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Thanks so much for the video Dave! I'd love to answer a few of your questions: The tweeter is made by Tymphany. I assembled the PCB by hand and the bodge wire was to adjust grounding. The final version will not have any bodges. Op-amp choice. The NE5534 has low voltage noise and is great used with low impedances, but the TL074 has low current noise so is good used with high impedance like these filters. Transmission line vs port. I would say TLs are longer than 'ports' with a proportionally larger section area, are folded and use damping material inside to reduce harmonics of the main resonance. I'm already making improvements to the design for the final version in a number of areas.

No tweeter on the face of this planet is able to reproduce the frequencies of Dave's voice.

The venting on the back of the driver is for venting the voice coil. A difference between ported and transmission line is that transmission line adds bass over a wider frequency range then ported would.

Love the main Cap labelled as Flux Capacitor

Produced in DaveCAD - Unlicensed Version. :D

I am still using the speakers I built (and more or less designed) myself around 1981. I bought a book at Radio Shack that told you how to do it (there was even math involved) and I used my dad's tools to put them together. Around 2002 the old paper cones withered away so I replaced the drivers with nice modern ones and I replaced the crude crossovers I had built myself with modern boards. They've never sounded better.

10:26 Dave missed his own Easter egg.

"Produced in DaveCAD - Unlicensed Copy"

I'm not normally negative on other's designs, but those traces! I would have a fun time going through the board layout and putting a chamfer/45s on those right angles.

As an audio DIYer, my thoughts: Those midwoof drivers are A BEAR to work with. To get good low end you need a huge cabinet - at which point you can just use a larger driver with less nonlinear distortion. They also have nasty resonances in the upper midrange that you have to filter out with a more complex crossover to your tweeter. (Somewhat typical of aluminum cones, TBH, but it rains on the "small driver therefore high M/T xover point" parade.) IIRC, they also have a weird impedance curve that makes a passive XO difficult to design - not that it applies in this case. To top it off, the stamped frame is flimsy - I even had one arrive new, pre-bent. Once mounted, maybe that's not such a big deal, but I have a hard time believing it does not contribute to distortion when that cone gets moving - and its excursion (and small light neo magnet) is its point of existence. They can be fun to play with, but there are so many much better drivers out there if you're building a serious speaker. The tweeter, I've heard, is surprisingly good. I have a few to play with but haven't used them yet. They were used by a reputable name in the hobby speaker design circles in an omni-directional speaker design, and were found to be quite pleasant to listen to. In a nearfield or generic BT application, where the strengths of that driver don't apply, I would stick to a typical silk dome - it's better at being a normal tweeter. Dayton has some 1/2" to 1" domes that are a complete steal at their price. So overall, I feel like this design is a checklist of engineering experiments, not necessarily a great design in and of itself. Most DIY speaker guys go through something like this because it's unusual and therefore interesting. But it's unusual because many of the tried and true designs are just better suited for general use. There's always a fascination with making the smallest cabinet possible as well - but physics wants a Cerwin Vega floorstander, and clever engineering can only get you so far. Second best, for "good enough" cases, is a stout small driver with tons of DSP. Everything else is a compromise.

Although the full-range driver can be used without a tweeter, it will become more directional as the frequency increases making essential that you be directly in front of them to hear the full range. By crossing over to a tweeter, you can avoid that beaming effect.

Got to say the beech plywood does work well for diy speakers. I build them like this all the time!

I like the inverted dome tweeter. That way you don't have to reverse them after the kids push them in. :-)

Vishay caps are quite good actually. We use their tant's at my work for making all our RF boards and Vishay is prime spec with no allowable sub's b/c of the strict temp. profile the systems is designed and tuned to operate in.

As an audio pro I can tell you your comparison setup with the mic was better than most pro audio comparison videos. Good call

electrons flying off the corner, thats good stuff!!

They look like nice little speakers but the price is over the top. It would actually be cheaper to make your own.

