Fostex FE206En Rear-Loaded Horn Speakers

Once again Mark tries on the Fostex FE206En high sensitivity fullrange driver, but this time in large rear-loaded horn loudspeaker cabinets. The horn speaker cabinet plans are from the FE206En driver datasheet.

Fostex FE206En Rear-Loaded Horn Speaker Cabinet

Each horn speaker cabinet is made up from thirty-six pieces of 21 mm thick pine plywood.  Australian beeswax is used on the outside of the horn cabinet and heavy cedar oil was applied to the mouth of the horn.

The sensitivity of the FE206En driver is greater than 96 dB / 1W / 1m, so the rear-loaded horn speakers are very well suited for use with very low power tube amplifiers.

Fostex FE206En Back-Loaded Horn Speakers with 6EM7 SET Amplifier

Mark reports very good performance from the back-loaded horn speaker cabinets.

"Where this type of single driver loudspeaker system does shine is in it's ability to image. The back-loaded horn speakers can draw an extremely accurate soundstage. This is due to the fact the all the music is coming from a single point and is not smearing the sound over multiple drivers." 

"Big, bold and made of pine they are. Excellent sounding they are also. For me, with my Paris amplifier (dual mono SE 6EM7 integrated with 4S tube preamp) in triode mode, the combination of a high sensitivity speaker, razor sharp sound stage and extended and very clean mid-range, can lead to a whole new listening experience." 

Full project details are available on the Fostex FE206En Back-Loaded Horn Speaker page.

Cheap Open Baffle Speakers (COBIES)

Bruce has put together a pair of Cheap Open Baffle Speakers - the COBIES.  Relative to most DIY speakers this open baffle project will be quite easy to build.  One of the main design goals for Bruce was to keep the total parts cost under $150US.  The open baffle speaker project was inspired by the "Big Air" open baffle system by Jim Strasser.  

COBIES - Cheap Open Baffle Speakers

Each open baffle uses a GRS 12PF-8 woofer and two Goldwood GT-25 paper cone tweeters.  One tweeter is mounted on the rear of the baffle pointed upwards about 45 degrees.

Rear Mounted Goldwood GT-25 Tweeter

Bruce experimented with various crossover points settling on 3.6 kHz finding that lower crossover points put too much of a demand on the GT-25 tweeters.  Using a calibrated microphone and RTA the in-room response from 100 Hz to 10 kHz was quite smooth and free of any large irregularities. Response below 100 Hz was affected by room nodes but quite good down to 40 Hz.  Above 10 kHz was certainly excellent (up to about 18 kHz).  The overall speaker system sensitivity is estimated at 93 dB / 1 watt at one meter. Bruce uses a pair of 5 watt (each) tube mono block amplifiers (EL84 PP) with the open baffle speakers. 

"The sound is something you will either love or hate. As I said earlier open baffle speaker systems are bi-polar. I really like it, some individuals will not. The speakers have an excellent overall sound. They have a lot of ambiance and provide a good listening experience. Bass is quite clean and robust ..."

Full details are available on the  COBIES (Cheap Open Baffle Speakers) project page.  Comments and questions about this project are welcome in the Open Baffle Speaker Project thread.

DIY Nearfield Monitor Speakers with Fostex FE103En

Fostex FE103En DIY Bass Reflex Bookshelf Speakers

These small computer desktop speakers were built using the in-expensive Fostex FE103En fullrange speaker drivers following the bass reflex enclosure box plans that were provided with the FE103En datasheet.  The enclosure volume is noted as 6 L and tuned to 95 Hz but the the gross volume was calculated to be 6.9 L and the box tuning frequency to be about 97 Hz.  The Fostex FE103En drivers are 100 mm in diameter and have a rated sensitivity of about 89 dB / 1 W / 1 m.  There are a couple of easy modifications that can be made to improve the FE103En drivers which are described in detail on the modifications and tweaks for the small Fostex fullrange speaker drivers information page.  A photograph of the stock Fostex FE103En drivers is shown below.

