Quote
Old 15th March 2004, 05:17 PM   #2
diyAudio Member
Join Date: Jan 2004
Location: Virginia, USA
You may also want to look at Studio Pro 18" PW1808-US, lower Fs, higher x-max, although it does have a bit lower Qts...

  Reply With Quote
Old 15th March 2004, 05:26 PM   #3
sreten is offline sreten  United Kingdom
diyAudio Member RIP
Join Date: Nov 2003
Location: Brighton UK
Hi BB,

I'm a little confused.

How did you arrive at the huge bump at 45Hz, with a
driver supposedly having a Qts of ~1.1 at 30Hz ?

  Reply With Quote
Old 15th March 2004, 11:44 PM   #4
diyAudio Member
mikee12345's Avatar
Join Date: Nov 2002
Location: NZ
What about the dayton 15" ib woofer with 14mm xmax? it will have much more Vd than a tiny xmax 18" of cheaper quality.

If i could fit an IB,or dipole and amps,id try this out due to people here loving the sound of dipoles :-D

dayton 15"

Excuse my sillyness-but WHICH graph do i take note of!
there are 3 the same...

because the FR (onewoofer) looks good,yet the graph on the driver input page,and room response looks bad...

  Reply With Quote
Old 16th March 2004, 12:29 AM   #5
diyAudio Member
Join Date: Dec 2003
Location: San Diego, CA, USA
I'd be concerned with the low xmax of the goldwood. You might want to calculate how much SPL you can get with the goldwood before you run out of travel. i suspect it wouldn't take much power at all to run out of xmax at 30Hz or so.

This is very similar to what I've been planning -- Fostex FE206E along with an Eminence Kilomax-18. I've got the eminence running with right now with some temporary mids and a tweeter. The Kilomax is moving a fair amount -- way more than 4 mm.

- Robert
  Reply With Quote
Old 16th March 2004, 12:43 AM   #6
diyAudio Member
Join Date: May 2002
Location: Los Gatos, CA
I "arrived" at the bump by looking at the response graph that Goldwood sent me. You can see it by clicking on the "104db bump" link I posted above.

I saw that Pyramid Studio Pro driver, and yes it also looks good. I could not find a response graph for it though, or who to send an email to in order to get it (like I did for Goldwood). Anyone know where is the Pyramid home page?

That Dayton driver is too inefficient for my taste.

I'm not so concerned with the xmax as I'm planning on running 2, or maybe 4 drivers total, so things would have to get aweful loud before I start hitting the xmax limit.

The Kilomax driver looks good, but I question if it's worth the extra money, when you can get 4 of the goldwood drivers for less. I'm not convinced that you have to spend allot on drivers for open baffle use. Also, what's it's efficiency, I couldn't find it? And the FR graph doesn't plot the impedance - though the Zmax is quite high.

I may put a couple other drivers through the spreadsheet and see what happens. Or, someone else could do it for the Kilomax, and Pyramid?
  Reply With Quote
Old 16th March 2004, 01:28 AM   #7
diyAudio Member
Join Date: May 2002
Location: Los Gatos, CA
Here's the comparison of the Pyramid driver to the Goldwood via the spreadsheet. They performance looks almost identicle (as is their price), in this sim/spreadsheet anyway...

Frequency Response:

In-room (whatever this is really representing?)...

For me the interesting thing is if the Pyramid driver's Le as low as the Goldwood (.6 mH)? And what does the Pyramid impedance plot look like? Zmax?

Data for the sim...