Hi dave, the grill is to cool the voice coil down. When the subwoofer moves it blows air in and outside the little hole, cooling down the voice coil

Putting the price aside, I wouldn't use these for any critical listening, only for checking mixes. These drivers are too small to have a much wider frequency response without using tricks. Also, these would not work well for surround setups either, as you have to use them as a pair. No monitor in that price range has a slave passive speaker. They all have their own preamps and can be used by themselves, so you can buy the monitor as a single unit for surround setups. Also...if the monitor is that flat as claimed, why the plots are shown with averaging and with the large division of 20 dB per octave? Just give the full frequency response of the monitor.

So, some thoughts on the review. Quite right to be dismissive of the cabinet being a real transmission line. A few have already noted this. The original "transmission line" design went back to Bailey, and was a design with essentially no theoretical underpinning. The idea was that the stuffed tapered line would adsorb all the energy off the rear of the driver was a nice idea, but the reality was always going to be something else. There is now quite good understanding of what is really going on, and a few useful design tools available, Martin King's work probably being the definitive, although tools like Hornresp can also model the system and get much the same results. What the enclosure seen is is a tapped line. The port is coming off part way down the line, and you will get a reasonably complex system. There will be a resonant system in the box with the speaker, and other in the box with the electronics, they couple, and there is a lossy resonant port. Add to that a quarter wave resonant system end to end. However, what you can do is tune this mess to produce a range of responses, and with care eventually end up with a flat response. For a small enclosure you might be able to create a more satisfactory (for some definition of satisfactory) result than a simple sealed or ported alignment. On the subject of full range drivers, an eternal problem with any full range driver is the polar response at high frequencies. As the driver becomes large relative to the wavelength the speaker becomes quite directional. Whilst it is possible to make a flat response on axis, the frequency of the energy in the diffuse field is heavily skewed. Metal cone drivers invariably have a few quite nasty resonances at high frequencies, and part of the art of crossover design is to avoid energising them. All full range drivers, no matter what the technology, have significant resonance issues. One notes that the bass drivers are about 40 USD each, and the tweeters are probably in the vicinity of 10-20 USD. So the BOM for just the drivers is already 100 USD. Cutting out the enclosure on a home gamer CNC router is not going to be conducive to a cheap result, even if the kit probably goes together with the precision of a Swiss watch. The driver selected seems pretty nice. It has such nice design features as a shorting ring around the voice coil, and has clearly been carefully optimised. It is great for a small 2 way. One notes there is a subwoofer output. Does using it place a high pass before the bass drivers? Using it with a subwoofer would help greatly with reducing the excursion the drivers need, and would probably drop distortion quite a bit. With Dave's experience in building stuff for manufacture, some comments on the expenses, and the margins would have been illuminating. Despite the apparently high cost of these speakers, and the moaning, it is not clear how unreasonable the price is. Without serious economies of scale, getting prices down is hard, and in the end, it isn't the ingredients alone that matter. If the final result is good, that is what you pay for. The modern world doesn't seem to value the work in getting it to that point, and expects the IP for free.

That Dayton driver is a series piece. All you need to look at is the huge buna-n surround, huge magnet and then that deeply pleated nomex spider and a stiff cone. Seeing the nomex spider did it for me. If they are specing a nomex suspension, then they put the money in the right place.

That heat sink on the back should be mounted with the fins running top to bottom. Cooling will be compromised the way they’ve done it. At 15:20 it’s obvious the rear panel seal is only fitted down the sides, not the top and bottom. That could cause a few problems with the sound. They should be completely airtight except for the transmission line port.

I'm stunned at the amount negativity towards a product, which by comparison to far eastern standards is very high quality. The number of comments that say they could build them for $100 is shocking. This of course is a complete impossibility, especially if they are to sell them at a profit and stay in business. Ok the design of the PCB could be better, with more care taken with the layout. But in low frequency applications, it really makes little difference to the way the circuit functions. These are also pre-production samples, so there's going to be some elements of the design that won't get into the finished production models. So can we stop with this "I could build them for 100 bucks" bullshit, because you can't period. If you can, then do it and send them to Dave for evaluation.

This is definitely not a transmission line - the port is way to short. For a tuning frequency of 70Hz (like the frequency response suggests), the line would have to be about 120cm long. It´s a ported enclosure - which isn´t bad...just don´t call it a TL.

I've spent my life fixing Pro audio and lighting and for the most part they work. Right angle tracks aren't an issue at those frequencies. As for recording, Doug Ford will tell you the same thing. If a producer can mix a track and make it sound good on crappy speakers, it will sound great on real ones. This does not work the other way around!