Fostex FE103En Fullrange Speaker Driver

The speaker cabinets are built from 15 mm thick Baltic birch (11 ply multiplex) plywood.  Acousta-Stuf fiber fill is used inside the speaker enclosure to dampen the rear wave from the driver and to reduce standing waves and internal reflections.  The finished speakers are shown below with the computer.  Since this position the speakers are used in the nearfield, there is no need for a baffle step compensation filter.  The  Fostex FE103En DIY Bass Reflex Bookshelf Speakers project page has full details regarding baffle step compensation for farfield use and pairing the speakers with a subwoofer.

DIY Bass Reflex Monitor Speakers with Fostex FE103En  

These little speakers have bee in use with the desktop computer in the office for a few months now and I am quite pleased with the end results.  With no crossover or filters the speakers deliver wonderful playback full with rich details.  For full project details see the Fostex FE103En DIY Bass Reflex Bookshelf Speakers (Nearfield Monitor) project page.

More Single Driver DIY Speaker Projects

• Zigmahornet Speakers with Fostex FE103E / FE103En
• Fostex FX120 DIY ML-TQWT Speakers
• Fostex FX120 DIY Bass Reflex Bookshelf Speakers
• Fostex FE206En Double Bass-Reflex Speakers

Fostex FE206En Double Bass-Reflex Speakers

Fostex FE206En Double Bass-Reflex Speakers

Fans of low power tube amps love high-sensitivity full-range drivers like the 200 mm Fostex FE206En and with good reason.  The drivers are relatively inexpensive, they sound good and they do not require a crossover.  The main reason for the fan fare is because of their high sensitivity (96 dB / 1 W / 1m), which makes them ideal for use with very low power amplifiers.  However, the high sensitivity and wide frequency bandwidth of the driver come at a cost - a very low mass paper cone and a tiny excursion (Xmax=0.8 mm).  This adds up to mean that extracting bass from the Fostex FE206En is often a challenge.  The common solution to this challenge is a large back-loaded horn type enclosure.

Fostex FE206En Back-Loaded Horn Speaker Enclosures 

The problem is that these elaborate back-loaded horn type enclosures often require a skilled woodworker to construct.  The Fostex FE206En driver datasheet also include a recommended enclosure plan for a suitable bass-reflex type enclosure which is far easier to construct.  Mark has built a couple sets of the Fostex FE206En double bass-reflex speakers and reports that the simple enclosure works well with the FE206En full-range driver.

Fostex FE206En Double Bass-Reflex Speakers 

Since Mark will be using the speakers as part of his home theater setup, undercoating paint was used for a stipple like flat black and non-reflective finish.  Mark reports that the speakers are an excellent mate for use with his 6EM7 SET amp.  Full details are available on the Fostex FE206En Double Bass-Reflex Speaker project page.

More Single Driver DIY Speaker Projects

• Fostex FE103En Bass-Reflex Monitor Speakers
• Zigmahornet Speakers with Fostex FE103E / FE103En
• Fostex FX120 DIY ML-TQWT Speakers
• Fostex FX120 DIY Bass Reflex Bookshelf Speakers

Cello Speakers - Lawrence Audio - CES 2012

CES 2012 doesn't officially kick off until tomorrow, but today I decided to check out the layout of the High-Performance Audio floors at the Venetian.  All the exhibitors were very busy setting up their exhibit rooms and it was nice to chat to them before the large crowds arrive tomorrow.  Secretly my real intent of visiting the show a day before the official start was that I was hoping to get some private listening opportunities.  While walking down one of the hallways the seductive voice of Rebecca Pidgeon pulled me into the Lawrence Audio room who are based out of Taiwan.  Just my luck, their system was ready to play and my private listening session was just moments away.  While it was the voice of Rebbeca that initially caught my attention, I was immediately struck the unique looking speakers on display and the wonderful sound emanating from them.

