DIY IPL Acoustics Transmission Line S4tl Speaker Kit Build

[underzone]

Hi all,

after having tried many speakers for my living room and getting mixed results, I have decided to go the DIY route! I have had many sets of speakers over the years from AE109's, Monitor Audio Bronze BX6 (£600) to Linn Majik 140 (£1600) then Monitor Audio Silver 10 (£1500), Kudos Cardea C20 (£2950) till PMC Twenty.24 (£3400). I had decided that I like the low end response and effortless dynamics of the transmission line design, but wanted a model with more bass weight (and finished in Oak to match the floor for WAF). The PMC Twenty.24 is a fine speaker, but in the end the 6.5" bass drive didn't deliver the bass extension and quantity I would expect at that price point.

I had recently been thinking about buying the newly released Proac D20 (£2649) as it features a ribbon tweeter, but was hesitant again that I would likely not get the bass extension with just one bass 6.5" drive. Also the Oak finish I wanted was not an option.

That was when I saw an advert in the back of HiFi News. A company called IPL (http://www.iplacoustics.co.uk/) had a mail order kit for a transmission line kit that featured the renowned Foundtek CD3.0 ribbon tweeter an excellent HiVi Research 8" Kevlar paper bass drive unit and it had a lower frequency response of 23Hz! If you were wondering, the IPL in the IPL Acoustics equation is Ivan Peter Leslie, they are UK based and have been in business for over 20 years. I telephoned IPL and was immediately aware that the owner Ivan wasn't trying to do the usual hard sell. I had initially thought I would order the biggest (and most expensive) kit the S5tl, but Ivan talked me out of it due to my room size and layout. It is not often that a company don't want you to buy their most expensive item. I was also pleased that all my technical questions about the crossover design, boundary distances and tuning methods were competently and easily answered.

I have since ordered the S4tl total kit had it delivered and part built it. This is what I ordered:
http://www.iplacoustics.co.uk/ipl_s4_mk5__transmission_line.htm
The cost delivered was just £595 - amazing value.
The pics below show stage 1, construction. I will add stage 2, finishing & veneering with iron on Oak veneer when I actually do it later this month.

One of the delivered boxes. This one full of machined MDF (the other full of drivers, components and foam):

http://i1278.photobucket.com/albums/y511/pic333TTT/2014-05-15184332_zps56e15881.jpg (http://s1278.photobucket.com/user/pic333TTT/media/2014-05-15184332_zps56e15881.jpg.html)

Starting to build the MDF carcasses. I used Gorilla wood glue and a brad nail gun (optional, I am only using it because I have it) to hold and then clamped the pieces together. The Gorilla wood glue has a clamp time of just 30 minutes so build time was fast:

http://i1278.photobucket.com/albums/y511/pic333TTT/2014-05-16160246_zpsa410dbd6.jpg (http://s1278.photobucket.com/user/pic333TTT/media/2014-05-16160246_zpsa410dbd6.jpg.html)

http://i1278.photobucket.com/albums/y511/pic333TTT/2014-05-16161504_zps1ab5c0ba.jpg (http://s1278.photobucket.com/user/pic333TTT/media/2014-05-16161504_zps1ab5c0ba.jpg.html)

Two cabinets nearly built:

http://i1278.photobucket.com/albums/y511/pic333TTT/2014-05-16214247_zpsb61f832f.jpg (http://s1278.photobucket.com/user/pic333TTT/media/2014-05-16214247_zpsb61f832f.jpg.html)

http://i1278.photobucket.com/albums/y511/pic333TTT/2014-05-16214307_zps49889a44.jpg (http://s1278.photobucket.com/user/pic333TTT/media/2014-05-16214307_zps49889a44.jpg.html)