I've heard these a few times and it's important to put them into context - for current use and the history behind the design. They are designed to be flat and accurate, a monitor speaker and therefore somewhat at odds with the norm for small multimedia speakers which are often hyped in the presence region to give added bite and excitement, and boosted in the upper bass for additional thump. Such anomalies sound impressive on first hearing but can become tiring after extended use, not to mention you are overlaying a set of defined tonal characteristics onto every performance. The LBM tries to avoid this by remaining clean and neutral. The ply cabinet is better damped than many other materials, lacking for example the high Q ringing often found in MDF and some plastics which colours mid range frequencies. I'm sure Simon could make these more cheaply with MDF, and even save some time on machining and finishing - but they'd sound worse.

Back in the 70's I read an interesting article about doppler distortion in wide-range speakers. In fact you will have a moving sound source when playing, for instance, a 5 kHz tone on a membrane that moves with a lower frequency like 50 Hz.

these are NOT MLTL speakers and the drivers do not appear to be high quality. Notice how none of the driver specs are given here or on the kickstarter. Go to partsexpress.com and you can build your own bookshelf monitors with an active crossover and add a blutooth module for a fraction of the cost. The $100 mark is not far off depending on how good of a crossover you want to build. Also, anyone that knows about resonance understands that for the density to mass ratio and quality control of the product, MDF is a better choice for cabs than plywood unless he is using the finest grade cabinet ply (9 layers or more) and checked for inclusions in the cab. This is a set designed for the recreational person who likes to think they know about something because they screwed nut A into hole B. Just an FYI, I built 3-way MLTLs as my main fronts and the crossovers in them were $300 so please do not mistake a product produced for noobs for quality just because the uninformed think it is.

The midwoofer is a reputable unit, but I don't know about the tweeter in the LBM's. They look like they are 1" Tymphany wide-range speakers, kind of like the Harman Odyssey single-suspension mid-tweeter speakers, so they probably aren't "junk" but I haven't heard them sound better than actual edge-driven dome tweeters in my experience. A "transmission line port" was originally done by Irving "Bud" Fried back in the 70's; my parents' old Fried Model Q monitor speakers had them, and they were called a "line tunnel" - effectively they are a lossy port, also called an "aperiodic" port. You actually lose a small amount of deep bass from this approach but you can flatten out the impedance peak of the woofer which makes them a better load for tube amplifiers with their higher output impedance so that the load the amp sees is less reactive. The Scan-Speak Scan-Vent and the Dynaudio Variovent are similar in practice. AudioSmile has been around this block before with some passive monitors using reputable drivers from SEAS in Norway, using passive crossovers.

Red painted screws, what kind of arbitrary expectation is that?

I still think these "chip amp" are all to often overlooked. I've run a DIY LM3886 amp for around 8 yrs on a set of floor standing TL speakers (DIY of course) they rock for the cost and are great little projects. Currently have version 2 in the pipeline.

Venting the magnet reduces first resonance frequency, not unexpected in a smallish wideband driver (headphone drivers often do the same). Good attention to detail in construction, parts appear to be nothing earth-shaking but of decent quality. (Yeah, the heatsink could be better, but eh... it'll do.) The speaker link jacks look like those used for radio mics to me... 4 contacts are just what you need for two drivers. Looks like single supply for the main power amp and split supply for the preamp stage, I wonder how this goes together... center-tapped AC input with 1x bridge rectifier + 2x half-wave? Pricing is not budget basement, but I mean, these are made in moderate numbers in the UK, not cranked out by the thousands in China, so both economy of scale and labour costs would be working against them.

IME, the tweeter is what usually fails before the main driver. If the tweeter is not replaceable without destruction of the cabinet, these will become throwaway.

The hole in the magnet (with the grill) is 1, to prevent pressure and vacuum building up in the dome of the woofer, and 2, for cooling the coil.

It's stupid of course, but after multiple recodings, improvised test set-up and my poor speakers and ears the Little British Monitors sounded more natural and with flatter response.