Lawrence Audio Cello and Violin Speakers at CES 2012

In the photo above are the new Cello speakers (larger, inside) and the Violin speakers (smaller, outside).  The Violin ($7500US) speakers won an Innovations award at CES last year and this year the Cello ($20,000) speaker have received an Innovations award this year.  The unique looking speakers resemble the instrument that they are named after which really is a refreshing change from typical boxy speaker designs.  The Cello speakers each use five drivers to make a 3.5-way floor standing loudspeaker.  The loudspeaker employs an air motion tweeter and an air motion mid-treble.  The woofer and subwoofer units are 8-inch aluminum framed drivers with a non-woven carbon fiber cone.  There is also a rear firing ribbon tweeter which I quickly identified as an Aurum Cantis G2Si.  The crossover frequencies are set at 700Hz, 1.7kHz, 2.6kHz and 9kHz with preimum crossover components used throughout.  The speakers have a nominal impedance of 4 ohms (3.2 ohms minimum) with a frequency response noted as 32Hz to 40kHz and a sensitivity of 90dB.  The loudspeaker enclosures are vented at the bottom.  Shown below with the Cello speaker is Lawrence Liao who is the acoustic designer and founder of Lawrence Audio.

Lawrence Liao of Lawrence Audio with Cello Speakers

The private listening session with Rebbeca Pidgeon and the Cello speakers was wonderful.  I am very familiar The Raven recording and the Cello speakers did a fabulous job reproducing this excellent Rebbeca Pidgeon recording.  The Cello speakers produced a very wide and deep soundstage.  Most impressive was the focus and the deep bass.  With closed eyes one can distinctly pick out all the instruments in the recording.  With it's unique looks and excellent sound reproduction, I'm sure many will be wrting about these speakers at CES 2012.    For more information see the Cello Loudspeaker at Lawrence Audio. 


More CES 2012 Show Coverage

• 2012 CES, Las Vegas - diyAudioProjects.com Show Coverage thread

Knock-Down Birch Speaker Cabinets

Speaker building is a lot of fun and there are many who would love to try it out but can't due to some common woodworking hurdles.  You may not have the space, tools or skills necessary to build a good loudspeaker enclosure.  For others sawdust or climate (winter) could be the problem.  Fortunately there are some great solutions that can eliminate much of the woodworking necessary to build a speaker box.  For a number of years Dayton Audio has been producing pre-made speaker enclosures like the Dayton pre-made curved speaker cabinets which make it real simple to put together a great looking finished speaker.  Perhaps the only downside to the great looking ready-made cabinets is that they eliminate too much DIY and they are bulky to ship.

Enter these great Knock-Down Birch Cabinets from Parts Express.  The cabinets are CNC-cut and made from seven-ply, 1/2" birch panels.  The cabinets have dadoed top, bottom, sides and braces to maximize the gluing surface.  The knock-down speaker cabinets are unfinished leaving you with many different finishing options.

Knock-Down Birch Speaker Cabinets

Shown in the photo above is the Knock-Down Birch 5.1 Home Theater Cabinet Package and a Knock-Down Birch 0.60 cu ft Monitor Cabinet.  The YouTube video below shows just how simple it is to put together the knock-down birch speaker cabinets.

With the CNC birch knock-down cabinets it is easy even for the beginner to end up with amazing finished results without the need for expensive tools or access to a woodshop.  There are a number of cabinet sizes to choose from.  See the Knock-Down Birch Cabinets for a full selection.

More DIY speaker kits and cabinets

• Dayton Pre-made Curved Speaker Cabinets
• BK-12m Folded Horn Kit - Fostex FE126En 
• Tang Band D4-1 DIY Horn Speaker Kit

BK-12m Folded Horn Kit - Fostex FE126En

There is a new high-sensitivity folded horn speaker kit being offered by Madisound.  The new BK-12m is a single-driver folded horn speaker kit that follows in the lineage of the BK-16 and BK-20 designs.  The BK-12m uses the Fostex FE126En full-range speaker driver in a custom folded horn enclosure while the driver is run full range with no filters whatsoever.  The Fostex FE126En driver is 4.7" (120 mm) in diameter with a rated sensitivity of 93dB/W(m).  This high-sensitivity means that the BK-12m speakers will be suitable for use with low powered amplifiers.

