Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Instruments and Amps Everything that makes music, Especially including instrument amps.

Most guitar cabs designed poorly?
Most guitar cabs designed poorly?
Most guitar cabs designed poorly? 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 October 2019, 08:31 PM   #51
Mario Pankov is offline Mario Pankov  Europe
diyAudio Member
 
Join Date: Aug 2007
Location: Sofia
Most guitar cabs designed poorly?
Made some progress today (I would be done if I missed 4 screws of the right size...). The vintage looks did turn as I wanted it, I think it is ugly. Bauhaus plywood was water resistant and they didn`t state it when I bought, paint didn`t adhere well enough and when I started sanding it was just coming off on spots so had to respray lightly but it just didn`t look good. It just didn`t want to absorb paint so I can get it look like the other speakers. So, tolex will eventually cover it in the future.

That aside, all went well and tomorrow I have to mount the speaker TRS panel connector, screw the speaker and add some sound absorption. I think less than 30 min work so will post some photos of the ugly creature. Was lucky (the creature) to get some polyurethane coating as this finish didn`t deserve it but had some left over from a previous project...

Last edited by Mario Pankov; 19th October 2019 at 08:35 PM.
  Reply With Quote
Old 19th October 2019, 08:47 PM   #52
29285 is offline 29285  Europe
Account disabled at member's request
 
Join Date: Jan 2010
I can highly recommend "Warnex" paint sold by Thomann. I painted successfully styro foam with that stuff.
  Reply With Quote
Old 20th October 2019, 11:30 AM   #53
krivium is offline krivium  France
diyAudio Member
 
Join Date: Oct 2009

Let's bring the ugly creature to life! Who really care about their look if you are happy with the sound?
  Reply With Quote
Old 20th October 2019, 06:14 PM   #54
Mario Pankov is offline Mario Pankov  Europe
diyAudio Member
 
Join Date: Aug 2007
Location: Sofia
Most guitar cabs designed poorly?
Creature was reanimated today And the sound is...I played for over 2 hours until I noticed how much time has passed. I hate to describe sound especially when I have built it but so far I love it. The bass tightness and the overall sound is exactly what I wanted. Next step would be to dismantle again and paint in plain white.
Attached Images
File Type: jpg 20191019_145823.jpg (669.8 KB, 111 views)
File Type: jpg 20191020_123744.jpg (387.5 KB, 112 views)
File Type: jpg 20191020_125105.jpg (429.7 KB, 110 views)
File Type: jpg 20191020_195929.jpg (423.1 KB, 109 views)
  Reply With Quote
Old 20th October 2019, 06:20 PM   #55
Gnobuddy is offline Gnobuddy  Canada
diyAudio Member
 
Join Date: Mar 2016
Nice looking cab!

Quote:
Originally Posted by Mario Pankov View Post
...bass tightness...
May I ask, what amp are you using to drive your speaker?


-Gnobuddy
  Reply With Quote
Old 20th October 2019, 06:31 PM   #56
Mario Pankov is offline Mario Pankov  Europe
diyAudio Member
 
Join Date: Aug 2007
Location: Sofia
Most guitar cabs designed poorly?
A Laney Ironheart IRT15h - amazing sounding amplifier but has no clean channel which is a bit of disappointing. For rock/metal this thing is absolutely savage.
  Reply With Quote
Old 20th October 2019, 07:45 PM   #57
Galu is offline Galu  Scotland
diyAudio Member
 
Join Date: Apr 2018
Quote:
Originally Posted by Mario Pankov View Post
...so far I love it. The bass tightness and the overall sound is exactly what I wanted.
In the face of some adversity from punters like me, you've persevered and produced a well engineered speaker cabinet - congratulations!

In synergy with the Ironheart it could be ideal for playing death metal with its chugging low riffs!
  Reply With Quote
Old 21st October 2019, 06:49 AM   #58
Gnobuddy is offline Gnobuddy  Canada
diyAudio Member
 
Join Date: Mar 2016
Quote:
Originally Posted by Mario Pankov View Post
A Laney Ironheart IRT15h
Thanks! There are lots of favourable reviews online for that amp.

So it's an all-valve guitar amp with a push-pull pair of EL84 output valves.

A fairly similar amp (except with 6V6 output valves) with no negative feedback was measured (by diyAudio member Printer2) to have an output impedance of roughly 50 ohms.