I really like BC caps(and Vishay branded plastic ones). Electrolytics are most of the time quite a lot cheaper here in EU than comparable series japanese ones. Nice to see them used here.

You are right Dave. They should put the PCB on the outside and put covers on both speakers to keep the symmetry, inside and out.

Transmission line converts the sound waves from the back of speaker and changes there Phase so instead of cancelling out they add to what is coming out the front of the speaker.

Like electrical transmission lines, an acoustic transmission line is supposed to present the driver with a constant, characteristic, impedance. I doubt that is what this one does, and even the best ones, on a proper scale, fail. They aren't really supposed to output anything at the end, and I have never fully understood quarter wave transmission lines because they never add up to Unity. In contrast, a ported cabinet presents anything but a flat impedance to the driver. It's essentially a second, lower, resonance below the driver's main resonance which serves to extend the bass response. (You don't get two peaks as one might imagine, but get a smooth shape if properly designed.) The price you pay for this is a sharper rolloff because you have introduced two new poles; in the mass of the air and the compliance of the air in the box. They are very different things indeed. I hope I have elucidated the difference.

Dave, I’m a little disappointed that you didn’t fix the symmetry of those tweeter decals while you had the thing taken apart.

As a line array of small drivers those woofers do work pretty well. You need 30 of them to get a decent bottom end and usually in an infinite baffle configuration. 30 x 1" ports equals a 30" port. Equally those 3½" drivers add up in surface area quickly too. For those drivers to be effective they have to be used in something like a Bose 509 configuration. As for the unpopulated area of the board, I have a hunch that it was for a USB DAC which ironically would have been better than the bluetooth save for the wireless part. You also may want to work the drivers in before you pass judgement. Often the compliance of the driver increases over time. It's like a leather wallet that needs to be worked in a bit before it feels right. I got a set of these and honestly they don't compete with my JBL 4312g but they are rather impressive for the size. Their heaps cheaper too for the level of audio quality possible with these.

I can confirm that those are not transmission line ported enclosures, in fact the angle is not smooth and will affect significantly the velocity.

Back in 1973 a coworker and I working at HP in Colorado Springs, CO started an audiophile speaker company, (Green Mountain Audio,) that is still in business 50 years later. So I know a bit about speakers, and can confidently say to your subscribers that so do you. Cheers.

A completely improperly designed audio cabinet, including electronics. Have you noticed the ceramic caps in the signal filtering? Jeeeez...

i use those switches(power) in my detectors, and there is a low profile version that if used in this would mean it didn't need those wire links on the power socket, the power board could be soldered flush.

Rear heatsink is the wrong orientation.... Noobie mistake right there.

FYI front porting doesn't mean you should stick speakers near walls or corners.

What really puzzles me is how it can be designed with different high frequency dispersion patterns between the left/right channels. The way the acoustic lens on the tweeter is implemented is really wierd.

My biggest issue with the speakers is that they do not have balanced inputs. Most professional studio monitors have balanced input through XLR connectors

I cant believe you really missed the soldermask saying "Flux Capacitor" next to the main Cap. What an epic fail for a "Back to the Future" Fanboy.

Dave its the reason only small monitors have all the power amps in one speaker. Most studios NEVER use anything smaller than a 5 " .MONITOR.

Besides calling it "rubbish" what is the problem with Blue Tooth? I like it.

The very best thing for speakers is MDF or HDF not plywood... it’s pretty simple, the heavier and more dense the material the better, the goal is energy absorption... and plate metal on the back is not great... flat amplitude response is great, how about the phase? You can EQ any system ‘flat’ and it will sound horrible... it’s much more about phase and the lobes in the off axis pattern...Their is no real difference in types of tuning, a port is a port, unless it’s horn loaded. Also the foam used is to increase the apparent enclosure volume by keeping the thermal load constant (isothermal), pretty sure that type of foam is not correct. Anyway it’s nice to see young folks experimenting with this stuff, unfortunately MP3 pretty much killed off HiFi simply because it’s an easy to use format, it’s incredibly difficult to find high fidelity signal sources these days.

Those four pin connectors aren't DIN. They are GX16 aviation connectors.

using an automotive TDA chip amp is actually smart ive never seen that before. ive only seen them use 2 seperate chips

Why the Bluetooth hatred? I'm gonna bust out the oscilloscope and test this! Disclaimer: I don't necessarily like Bluetooth. It just works faster than most Wi-Fi devices, so it wins by indirect default.