BK-12m Folded Horn Kit - Fostex FE126En

The enclosure panels are made using high quality 5/8" (16 mm) thick Baltic Birch multiplex cut using a CNC machine and bundled as a flat pack.  Once completed the speaker cabinets have overall dimensions of 31-5/8" x 7-1/4” x 14-1/2" (800 x 185 x 370 mm).  The Birch plywood is unfinished so you can finish the speakers how you like.

The BK-12m speaker kit includes:

• 2 x Fostex FE126En 4.5" Full Range Drivers;
• 2 x Unassembled, unfinished Baltic Birch Cabinets;
• 3 oz. Acousta-Stuff internal damping material;
• 5 ft Supra Classic 1.6 15 AWG speaker wire;
• 4 x QC187 Quick Connects (2 red, 2 black);
• 8 x 8X1 Socket Head Wood Screws (8x Philips Head wood screws also included);
• Assembly Instructions.

To put the kit together you will need just a screwdriver, wood glue, sand paper, bar clamps and binding posts.  An inside view of the folded horn speaker enclosure is shown in the photo below.

 

Inside - BK-12m Horn Speaker Kit - Fostex FE126En

 The BK-12m kit is available from Madisound for $315US + shipping.  For full details about the BK-12m speaker kit see the product page at Madisound.

More single-driver speaker kits and projects:

• Tang Band D4-1 DIY Back Horn Speaker Kit
• Fostex FX120 ML-TQWT Speaker Project 
• Fostex FX120 Bass Reflex Bookshelf Speakers

DIY 2-Way Tower Speakers - Ion

Adam has put together a fantastic looking pair of tower loudspeakers and he has shared his design with us.  The speaker design uses a Tang Band 25-1372SC 1" inverted titanium dome tweeter combined with a pair of Audax HM170CO 6" woven carbon fiber mid-woofers and used in a TMM configuration.

The loudspeaker enclosures are constructed using 1.5" thick MDF with solid oak side panels. The overall dimensions of the tower speakers are 37.5" x 8.5" x 11.5" with each weighing about 60 pounds.  The MDF is painted with a textured graphite spray and the side oak panels are stained.

Speaker Box Assembly with Straps

Test Fitting the Drivers

A 2-Way passive crossover dividing network consisting of a 3rd order Butterworth filter at 4000 Hz is used along with an impedance correction network.  The nominal impedance of the speakers is noted at 4 ohms and the loudspeaker covers a frequency range of about 60 Hz to 20 kHz.  In-room you will get some additional bass extension (shown on the in-room measurements).  The total cost for the pair of tower loudspeakers was about $900 US.

Adam reports that the Ion speaker build is his favorite so far.  "The Audax HM170CO woofers produce very warm natural tones up through the upper midrange. With the TangBand 25-1372SC tweeter the highs are crystal clear, detailed but far from harsh.  The Ion speaker is a very challenging build but it comes with a huge payoff! These have quickly become my favorite loudspeakers."  Great work Adam and thanks for sharing your work.

For the full details of Adam's speaker project see the Ion - DIY 2-Way TMM Tower Loudspeaker Project page.

More DIY Speaker Projects by Adam

• HiVi SP10 DIY Subwoofer Project
• 1.618 HiVi 3-way DIY Tower Loudspeakers 
• 1.618 HiVi DIY Center Channel Speaker

Feastrex NF-5 and NF-5ex Drivers at SSI 2011

We are big fans of single full-range driver loud speakers so we were excited to check out the Feastrex drivers. Michael Tang of Mike Tang Audio is importing the Japanese Feastrex NF-5 and NF-5EX drivers into Canada and had them on display at the show.

The 5" Feastrex NF-5 ($2000CDN, shown above) uses a large Alnico magnet.  The handmade cones are made from Japanese Washi paper (a higher density fibrous paper) which is impressed in a spiral pattern with embossed ridges.  The drivers surround is made from lamb skin.

