New Posts New Posts RSS Feed - Adventures In Transmission Line Loudspeakers
  FAQ FAQ  Forum Search   Events   Register Register  Login Login

Welcome to the Graham Slee Audio Products Owners Club

 

Open to all owners plus those contemplating the purchase of a Graham Slee audio product wishing to use our loaner program: join here
Subscribe to our newsletter here (Rules on posting can be found here)


Adventures In Transmission Line Loudspeakers

 Post Reply Post Reply Page  <12345 22>
Author
BAK View Drop Down
Senior Member
Senior Member
Avatar

Joined: 14 Mar 2010
Location: Kentucky, USA
Status: Offline
Points: 1601
Post Options Post Options   Thanks (0) Thanks(0)   Quote BAK Quote  Post ReplyReply Direct Link To This Post Posted: 30 Dec 2016 at 11:31pm
Originally posted by Graham Slee Graham Slee wrote:


Here is my idea for a TL for the Alpair 7. I wish I was good at woodwork! (hint)

Graham has the TL terminus (port or TL open end) on the back of the cabinet.
With the exception of the TL terminus location,
  This is very similar to the Radford S.90 as shown here... http://www.t-linespeakers.org/classics/radford.html   ...
     and the Bailey found here...    http://www.mh-audio.nl/bailey_tml.asp  ...


Here is another idea with the port NOT on the front or back...  http://www.mh-audio.nl/TML.asp  ...
 BUT on the TOP ! with only 1 fold in the TL.

The calculators on the mh-audio.nl site I found are good for a very rough approximation only... getting into the "ballpark". Some box size adjustments are still needed here.

HINT:
There may be other calculators that are a closer approximation to Martin J. King's and Dr A.R. Bailey's designs.

There are many speaker designs on the DIY websites... all types.
But, as with many other things, there are also many misdirected ideas as well.

I find the FH3 to have a very strong following and it has been designed with very close approximation to an
accepted design methodology.
(You will find many vague references like the one I just gave in this topic of TLs. Many that have the knowledge
 do not wish to dishonor or violate copyrights of others when making confirming statements. There are so many theories and factual evidences.)

The following is quoted from ... http://www.frugal-horn.com/ ...
"An estimated 1,000+ Frugel-Horn Mk3 have been built by the diy hifi community. FH3 been shown to work with a wide variety of drivers. The FH3 has been followed by a larger Frugel-Horn XL and smaller Frugel-Horn Lite. Independent cottage industry Flat-pak manufacture and bespoke finished Frugel-Horns has started up in Canada (North America), UK, Australia, & The Netherlands. More are being encouraged."

Note that the FH3 is the middle model. The FH XL being larger and the FH Lite being smaller.


Edited by BAK - 31 Dec 2016 at 12:08am
Bruce
AT-14SA, Pickering XV-15, Hana EL, Technics SL-1600MK2, Reflex M or C, Lautus, Majestic DAC, Technics SH-8055 spectrum analyzer, Eminence Beta8A custom cabs; Using Proprius
Enjoy Life your way!
Back to Top
BAK View Drop Down
Senior Member
Senior Member
Avatar

Joined: 14 Mar 2010
Location: Kentucky, USA
Status: Offline
Points: 1601
Post Options Post Options   Thanks (0) Thanks(0)   Quote BAK Quote  Post ReplyReply Direct Link To This Post Posted: 30 Dec 2016 at 11:51pm
Originally posted by BAK BAK wrote:

http://www.t-linespeakers.org/readme1st.html#TL

This site has links to most of the TL design masters.


The above "Read Me First" page was written by:
dave dlugos

Bruce
AT-14SA, Pickering XV-15, Hana EL, Technics SL-1600MK2, Reflex M or C, Lautus, Majestic DAC, Technics SH-8055 spectrum analyzer, Eminence Beta8A custom cabs; Using Proprius
Enjoy Life your way!
Back to Top
BAK View Drop Down
Senior Member
Senior Member
Avatar

Joined: 14 Mar 2010
Location: Kentucky, USA
Status: Offline
Points: 1601
Post Options Post Options   Thanks (0) Thanks(0)   Quote BAK Quote  Post ReplyReply Direct Link To This Post Posted: 30 Dec 2016 at 11:52pm
Originally posted by Drewan77 Drewan77 wrote:

Originally posted by Graham Slee Graham Slee wrote:



Headline: Genesis, Carpet Crawlers blows Graham Slee's socks off Shocked

(or on the LH side floor.... blew his brains out ShockedShockedShocked)

 All that was left is his shoes !!!!
Bruce
AT-14SA, Pickering XV-15, Hana EL, Technics SL-1600MK2, Reflex M or C, Lautus, Majestic DAC, Technics SH-8055 spectrum analyzer, Eminence Beta8A custom cabs; Using Proprius
Enjoy Life your way!
Back to Top
KJFAudio View Drop Down
Senior Member
Senior Member


Joined: 17 Nov 2016
Location: Warwickshire UK
Status: Offline
Points: 119
Post Options Post Options   Thanks (0) Thanks(0)   Quote KJFAudio Quote  Post ReplyReply Direct Link To This Post Posted: 31 Dec 2016 at 8:45am
Originally posted by Richardl60 Richardl60 wrote:

Graham I wish the very best with your TL design I have been a huge fan for over 40 years. They are sadly not very fashionable with commercial manufacturers there are an odd manufacturer in Germany and USA but other than pmc very thin on the ground. Back pressure/loading is important so once you arrive at a working model sure you will find difffering materials and density will impact on the sound quite a lot. Will watch with interest as small TL designs have been virtually non existent (until now).


