Alpair 12P Gen. 2 (paper cone) - Page 2 - diyAudio
Go Back   Home > Forums > Commercial Sector > Manufacturers > Markaudio

Markaudio Designers and builders of audiophile grade drivers

Reply
 
Thread Tools Search this Thread
Old 8th April 2012, 04:36 AM   #11
diyAudio Member
 
markaudio's Avatar
 
Join Date: Nov 2008
Thanks MP9, guys,

I must confess to being a bit nervous. This 12P cone is very sensitive. I personally fell in love with it, but it will be a demanding driver. It took an hour just to get them to relax enough to make the listening experience viable. I remember a similar situation with the 6P. Scottmoose (I think Dave also) ran prototype 6P's over 100 hours before they sweetened.

I'm feeling edgy because the 12P's higher SPL and the soft suspension compliance makes them really dynamic. These paper cones are more robust than the Gen. 1 metal, but to get the best from them, box, designs, amps and source will need to be good. Driven hard, they won't sound nice. Driven correctly, they'll make your hairs stand on end. Berlioz 2nd movement was absolutely electric.

I'll do my best to publish the the data set later today.

Cheers
Mark.
  Reply With Quote
Old 8th April 2012, 08:59 AM   #12
diyAudio Member
 
markaudio's Avatar
 
Join Date: Nov 2008
Hi Guys,
Here's the data for from the latest anechoic test:

Alpair 12P: mass production cone,06-Apr 2012 - LMS V4
Revc= 7.000 Ohm
Fo= 40.641 Hz
Sd= 147.411 cm
Vas= 46.421 Ltr
Cms= 1.504m M/N
Mmd= 9.155m Kg
Mms= 10.184 g
BL= 7.618 TM
Qms= 1.854
Qes= 0.314
Qts= 0.268
Levc= 51.731u H
No= 0.961 %
SPLo= 91.878 dB

I think this is about as good as I can get it. I was hoping to keep the Mms under 10g but to do that, I'd have to remove the final pass stiffening process, not wise on a cone this size.

Re the frequency, this latest RAW data graph it pretty much the best I can get. Its going allot higher and has more SPL than the Gen. 1 metal driver. The oscillatory transition comes in quite low on this driver @ around 500-Hz. Thats quite nicely positioned being low in the telephonic band (Telephonic = 400Hz to 4-kHz), although for some may be a little audible given the lively resonant characteristic of this cone. We didn't detect any anomaly during the first listening session. A reminder this is RAW data so lets hope I'm not punished for being transparent. As some of you know, other published data is often smoothed.

The impedance is well controlled, better than I expected for a CCAW coil. Should be well suited to 2a3, 6L6, 300B etc. etc. valve (tube) lovers and could be interesting for the new lower powered class D and T's.

Cheers

Mark.
Attached Images
File Type: jpg Alp12P-fr-april-2102.jpg (117.2 KB, 1120 views)
File Type: jpg Alp12P-Imp-april2012.jpg (131.4 KB, 922 views)

Last edited by markaudio; 8th April 2012 at 09:05 AM.
  Reply With Quote
Old 8th April 2012, 09:38 AM   #13
frugal-phile(tm)
diyAudio Moderator
 
planet10's Avatar
 
Join Date: Oct 2001
Location: Victoria, BC, NA, Sol III
Blog Entries: 5
Alignment wise, it looks like this parameters give ths same or similar challenges as the previous gen. I will prep & post some sims tomorrow. Alpair 10.2 and EL70 are still going to be the bass champs.

I might be able to use a bit more, but not much more than the current miniOnken

dave
__________________
community sites t-linespeakers.org, frugal-horn.com, frugal-phile.com ........ commercial site planet10-HiFi
p10-hifi forum here at diyA
  Reply With Quote
Old 8th April 2012, 10:06 AM   #14
diyAudio Member
 
simon dart's Avatar
 
Join Date: Mar 2004
Location: Herefordshire
Hi Mark,

Looking good! Did the TPR moulded arrestor to brake limit the power-train's travel make it in to the design?
__________________
Bill Bryson: It is no longer permitted to be stupid and slow. You must choose one or the other.
  Reply With Quote
Old 8th April 2012, 10:03 PM   #15
diyAudio Member
 
markaudio's Avatar
 
Join Date: Nov 2008
Quote:
Originally Posted by simon dart View Post
Hi Mark,
Looking good! Did the TPR moulded arrestor to brake limit the power-train's travel make it in to the design?
Hi Simon,
Good to hear from you. I'm still working on the arrestor design. Its shouldn't be needed on the Alp12P as the cones are a bit more robust. The 12P will be likely deafen the listeners ears before it reaches a critical load.