The 5" Feastrex NF-5ex ($3000CDN, shown above) uses the same Washi paper cone and a lambskin surround, but with a motor that uses a field-coil magnet (electromagnet).  The field-coil magnet can be operated between 10 and 17V dc.  Changing the voltage allows you to change the damping of the driver.  Michael uses a 12V car battery for the field-coil magnet.  16 ohms, 95 dB, 35 to 25,000 Hz (+/- 3dB).

A Mastersound Compact 845 SET powered the 5" Feastrex NF-5 drivers which were housed in a bass reflex enclosure (enclosure plans from Feastrex, shown below), no passive filters were used.  The speakers sounded excellent, wide soundstage and impressive depth.  The single drivers delivered superb clarity with vocals to die for. 

 

Michael indicated that he is working on a transmission line enclosure design for use with the Feastrex NF-5 and NF-5ex drivers which he plans to have ready for the TAVES (Toronto Audio and Video Entertainment Show) this fall.

More Salon Son & Image 2011 Coverage

• Orangutan O/96 High Sensitivity Speakers
• Little Horn Speakers by Specimen Products
• New Solen.ca DIY Speaker Kit
• AuDIYo.com room (Dynaco ST70 upgrades)
• Voxativ Ampeggio Rear Loaded Horn Speakers 
• Salon Son & Image 2011 - diyAudioProjects.com Show Coverage thread

Solen.ca DIY Speaker Kit - SSI 2011

On display on the Solen.ca room was a new DIY bookshelf speaker kit that is currently being developed and should be available soon.

 

The DIY speaker kit will use a pre-finished curved Dayton Audio 0.38 ft^3 speaker enclosure.  The drivers are from Airborne, a 120 mm wood cone driver with a 25 mm voice coil (HR124B8-10L) and the high-end is covered by a Air Motion Ribbon Tweeter (RT-20021).  The kit will use a 2-way passive crossover which has yet to be finalized.  No word on when exactly the DIY speaker kit will be available but Solen indicated that that the price of the kit will be about $550.  As more details come available about the kit we will post an update.

Also on display were a number of drivers, amplifiers, connectors and feet for you DIY speakr projects.

  

More Salon Son & Image 2011 Coverage

• Orangutan O/96 High Sensitivity Speakers
• Little Horn Speakers by Specimen Products
• AuDIYo.com room (Dynaco ST70 upgrades) 
• Voxativ Ampeggio Rear Loaded Horn Speakers 
• Feastrex NF-5 and NF-5ex Fullrange Drivers 
• Salon Son & Image 2011 - diyAudioProjects.com Show Coverage thread

New Fullrange Drivers by Tang Band Speakers

Tang Band Speakers has announced four new fullrange speaker drivers which will be added to their growing lineup of drivers.  The new paper fullrange drivers are sized at 3" ,4" ,5"  and 6".  The drivers appear very similar to the 8" Tang Band W8-1772B and W8-1808B fullrange drivers in that they all feature a die cast frame an underhung motor design with a multiple-element neodymium magnet system.  Instead of a cloth half-roll surround the new drivers use a rubber surround.  The Xmax of the fullrange drivers is a healthy 4mm for the 3" unit and 5mm for the 4", 5" and 6" drivers.  A unique looking phase plug is used to prevent phase cancellations and improve high frequency extension and dispersion.

Tang Band W3-1878 Fullrange Driver

Nominal Impedance 8 ohms, DCR 6.5 ohms
Sensitivity 1W/1m, 88 dB
Frequency Response, 75-20kHz
Free Air Resonance, 75 Hz
Rated Power, 12 W
Maximum Power, 25 W
Qts, 0.28 
W3-1878 datasheet.

Tang Band W4-1879 Fullrange Driver

Nominal Impedance 8 ohms, DCR 6.3 ohms
Sensitivity 1W/1m, 87 dB
Frequency Response, 55-20kHz
Free Air Resonance, 55 Hz
Rated Power, 25 W
Maximum Power, 50 W
Qts, 0.43

W4-1879 datasheet.