XL-Baffle Version 0.9 - prerelease version
Fostex 8" Goldwood 18" Pyramid 18"
FE206E GW-1858 Studio Pro
Driver Resonant Frequency (Fs - Hz): 39.00 30.00 24.56
Driver Electrical Q (Qes): 0.18 1.27 0.91
Driver Mechanical Q (Qms): 3.73 6.65 8.12
Driver Equiv Volume (Vas - liter): 54.53 524.00 900.00
Thermal Power Limit (P - VA): 90.00 220.00 325.00
DC Resistance (Re - Ohm): 6.69 6.20 7.20
Pk-to-Pk Excursion (Xmax - mm): 1.50 3.36 4.60
Effective Cone Dia. (D - mm): 162.00 438.00 438.00
Baffle Width (mm) 380 750 750
Hight above floor (mm) 762 618 618
Dist. rear Wall (mm) 1618 1618 1618
Dist. side Wall (mm) 1000 1000 1000
  Reply With Quote
Old 16th March 2004, 02:05 AM   #8
diyAudio Member
Join Date: May 2002
Location: Los Gatos, CA
Here a comparison of Goldwood, Pyramid, and Eminence (Kilomax) 18" drivers...

Although the Kilomax can handle tons more power, it doesn't look to be the best choice for open baffle bass response (if this spreadsheet is to be believed). The proof is in the hearing though - and baffle construction.

Again, given these are all "pro" drivers, they are ALL made to handle much more power than I believe they will see for audio use, at least in MY house. Especially since I will be running more than just one - ie, not just a single subwoofer.

I'm really hoping that this bears out, as it would be nice if you can get away with $70 drivers instead of $300 drivers for open baffle use.
  Reply With Quote
Old 16th March 2004, 02:56 AM   #9
DeonC is offline DeonC  South Africa
diyAudio Member
DeonC's Avatar
Join Date: May 2002
Location: Kimberley, South-Africa
Hi Brad

Have you considered the Goldwood GW215 15" drivers? When you compare them to the GW1858 in XL Baffle, they model flatter in the bass region than the 1858 (due to a higher Q). ITO peak SPL the 18" drivers give only about a 6dB advantage, but at the expense of a rising response. In the low bass there is little to choose between them. Here's the kicker though: the GW215 drivers cost only US$23 each at PartsExpress if you take more than four (which I assume you will be doing), so you can get THREE GW215s for the price of one GW1858. As long as space is not an issue (which it doesn't seem to be as you're contemplating more than one 18" driver per side) I think that the GW215 will be better suited to your needs. Three GW215 drivers are sure to be superior to a single GW1858. If you have the space you can mount six GW215 drivers per side on a baffle that will be about 8.5 feet tall . The cost will be the same as two GW1858 drivers per side, and should sound better (not too mention look a LOT meaner ).

I don't suffer from insanity. I enjoy every minute of it.
Have a look at my favorite thread: Interesting YouTube video clips
  Reply With Quote
Old 16th March 2004, 05:56 AM   #10
OMNIFEX is offline OMNIFEX  Jamaica
diyAudio Member
OMNIFEX's Avatar
Join Date: Mar 2003
Location: Locked Up In The Amp Rack

I'm a person that appreciates 18 drivers. With that being
said, I think you would be making a mistake going for the Goldwood 1858.

Eminence will stand by their published specs. Will Goldwood
do the same?

I understand you want an open baffle type bass system.

However, Goldwood 1858 has a no. of 0.873%, with a
xmax of 3.36 mm, where as the Eminence Killomax 18
has an no. of 1.433, and, an xmax of 9.8 mm

So, two Goldwood 1858's will be a tad under one Eminence
Killomax 18. This is of course Goldwood's TS Parameters
are correct.

Companies can get away making a cheap 15, 12, 10, and,
8 inch woofer. But, they can't with a 18, 21, or 24 inch
  Reply With Quote


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
Goldwood G-8003 8" Fullrange Carlp Full Range 16 3rd August 2013 03:46 PM
anyone has experience with goldwood 10" woofers ? angeloitacare Multi-Way 0 6th January 2008 05:28 PM
Goldwood 15s on OB? Pano Multi-Way 0 6th January 2007 06:23 AM
8" 4 ohm heavy duty woofer/midbass needed, who's Goldwood? eRiCdWoNg Multi-Way 11 29th February 2004 06:11 PM

New To Site? Need Help?

All times are GMT. The time now is 11:26 PM.

vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright 1999-2017 diyAudio

Content Relevant URLs by vBSEO 3.3.2