Acoustic foam now added. Note that there are two 45 degree reflectors that are part of the transmission line. I decided to fill the created voids with Soudal Genius insulation foam to ensure no resonance could occur. I used this foam from ScrewFix with has a stated 60dB acoustic rating. Also I used Evo-Stik carpet spray adhesive as it sticks like crazy (the instructions say to use hot melt glue) and was very easy to use:

http://i1278.photobucket.com/albums/y511/pic333TTT/foam5_zpsc86ade83.jpg (http://s1278.photobucket.com/user/pic333TTT/media/foam5_zpsc86ade83.jpg.html)

Now ready to join the two sides and seal the cabinet enclosure:

http://i1278.photobucket.com/albums/y511/pic333TTT/2014-05-18092953_zps468048ff.jpg (http://s1278.photobucket.com/user/pic333TTT/media/2014-05-18092953_zps468048ff.jpg.html)

One built crossover. The kit design schematics specify a bi-wire crossover. However I wanted a foo free speaker, and modified the design internally to present just one pair of binding posts. I used Pro-G Series Insulated Binding Posts just out of personal preference (the kit comes supplied with 4x gold hard plated posts):

http://i1278.photobucket.com/albums/y511/pic333TTT/2014-05-19134407_zpsf6929a94.jpg (http://s1278.photobucket.com/user/pic333TTT/media/2014-05-19134407_zpsf6929a94.jpg.html)

http://i1278.photobucket.com/albums/y511/pic333TTT/2014-05-19141628_zpsc3c7c051.jpg (http://s1278.photobucket.com/user/pic333TTT/media/2014-05-19141628_zpsc3c7c051.jpg.html)

Crossover installed and wires just waiting patiently. I used Chord Odyssey 2 cable to wire internally, which matches my speakers cable:

http://i1278.photobucket.com/albums/y511/pic333TTT/2014-05-19141547_zps33fd50d1.jpg (http://s1278.photobucket.com/user/pic333TTT/media/2014-05-19141547_zps33fd50d1.jpg.html)

I also made a speaker base plinth (which will be finished satin black) from 2 layers of 15mm MDF glued together. They were later cut to size and a radius was routed on the top edge. This is not supplied by IPL but is something I like the look of:

http://i1278.photobucket.com/albums/y511/pic333TTT/2014-05-27163359_zpsf1e5e65a.jpg (http://s1278.photobucket.com/user/pic333TTT/media/2014-05-27163359_zpsf1e5e65a.jpg.html)

Drivers installed (a small amount of long haired wool goes behind the bass driver (between 10-20g to tune bass extension), speakers placed into position:

http://i1278.photobucket.com/albums/y511/pic333TTT/2014-05-27161942_zps3c77b136.jpg (http://s1278.photobucket.com/user/pic333TTT/media/2014-05-27161942_zps3c77b136.jpg.html)

http://i1278.photobucket.com/albums/y511/pic333TTT/2014-05-27161922_zpsae37a525.jpg (http://s1278.photobucket.com/user/pic333TTT/media/2014-05-27161922_zpsae37a525.jpg.html)

[underzone]

One thing that slightly annoyed me was the Kevlar paper bass driver colour, bright yellow! Unfortunately it seems to be Hi-Vi Research's signature, much like B&W have the pale yellow mid-range drivers. Anyway, bring on the Pentel N50 permanent black marker!

http://i1278.photobucket.com/albums/y511/pic333TTT/pen_zpsa29353bf.jpg (http://s1278.photobucket.com/user/pic333TTT/media/pen_zpsa29353bf.jpg.html)

Two coats/colourings later:

http://i1278.photobucket.com/albums/y511/pic333TTT/2014-05-28180654_zpscc256324.jpg (http://s1278.photobucket.com/user/pic333TTT/media/2014-05-28180654_zpscc256324.jpg.html)

It is an alcohol based permanent dye marker, so the mass added to the Kevlar paper driver is negligible and will not affect sound quality (listening tests confirm this). However I am a lot happier with the look:

http://i1278.photobucket.com/albums/y511/pic333TTT/2014-05-28181204_zps29ce2d41.jpg (http://s1278.photobucket.com/user/pic333TTT/media/2014-05-28181204_zps29ce2d41.jpg.html)