Tang Band W5-1880 Fullrange Driver Nominal Impedance 8 ohms, DCR 6.3 ohms
Sensitivity 1W/1m, 88 dB
Frequency Response, 45-20kHz
Free Air Resonance, 45 Hz
Rated Power, 30 W
Maximum Power, 60 W
Qts, 0.32

W5-1880 datasheet. 

Tang Band W6-1916 Fullrange Driver

Nominal Impedance 8 ohms, DCR 6.8 ohms
Sensitivity 1W/1m, 91 dB
Frequency Response, 60-20kHz
Free Air Resonance, 60 Hz
Rated Power, 30 W
Maximum Power, 60 W
Qts, 0.46

W6-1916 datasheet. 


There is no indication on pricing or when the drivers will be available.

Similar Posts:

• Tang Band D4-1 DIY Back Horn Speaker Kit

What's Playing: Roy Orbison - All-Time Greatest Hits (MFSL - Gold)

DIY HiVi Research Swans M1 Speakers

We got an email from Daniel Bolduc (Quebec, Canada) letting us know that he has followed up his DIY Swans Tempus Bookshelf Speakers with another DIY build of a HiVi Research speaker.  Daniel tells us that the speakers were built for his uncle who was very impressed with the Tempus speakers, but wanted something a little smaller and finished in a piano black high gloss finish.

HiVi Swans M1 Speakers

Sticking with drivers from HiVi, Daniel proposed to build a DIY version of the Swans M1 Speakers. For the enclosure Daniel used a pair of ready made speaker enclosure from Parts Express.  I used a pair of the curved Dayton Audio 0.38 ft^3 enclosures with black piano gloss finish for my Fostex FX120 bookshelf speakers and the enclosures are well built and look great.

Dayton Audio 0.38 ft^3 Prefabricated Speaker Enclosures

The high gloss finish on the speaker cabinets will scratch easily so be sure to cover the area well so you don't scratch it with the router when cutting the port and driver holes.  The crossover schematic is shown below and Daniel wound his own inductors for the crossover.

HiVi Swans M1 Crossover Schematic

Hand Wound Air Core Inductors for Crossover

The drivers used in Swans M1 speakers are the HiVi F5 (5" bass / midrange) and the HiVi RT1C planer tweeter.

Mounted Crossover Circuits

The speaker project cost about $550CDN for the pair and Daniel estimates he invested about 55 hours.  I think Daniels build looks much better than the original Swans M1 speakers. 

Finished DIY HiVi Swans M1 Speakers

Daniel writes: "So far, I'm very satisfied with the M1's and my uncle is rediscovering his discography with the pair I built for him and is also impressed by the sound reproduction quality."

For full details, more photographs and a materials list for this DIY speaker project, see Daniel's Swans M1 speaker build. 

Related DIY HiVi Speaker Projects:

• HiVi Swans Tempus Bookshelf Speakers
• HiVi Center Channel Speaker
• HiVi SP10 Subwoofer Project 
• HiVi 3-Way Tower Speaker Project

What's Playing: Steely Dan - Pretzel Logic

Tang Band D4-1 DIY Rear Horn Speaker Kit

This winter I wanted to build another set of speakers but there were a couple of problems. My woodworking skills are not great and I don't have a heated workshop where I could work as sawdust and paint fumes are typically not welcome in the home. With that in mind I was looking for a speaker that required not cutting or finishing and came across the Tang Band D4-1 DIY Back-Loaded Horn Speaker Kit.


The kits as supplied is 100% ready to build with all the necessary parts and tools required except for a soldering iron. There is no cutting required and the small speaker kit goes together just like the ready-to-assemble furniture that you would find at Ikea. The enclosure just stacks up and is held together with hex screws. The enclosure is a rear-loaded expanding horn which houses a single fullrange driver, the Tang Band W4-1617.