Being transmission line, you’ll have a bit lower bottom end, which is good, given their size. Also, your mid/low driver will have more freedom of motion, if he properly tuned the transmission line.

EEV - Time to whack out Doug's precision measurement microphones for frequency response.

I might be missing something here. On the website it states the power output is 4 x 50w, but the power supply is 6A@15v which equates to 90w. So how the hell can you get 200w power out from a 90w power supply ? - do those flux caps double up the power :) I'm also no expert, but for the money there are better finished speakers out there. He could have added a veneer to the front edge rather then leaving it exposed plywood.

Hmm, likely Baltic Birch (aka Russian Birch) so there are more lamination and less voids then normal 1/8" laminated plywood. Just me but IMHO it would have been better to edge trim the wood though... Cheers, - Eddy

The hole in the back is for cooling the voice coil, the grille of for keeping things out of the pole piece.

That's not a Transmission line, it's simply a flat reflexport. Still looking like a good pair of speakers though:)

Run lower frequency sweep with mic pointing at the woofers to find out if electronics make a difference acoustically between left and right

From the data sheet info that's a terrible (Muriel) choice of a chip. LM1875?

I owned some Ohm Walsh 2's with transmission line drivers and port. Very good sound reproduction and very pleasing to the eye. Don't thin I could fit them anywhere these days.

I feel like he is going for the hipster market. A true audiophile ( the usual market for a speaker this price)would probably laugh at these "monitors" . MC Frontalot FTW! I thought I was the only guy who listened to nerdcore

I don't like them... Someone made these and think they are nice and are proud of them - I respect that, but I don't like them at all myself. Cable between the speakers is not my thing either, but dude Dave - these speakers are so small - you will *never* be able to hear any difference between the active and passive box. No way. Unless there is something wrong with it. Potential loss? In this specific case, that's moving into the audiophoolery domain :P. These might be fine as speakers on your computer desk, or even as speakers for the TV, but would I put them in my audio studio? Nope. That's not what these are built for - but they certainly price them and name them to sound like they did. Nope!

Maybe "balance" the left-right volume by putting a Lithium battery in the second one to provide not just offline power but to reduce the size of the mains brick to deal with only the average power.

I swear this guy used to do the voice for Dickie Knee

This terminology gets me every time... I was ready for some nice video monitors when I saw the notification.

that response graph is pretty good, they actually do 60hz at 0db or 90 whatever way you look at it?

THREE HUNDRED POUNDS for tiny speaker KIT? Dafuq? You can buy really nice speakers for that. My Tannoy Revolutions were less!

Not a fan of controls on the back of the monitor. A small box for the amp and the controls would have been better. Would have also resolved the dissymmetry. But good on him anyway.

So one monitor, with an external speaker. I think I would prefer a small shielded box with front controls and rear I/O with two external speakers. You could also design a matching stand for the amp box. Who is it aimed at? I am supposing PC speakers for those with space issues?

They are on sale now btw, a few years after this video. Price: £529.00. I hope they have been improved a lot.

Naomi Wu's build is worth checking out...this is giving better technical info but Naomi's build is always worth your time....

You should give a try to the Neumann near field monitors.. amazing things.

Transmission line speakers should be totally non resonant.. Start out with the square footage of the "pipe" being a fair bit larger than the active area of the speaker.. (fair bit of geometry there..) a 10 inch woofer would start out at about 80-90 square inches..that will taper down to the active area of the woofer at the exit. Built a number of them over the years.. the drivers have to be selected for the job to get good low end response.. I measured my 4' tall designs with a 10 " woofer solidly flat down to below 50 Hz...Fed with a fairly decent little amplifier setup...The transmission line (the "tube" needs to be carefully filled and packed with long fiber wool... hung lin small baskets. You tune the speaker by changing the packing of the wool.. and they are all different.. (Lots of particle board for the walls to keep it non - resonant..)

Hi EEVBlog, Can you please let me know which is the best budget scope to buy in 2018(Is rigol 1054 still a contender), Thanks

Dave, I wonder why is most vintage stereo audio is better than newer stereo audio? At least, that is what everyone said it at online.