[underzone]

Marking up the oak veneer to cut (with scissors):

http://i1278.photobucket.com/albums/y511/pic333TTT/1_zps6a4379bd.jpg (http://s1278.photobucket.com/user/pic333TTT/media/1_zps6a4379bd.jpg.html)

Using the flush trim router bit to trim excess veneer. I just used the Mrs clothes iron (set to cotton, no steam) to iron it on:

http://i1278.photobucket.com/albums/y511/pic333TTT/2_zps4394aa99.jpg (http://s1278.photobucket.com/user/pic333TTT/media/2_zps4394aa99.jpg.html)

The crossover/speaker terminal cut out. See what a nice job the flush trim bit does!

http://i1278.photobucket.com/albums/y511/pic333TTT/3_zps063ebca5.jpg (http://s1278.photobucket.com/user/pic333TTT/media/3_zps063ebca5.jpg.html)

First coat of Osmo Matt Polyx-Oil going on (same as what is on the oak flooring in my listening room). The speakers will have three coats in all.

http://i1278.photobucket.com/albums/y511/pic333TTT/4_zpsd9cc3a42.jpg (http://s1278.photobucket.com/user/pic333TTT/media/4_zpsd9cc3a42.jpg.html)

Two cabinets just chilling/drying:

http://i1278.photobucket.com/albums/y511/pic333TTT/5_zps858b93fd.jpg (http://s1278.photobucket.com/user/pic333TTT/media/5_zps858b93fd.jpg.html)

Setting up the newly made speaker grilles. I always liked the look of my old Kudos C20 grilles, so I copied them!

http://i1278.photobucket.com/albums/y511/pic333TTT/6_zpsbea07d3b.jpg (http://s1278.photobucket.com/user/pic333TTT/media/6_zpsbea07d3b.jpg.html)

Adding the transmission line vent-hole cover:

http://i1278.photobucket.com/albums/y511/pic333TTT/7_zpsdf71f647.jpg (http://s1278.photobucket.com/user/pic333TTT/media/7_zpsdf71f647.jpg.html)

http://i1278.photobucket.com/albums/y511/pic333TTT/8_zpsb92f4dbd.jpg (http://s1278.photobucket.com/user/pic333TTT/media/8_zpsb92f4dbd.jpg.html)

One done! Just need to chuck the drivers/crossover/wool into the other, and also cover the grilles with the supplied black cloth:

http://i1278.photobucket.com/albums/y511/pic333TTT/9_zps9f4e2a18.jpg (http://s1278.photobucket.com/user/pic333TTT/media/9_zps9f4e2a18.jpg.html)

http://i1278.photobucket.com/albums/y511/pic333TTT/10_zps8963e40e.jpg (http://s1278.photobucket.com/user/pic333TTT/media/10_zps8963e40e.jpg.html)

http://i1278.photobucket.com/albums/y511/pic333TTT/11_zps9caf0434.jpg (http://s1278.photobucket.com/user/pic333TTT/media/11_zps9caf0434.jpg.html)

I always liked the look of my old PMC Twenty.24 base/plinth, so I copied them! Made from two layers of 18mm MDF, sprayed with Halfords cellulose car paint & lacquer. In between the base/plinth and the bottom of the speaker are four M12 nuts painted matt black. The speaker appears to float on top of the base/plinth, like the Neat Elite/Kudos C20 etc:

http://i1278.photobucket.com/albums/y511/pic333TTT/13_zpsfa8038a6.jpg (http://s1278.photobucket.com/user/pic333TTT/media/13_zpsfa8038a6.jpg.html)

http://i1278.photobucket.com/albums/y511/pic333TTT/2ndlast_zps60296c17.jpg (http://s1278.photobucket.com/user/pic333TTT/media/2ndlast_zps60296c17.jpg.html)