The enclosure was very simple to put together and the exterior wood face came pre-finished with a low gloss finish. The finish looks like it it can be lightly sanded and painted should one desire a different finish. The overall dimensions of each enclosure is 162 mm x 320 mm x 500 mm (W x H x D) and the finished speakers weigh 10.9 kg each.

The net result is a simple, attractive and compact back horn speaker that sounds great and is fun to build!

For full details see the Tang Band D4-1 DIY Back-Loaded Horn Speaker Kit review.

What's Playing: The Traveling Wilburys - Last Night

Simple DIY Monitor Speakers

We recently received an email asking for some clarification about the difference between line-level and speaker-level Baffle Step Correction Circuits with a reference to the DIY S.E.Xy Speaker Project over at Bottlehead.com. This message brought our attention to a very simple speaker project that we thought we would point out to our readers. A photograph of the S.E.Xy Speaker Project is shown below.


In short, the small sealed monitor speakers are comprised of inexpensive Fostex FE166E fullrange drivers and housed in prefabricated Dayton Audio 0.25 ft^3 cabinets from Parts Express. This is a very simple speaker project and the only woodworking required is a couple of holes through the front baffles for the drivers (electric drill and a hole saw should do).

What caught my attention with this project was the fact that the 6.5" Fostex drivers actually fit in the small prefabricated speaker cabinets. While I have used the great looking Dayton Audio speaker cabinets in the past, I never bothered to check if the 6.5" Fostex drivers would fit.

Fostex FE166E vs FE167E
Of course some of you may prefer to use the Fostex FE167E fullrange speaker driver in place of the FE166E and that should not pose any issues. The FE167E has the same efficiency of 94dB but with it's higher Qts it will be able to produce more bottom-end which will allow you to lower the crossover point and possibly even allow you to get away with just one subwoofer. The figure below shows the modelled frequency response of the two drivers in a 0.25 ft^3 sealed enclosure.


The modelled response shown above uses the T/S Parameters noted on the Fostex data sheets. However, based on our experience with measured T/S Parameters from other Fostex drivers, expect Qts to be a little larger than noted on the data sheet. This means that we can expect a little more bass than what is shown on the plot. In addition to getting more bass out of the FE167E, you may also prefer it as it does not exhibit the rising frequency response of the FE166E which some may find too shouty.

Baffle Step Compensation: Line-level vs Speaker-level
This speaker project was meant for use with the 2W Bottlehead Single Ended eXperimenter's amplifier and therefore Line-level Baffle Step Compensation is the most practical choice as it won't waste the precious power of small tube amps. If power is not a concern, you can use the Baffle Step Circuit Calculator to come up with suitable speaker-level circuit.

For those wondering about the line-level BSC I have run a couple of simulations. I did not know the input impedance of the Single Ended eXperimenter's tube amp so I assumed 100k-ohms.



It would be a good idea to try the BSC on a protoboard and adjust the values to suit your room and personal taste. I would start without the 1.2nF (0.0012uF) capacitor, especially with the FE166E.

The inexpensive Fostex drivers work well in sealed enclosures. I am still very happy with my Sealed Fostex FE127E Bipole Speakers. For those of you afraid of woodworking, the prefabricated Dayton Audio cabinets are for you. Also, for the time being PartsExpress is offering free shipping on most orders over $98 (limited to USA).



More DIY Bookshelf Speaker Projects:

• Fostex FX120 DIY Bass Reflex Bookshelf Speakers
  
• Fostex FE127E DIY Bass Reflex Bookshelf Speakers
• Fostex FE167E DIY Bass Reflex Bookshelf Speakers
  

What's Playing: Emilie Mover - That Song

Seas Drivers and Granite Loudspeaker Box

I've seen some pretty sharp looking diy speaker projects on the net, but these guys take the cake.


The enclosure for these great looking and unique speakers is made out of 20 mm thick black granite. Yup, granite. Once finished, each loudspeaker checks in at about 35 kg so you don't want to drop these. The speakers were put together by Radoslav and his friends in Slovakia. The speaker enclosure is a 15L bass reflex design that is tuned to 45 Hz through a rear firing port. The drivers were sourced from Seas and consist of a G17REX/P woofer and 27 TFFC tweeter. The dividing network is second order at 2500 Hz.