That Pensil is the only one I haven't actually built! I imagine it compares in a similar fashion to the others. The FHXL goes lower than the Pensil for the 10 series drivers but have a similar character other than that. The way the driver is loaded with air extremely tunable in both speakers with the stuffing. When Scott designed the Pensil range it was a study really in creating a new form factor that made it as easy as possible to build a speaker box with all the benefits normally associated with a TL. My Pensil 11 kits have just been built by a reviewer who thought they were amongst the most transparent speakers he'd had and they do bass aplenty to
UK/EU dealer for Mark Audio Drivers and Manufacturer of speaker kits
Back to Top
Graham Slee View Drop Down
Admin Group
Admin Group
Avatar
Telling it as it is

Joined: 11 Jan 2008
Location: South Yorkshire
Status: Online
Points: 13844
Post Options Post Options   Thanks (0) Thanks(0)   Quote Graham Slee Quote  Post ReplyReply Direct Link To This Post Posted: 31 Dec 2016 at 8:54pm
Having further thoughts about my prototype idea, I think it better to have a removeable side than a removeable baffle. This will mean adjusting the dimensions of the pipe depths to make them uniform because there would no longer be the battens to hold the baffle on. Also I guess the slight taper might be a hindrance to tuning, so it needs to be constant. Hopefully Stefan hasn't started making the boxes...

Some TL designers reckon the Vas has a bearing on the performance and the air mass of the line should be Vas or Vas x 0.7. The volume of the box as it stands is about 2.5 times the driver's Vas.

Making the box smaller would shorten the pipe which needs to be 1.2m (48") to tune to 70 Hz at 1/4 wavelength.

Perhaps the solution would be to stick further thicknesses of MDF on the inside - this would certainly reduce the volume, or maybe the design should be started over?

Here we need the opinion of the specialist (over to you Stefan).


Not simple enough for Google-Bot to understand...
Back to Top
Graham Slee View Drop Down
Admin Group
Admin Group
Avatar
Telling it as it is

Joined: 11 Jan 2008
Location: South Yorkshire
Status: Online
Points: 13844
Post Options Post Options   Thanks (0) Thanks(0)   Quote Graham Slee Quote  Post ReplyReply Direct Link To This Post Posted: 01 Jan 2017 at 3:37am
Having seen so much of the theory being based on actual pipes, and the Alpair 7 fitting a 103mm hole, it occurred to me that 4" (101.6 ID/110mm OD) soil pipe and 92.5º double socket bends could be utilised for practical assessment rather than going to all the trouble making trial and error cabinets.

Were you expecting a LOL at the end of that paragraph?

The seated ear height being approx. 44" (1.1m) would allow for a single downward bend in a 48" overall pipe with the open end down facing. The resulting pipework could be attached behind the baffle of the existing cabinet, which then leads to the question: of what use is the actual baffle (speaker front)? What real acoustic role does it play?

If it plays nothing then the cabinet would then only need to comprise of the pipework, with the speaker stuck in the front, the bottom end of which could be attached to a block of wood acting as a base to stand the contraption on.

Maybe the above is just a daft thought? (my first of 2017 - expecting a humorous answer from Drewan77... Wink)

Not simple enough for Google-Bot to understand...
Back to Top
Graham Slee View Drop Down
Admin Group
Admin Group
Avatar
Telling it as it is

Joined: 11 Jan 2008
Location: South Yorkshire
Status: Online
Points: 13844
Post Options Post Options   Thanks (0) Thanks(0)   Quote Graham Slee Quote  Post ReplyReply Direct Link To This Post Posted: 01 Jan 2017 at 4:21am
Ah, the things you find surfing...

http://audiojudgement.com/speaker-baffle-design-and-diffraction/

Now I understand baffle-step.

Put quite simply the distance between the speaker and the edge of the cabinet will defract at some frequency increasing output above that frequency. In crossover design baffle step compensation is used to combat the increased output. Another way to reduce this boost in output is to cover the baffle with felt...

So here's why the LS35A have a felt surround to the tweeter, and why my hobby felt (see earlier photo) did make an audible difference, and I was not kidding myself.

So, to get minimal upper frequency boost the baffle should be non-existent, and so I am basically making a Teletubbies speaker!

So are the response plots of the Alpair 7 made on a baffle or not? And if so, what was the baffle dimensions? Without such info we are all in the dark.


Not simple enough for Google-Bot to understand...
Back to Top
 Post Reply Post Reply Page  <12345 22>
  Share Topic   

Forum Jump Forum Permissions View Drop Down

Forum Software by Web Wiz Forums® version 12.01
Copyright ©2001-2018 Web Wiz Ltd.

This page was generated in 0.063 seconds.