Speaker grille cloth now stuck to the frame with hot melt glue:

http://i1278.photobucket.com/albums/y511/pic333TTT/12_zps33ee0873.jpg (http://s1278.photobucket.com/user/pic333TTT/media/12_zps33ee0873.jpg.html)

The oak veneer should darken slightly over the coming months/years and should eventually shade match the floor exactly (I hope). Now to sit back and finally enjoy them!

http://i1278.photobucket.com/albums/y511/pic333TTT/last_zps3e77a626.jpg (http://s1278.photobucket.com/user/pic333TTT/media/last_zps3e77a626.jpg.html)

From start to finish the job took about eight full working days. A lot of work! However the sound quality is sensational and makes it all worthwhile. Listening to Adele’s ‘Rolling In The Deep’ reveals every instrument clearly. The ‘dry’ taught drum beats are reproduced effortlessly as are the vocals when they come in.

Listening to The XX track ‘Fantasy’ shows the brilliant bass extension that transmission line speakers are capable of. The exceeding low notes are easily produced. The room practically shakes yet the notes are clearly defined and melodic.

On another ridiculously bass heavy track, Jessie Wares ‘If You're Never Gonna Move’ you can feel the air pressure from the impressive bass extension and weight, yet the vocals remain clear and not at all congested.

These are easily the best speakers overall that I have owned. I have never has such effortless and controlled bass. The Hi-Vi Research 8” drive has really shocked me. I would also say that the Foundtek CD3.0 tweeter is the second best tweeter that I have heard. The SEAS Crescendo K2 tweeter in the Kudos C20 very narrowly beats this Ribbon, which is to be expected I suppose as it is five times the cost! The Foundtek CD3.0 tweeter is in fact beautifully smooth and not at all harsh, I have no complaints with it at all.

I would happily recommend these IPL speakers to anyone thinking about building some. There is a significant amount of effort/work/patience involved but it is definitely worthwhile!

[awkwardbydesign]

It's very nice, but a bit of a swizz just to paste it over from the Wigwam! A+ for the build, but D for effort (for the post that is). At least I vary my posts between the forums! ;)

[Stratmangler]

Nice build James!
Thanks for sharing.


It's very nice, but a bit of a swizz just to paste it over from the Wigwam! A+ for the build, but D for effort (for the post that is). At least I vary my posts between the forums! ;)

It was first posted over where?
Not everyone goes to the same places you do. I know I don't go over to the Wam - last time I looked at the Wam it was full of keyboard warriors who took delight in sniping at each other more than having constructive discussion.

Your D for effort comment is out of order!

[Barry]

Excellent article James! Well written and with excellent photographs. Well done. Thank you.

(I'm not concerned if it is a 'copy and paste' of an article written by you, and taken from another forum. There is nothing wrong in doing so - I do it myself.)

Good to learn you are enjoying the results of your hard work. :)

[underzone]

Thanks Barry, I thought some people might like the post (those not on the 'other' forums and who haven't seen previously). I personally love build threads with lots of pics and tips!

[Floyddroid]

What a fantastic post. Thanks for sharing. I would love to hear them. Fear not though James. I live miles away.

[RichB]

I don't frequent the wam and enjoyed seeing this post. They look absolutely lovely in your room and whilst I'm sure its not huge consideration for you they look like thy have high WAF as they integrate so well. Not an easy feat for many diy projects.

[awkwardbydesign]

As I said, they are a lovely build.

[Macca]

Outstanding effort, speakers look absolutely amazingly good. Just shows what you can do with a £500 quid kit and a bit of skill and patience. What would a commercial equivalent cost? I'm guessing north of £1500, probably north of 2 grand.

[underzone]

Outstanding effort, speakers look absolutely amazingly good. Just shows what you can do with a £500 quid kit and a bit of skill and patience. What would a commercial equivalent cost? I'm guessing north of £1500, probably north of 2 grand.