The measured frequency response is very flat and shows surprising low end response despite that enclosure size is relatively small size. Radoslav reports that the finished speakers sound and look great.


See the DIY Granite Speaker project page for full details. Obviously there are very few of you that will have the resources to replicate this project, but it is nice to look at and there is no reason why it should work well using more practical enclosure material like wood.

What's Playing: Diana Krall - 'S Wonderful

Fostex FE167E Bass Reflex Speakers

by Mark Houston


The very first pair of speakers I put together some thirty-eight years ago was a pair of single-driver loudspeakers using 8” Kaltro twin cone drivers. As I type this, I find myself once again listening to speakers using a single full-range driver. This time it is the 6.5” Fostex FE167E fullrange driver. I had recently completed a small low wattage 6T9 valve amplifier, and asked Gio for some suggestions on speakers to match the amp. He suggested the Fostex FE167E. When I saw they were 94dB efficient I ordered them instantly. Packaged with the drivers were two enclosure plans - a floor-standing unit as well as a bookshelf enclosure. I opted for the smaller bookshelf speaker box. The Fostex Recommended Standard Bass Reflex Type Enclosure is 15L with a 50 by 50 mm port that can exit from the front or rear. The enclosure plan is shown below.


The speaker boxes were put together by a neighbor using 18 mm MDF. The boxes were clamped during the gluing process and the inside joints were sealed with additional glue. The back panel had heavy speaker sound absorbing vinyl glued over its surface and the box was lined with a single layer of thick Dacron (tontine).


The binding post block was fitted and oxygen free copper speaker wire was used for the connections. Sealing sticky back foam was placed under the connecting block and also under the drivers which were screwed in place. The boxes were pre-sprayed with paint. Later grills were added by cutting the center out of a piece of MDF, stretching and stapling speaker cloth over the frames. The grills were attached to the speakers using Velcro.


The baffle step correction / compensation (BSC) calculator can be used to determine a BSC specific to the width of your baffle. The amount of attenuation required will be subject to your listening room and amplifier as well as personal taste. Typically about 4 to 6 dB of attenuation is good. You can experiment with the component values shown below and select a BSC to suit your room, amplifier and personal preference. I am using L=1mH and R=2.7ohms.


Out of the box the first thing you notice about the speaker drivers are the ultra-light the cones and very stiff suspension. The first few days of playing will see the drivers settle though expect to put in twenty to fifty hours before they settle completely. If you are not use to listening to single-driver loudspeakers you may be a little shocked at first. I was, but it doesn’t take long to recognize the all the good qualities of a single-driver speaker system. At a recent Melbourne Audio Club night held at my residence the Fostex FE167E speakers were auditioned with a small 6T9 tube amplifier and they received many accolades from the very discerning listeners. When compared with small 2-way bookshelf speakers the Fostex FE167E produced more bass and equal treble response. Most members could not choose one pair of speakers over the other. Voices however do appear forward on strong vocal tracks. This is not unpleasant just obvious.


When teamed with the 6T9 tube amp, for which they were intended, they really come into their own. They are LOUD with only a few watts driving them, produce good bass and excellent mids and highs. The Fostex recommended enclosure design works well with the drivers and produces some excellent violin and cello gritty earthy notes in the instrument's resonance and character. Piano sounds soft, rounded and musical. Voices tend to come forward a little of the rest of the instruments as do some upper-middle frequencies. This adds some extra dimension to your listening.


Update: 4 May 2009
The plot below shows the measured near field response of the speaker system. The upper line on the plot is the measured response with no filters in place. The lower green line is the response with a baffle step compensation circuit of about 3dB.


See the Fostex FE167E Fullrange Driver page for more information and enclosure ideas for this driver.

More DIY Bookshelf Speaker Projects:

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• Fostex FE127E DIY Bass Reflex Bookshelf Speakers
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