Those valve guitar amps that do use negative feedback in the power amp section, typically have no more than 6 dB - 10 dB of negative feedback. This would cut the output impedance to roughly half or one-third respectively, say between 25 ohms and 15 ohms.

Another diyAudio member, JohnDH, reported output impedance measurements in the range of 5 ohms to 25 ohms for various (valve) guitar amps. The lower output impedances generally correspond to higher-power amps, using either bigger output valves, or more than one pair of output valves in parallel (4x EL84, etc).

Lacking actual measurements, what follows is merely informed speculation. But we can speculate that the output impedance of the Laney is very likely somewhere between 10 ohms and 50 ohms.

Even the smallest of those values does very dramatic things to speaker Qts (and therefore Qtc.) Ten ohms in series will more than halve the electrical damping in an 8 ohm speaker. In most guitar speakers (with a stiff treated paper surround) Qms is much greater than Qes, and in this case, adding 10 ohms in series will likely roughly double Qts.

This is likely to produce a strong bass hump in the frequency response. I would have expected this to produce strong, but not tight, bass.

Marshall 4x12 sealed cabs are quite popular with some guitarists, and they seen to have the same general behaviour, with a sizeable bass peak in the region of 100 Hz. Again, strong, but not tight, bass.

A boomy bass peak like this is a very bad thing for Hi-Fi. But as many of us have been saying throughout this thread, e-guitar is a very different thing. Clearly, many electric guitar players like having this sort of poorly damped bass peak in the loudspeaker response.

I was unable to find any Thiele-Small parameters for the G12-T75, otherwise I would have at least run a simulated frequency response (with and without an additional 10 ohms - 50 ohms in series).


-Gnobuddy
  Reply With Quote
Old 21st October 2019, 11:39 AM   #59
krivium is offline krivium  France
diyAudio Member
 
Join Date: Oct 2009
Congratulation! So glad for you it turned into something you like.

Have you tried it open back? May sound more 80's early 90's metal.

I am surprised it didn't weight more than particle board, this is good to know.
Plain white cabs, i absolutely love it! If you go tolex something like white snake skin pattern could make it even more savage looking ( if you can assume it!.. but you are a guitarist so it should do!)

More seriously, if you can make some kind of decoupling stand you could gain a bit in tightness ( but probably loose a bit on low end extension). May be worth a try if that is your thing.

I'm interested to know if standing waves are diminished. If you find time make a classical record ( sm57 front close mike) and play different riffs in differents key then try to locate the peaks always presents whatever you play. This is to know if the tactic you used are effective (driver offset and the pyramidal foam). You can speculate the frequency they should appear at using the internal dimension ( i bet you already knew all that but in case of...).

Gnobuddy,
If you have some french basis you can try this link and search for the gt12, you'll find it in the driver database ( the data are for most of them believable from this source as it is a collaborative effort and most come from measurements). Begin a simulation and you'll have the T/S listed as the first info given, up the page.

Catalogue simplifiť haut-parleurs

Last edited by krivium; 21st October 2019 at 11:51 AM.
  Reply With Quote
Old 21st October 2019, 12:51 PM   #60
nigelwright7557 is online now nigelwright7557  United Kingdom
diyAudio Member
 
nigelwright7557's Avatar
 
Join Date: Apr 2008
Location: Carlisle, England
If the guitar cabs were so bad no one would buy them.
Guitar players tend to prefer some "tone" with amps.
They aren't really looking for hi fi. Marshall made a fortune because of that.
__________________
2020 versions of PCBCAD51 and PCBCAD360 out now >>> https://www.murtonpikesystems.co.uk
  Reply With Quote

Reply


Most guitar cabs designed poorly?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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Custom guitar cabs, bargain prices! Anthon Vendor's Bazaar 0 10th February 2017 06:41 PM
HELP!!!! :Bass Guitar Cabs moose54 Instruments and Amps 36 5th August 2009 05:32 PM
Here"s a Simple 14w-32w Guitar amp I designed.... Minion Instruments and Amps 5 15th June 2008 03:51 PM
12" Vintage Guitar Cabs rossco Everything Else 1 17th October 2003 09:23 AM


New To Site? Need Help?

All times are GMT. The time now is 09:06 AM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 14.29%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Copyright ©1999-2019 diyAudio
Wiki