I heard on the grapevine that the same ribbon tweeters (with a few more mount holes in the metal fascia) are used in Monitor Audio's PL200 & PL300! And what are they, £5k and £6k?

http://www.madisoundspeakerstore.com/images/products/neocd3.0m-blk.jpg

[Zoidburg]

Amazing Job you done there James, speakers look fantastic!

Im sure they sound awesome as well. I switched to a pair of IPLs last year and love them. I bought mine fully assembled from a guy on the wam paid almost peanuts for them and the blew away my MA RS'8s.

Id seriously consider building a set myself if I ever decided to change but im positive I wouldn't make as good a job of it as you have!

[underzone]

Thanks Zoidburg! My Mrs was calling herself a 'speaker widow' to her mates whilst I was building them... I still need to put gold locking spades (1 large, 1 small) on the woofers and some gold ring connectors for the tweeters. Should take 20mins once I track them down.

[awkwardbydesign]

Thanks Zoidburg! My Mrs was calling herself a 'speaker widow' to her mates whilst I was building them... I still need to put gold locking spades (1 large, 1 small) on the woofers and some gold ring connectors for the tweeters. Should take 20mins once I track them down.
Ah, the 20 minute job. See you in a couple of hours, then. :lol:

[PaulStewart]

Well done James, I'm proud to say I'm banned from the 'wam, for refusing to accept my colleagues being insulted..... Your post is great and it looks like a great job, I love TLs and ribbons so this design ticks a lot of boxes for me and I'd love to hear them. A constructive comment, I have always found TLs work best with very teased out long fibre wool in the line. I prototyped some for a manufacturer about 30 years ago that used the wool in the last third of the line and this may make an improvement by smoothing air in the line, although it should be vibrating not moving :). A very good old test for TL bass performance is to get still air in the room and place a lighted candle near the line opening. Then play a deep pipe organ or better use a tone generator if you have one and see if the flame tremble or blows out. It should tremble, if it blows out you need a little work on the line. :)

Once again thanks for sharing this really interesting read

[awkwardbydesign]

But if it sucks the flame in and sets the wool on fire...........:eek:

[PaulStewart]

But if it sucks the flame in and sets the wool on fire...........:eek:

Then it's time to play that song by the Move....... Get the Fire Brigade :lol:

[hard1175]

A very nice speaker build James if they sound as good as they look your on a win win situation.

[Gordon Steadman]

Terrific looking build and good looking finish.

I was interested to see that the kit comes without rebated drivers. I wonder if that would make any significant difference to the performance?
I must admit that the few pairs I have made without don't seem to appear adversely affected but it always used to be the way to do it.

Congrats.

[awkwardbydesign]

It probably makes the most difference with tweeters. Chamfering the back of the holes may be more important with mid and bass drivers.

[nickjj]

Fantastic build. Really impressed with the finish and veneering you managed to get, and expect they sound pretty awesome. I looked at one of the smaller models earlier in the year but wasn't confident enough in my carpentry skills to go ahead. If you ever decide to sell them I'll be first in the queue!

NB) You've got them close to the wall - are they tolerant of positioning? What would minimum room size for these be do you think? Would a 12w SET amp drive them?

Cheers,

Nick

[underzone]

Fantastic build. Really impressed with the finish and veneering you managed to get, and expect they sound pretty awesome. I looked at one of the smaller models earlier in the year but wasn't confident enough in my carpentry skills to go ahead. If you ever decide to sell them I'll be first in the queue!

NB) You've got them close to the wall - are they tolerant of positioning? What would minimum room size for these be do you think? Would a 12w SET amp drive them?

Cheers,

Nick

I think they sound fine near the rear wall, they are front ported as you can see - my room is quite difficult due to the chimney alcoves but they fit in great. I think they could go up to 20 x 20 ft rooms easily. If you want to send me the SET amp I will let you know :)