I'm looking to make the arrestor for smaller drivers as they are more vulnerable.

Cheers
Mark.
  Reply With Quote
Old 8th April 2012, 10:38 PM   #16
diyAudio Member
 
markaudio's Avatar
 
Join Date: Nov 2008
Default Using existing Pensil 12 cabs + new boxes

Hi Guys,
I've received several messages asking me if the existing Pensil 12 box can be used for the 12P. I've chatted to Scott, he tells me its OK but the alignment is not optimal. The thinking is to reduce the internal damping material by some 15%. Like me, you'll need to experiment with the damping.

We played the 12P's in Pensil 12's last Friday and got promising results.

For those who want to build dedicated new Pensils for the 12P, my thanks in advance to Dave as I hope he's volunteered to draw the bigger box. More details on this later.

For those guys wanting to make a smaller simple box (vented), around 17 to 19 litres is looking the most likely option at this stage. The vent tuning should work out at around 50 to 55Hz. More on this later.

I think Dave will also post some sims.

Thanks
Mark.
  Reply With Quote
Old 8th April 2012, 10:50 PM   #17
diyAudio Member
 
markaudio's Avatar
 
Join Date: Nov 2008
Default Power handling for 12P

Hi guys,
Several messages on this issue, the 12P won't need much power as its 92dB + compliant suspensions. I'll be doing more testing throughout the week but likely rate as follows:

1- Power handling = 30 watt Nom. (60 peak)
2 - Excursion should not exceed 6-mm 1 way.

Re recommended amps, already mentioned in earlier posts. This is a driver for low power set-ups. So far, 3.5 watts (Miniwatt N3) is fine with no evidence of clipping. But check your set-up for clipping if using a flee amp.

Cheers
Mark.
  Reply With Quote
Old 9th April 2012, 01:20 AM   #18
frugal-phile(tm)
diyAudio Moderator
 
planet10's Avatar
 
Join Date: Oct 2001
Location: Victoria, BC, NA, Sol III
Blog Entries: 5
Quote:
Originally Posted by markaudio View Post
Hi Guys,
I've received several messages asking me if the existing Pensil 12 box can be used for the 12P. I've chatted to Scott, he tells me its OK but the alignment is not optimal. The thinking is to reduce the internal damping material by some 15%. Like me, you'll need to experiment with the damping.
Scott has sent me data for the optimized Pensil12.2P -- it is only a minor change from existing, so given an MLTL's high tolerance to variablily of drivers, playing with damping should give a fine box. SuperPensil users should have less work (my guess).

dave
__________________
community sites t-linespeakers.org, frugal-horn.com, frugal-phile.com ........ commercial site planet10-HiFi
p10-hifi forum here at diyA
  Reply With Quote
Old 9th April 2012, 01:58 AM   #19
frugal-phile(tm)
diyAudio Moderator
 
planet10's Avatar
 
Join Date: Oct 2001
Location: Victoria, BC, NA, Sol III
Blog Entries: 5
Quote:
Originally Posted by markaudio View Post
I think Dave will also post some sims.
Sealed, and an example reflex. With vented the largest i was willing to go was 16 litre, althou if you want a box with a droppy LF you can go larger and tune low and still not violate the multiple zero crossing of the 1st derivative rule i use.

dave
Attached Images
File Type: gif Alpair122p-proto-sealed-sim.gif (28.9 KB, 869 views)
File Type: gif Alpair122p-proto-exampleBR-.gif (26.4 KB, 841 views)
__________________
community sites t-linespeakers.org, frugal-horn.com, frugal-phile.com ........ commercial site planet10-HiFi
p10-hifi forum here at diyA
  Reply With Quote
Old 9th April 2012, 02:29 AM   #20
diyAudio Member
 
Join Date: Oct 2005
Would it be possible to see a "waterfall" diagram? The original 12 wasn't too great in that respect (according to a German test I once saw), I do have high hopes for this new version.
Frequency plots at 15 and 30 degrees off center would also be interesting.
  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
Alpair 6P Gen. 2 (paper) introduction markaudio Markaudio 30 21st August 2013 03:59 AM
Next Gen 70-mm Markaudio paper cone markaudio Markaudio 24 5th April 2012 10:59 PM
Paper cone tweeters for paper cone mids? dabbler Multi-Way 31 20th March 2012 12:25 PM
Alpair 6 Gen 1 wushuliu Swap Meet 0 16th February 2012 01:54 AM
Alpair 6 - Gen 2. - Prototype 1 markaudio Markaudio 53 11th November 2010 04:18 AM


New To Site? Need Help?

All times are GMT. The time now is 09:57 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