@17:40 "yes its upside down so all the electrons are gonna fall out" no, its right side up, you're down under so its compensated.

Transmission line ports aren't always better than typical ports, but in cases with small woofers they often times are. Ideally, the area of a T-line port should be the same as the moving cone area of the woofer, and the length of the port (in combination with the area) determines the lowest tuning of the enclosure. Similar to a clarinet, trombone, or really any other instrument, the length of the port in a T-line enclosure determines its lowest frequency, or in this case, it's cutoff frequency. At 3:40 you said that Simon mentioned that it's harder to make T-line enclosures for smaller speakers. I really don't understand where he's coming from with that. From my experience, it's much more difficult to do T-line enclosures with larger speakers since they require much more area for the port and end up taking a lot of space. Whether they're large or small the math is all the same, but maybe I'm missing something.

Been a while since I've seen anyone dabble in transmission line enclosures. I believe they were also called an acoustic labyrinth, requiring multiple baffles combined with a specific weight and volume of damping to slow the rear pressure a full wavelength instead of the half-wave of a tuned port, resulting in a flatter response and without the common 'muddy' sound of the latter, the reason acoustic suspension has superior phase harmonics. Bose has produced a few models featuring these types of enclosures, and I remember someone years ago using plastic conduit to create some Dr. Seuss arrangements for the same effect. Good stuff as usual mate! ~A. Lurker

The grill is to allow airflow around the coil, it's for cooling.

Just get a junk circuit board, hack it to size and install it in the passive speaker to approximate the presence of the active board in the other speaker. :)

"Produced in DaveCAD -Unlicensed Copy" Hahahaha

Swan makes a 3-way speaker kit for $290 on Amazon that you assemble the enclosure and the passive crossover. They are passive so you will need an amp, but reviews say they sound great.

Cambridge S30's are a bit better small speaker option but they are passive.

Those goddam 741s ... You can't get away from them if you tried. A studio esp in the 70s and 80s had mixers with hundreds of the buggers in em. Your favourite tunes probably been through 1000,s before you put them through your single ended triode...

I think the holes in the back of the woofer are a cooling port, I think you were mistaken about the sound going through the foam, the sounds goes past the tweeter to the top of the speaker then into the wave guide thing

Damnit. I built almost this exact thing but with a DSP and class-D amps over 6 years ago. Never put them on the market

The reason why people don't do these kits anymore? Because there is no profit on it unless you ask a ridiculous price like these. I know pretty much which drivers are being used. At my company we sell something similar monitors for just around 80 bucks. And those are sold per around 500 per year. I am far from impressed for the amount of money

Marco Reps made some a few weeks ago but nice to see the coverage.

I can't believe the amount of suckers that paid that much for a set of speakers built around measly $30 drivers. Yikes!

interesting speaker set up. soldering inside is hilarious. what you call a monitor i call a speaker.

Hi Dave, here in Britain, our houses are 35% the size of the rest of the world. Thus we are also 35% shorter, and out speakers come in smaller sizes... /s

The LBM and Focal speakers sounded the same to me, but then anything would coming out of my old $100 Altec Lansing monitor (as in PC monitor) speakers with separate subwoofer. Also, while I agree that the acoustics will be slightly different between the one with the PCBs inside and the one without, I seriously doubt anyone could hear that difference. Needs a blind test to be sure.

I think they sound a lot alike, but the Focal ones are a bit crisper on the treble... Depends on which you consider more accurate. I assume neither has base.

I still use a pair of 1960 15" 15 Ohm Tannoy Monitor Reds in transmission line 12 cubic feet cabinets (around 180lbs each) . I paid £5 for both chassis (they were going to be dumped) and needed a bank loan for the cabnet materials. The BBC used these quite a lot. I have listened to others in my home but like most things one mans meat is another mans poison. You can read all the write ups you like, look at all the data sheets there are but reverberation times, room acoustics, and our ears can make or break any setup. I lost interest when the lack of coloured screws came up.

Seven hundred u.s. dollars for an amplifier with 10% distortion? Aptx and, aptx hd especially, make a difference in sound quality but any efforts at sound quality are negated by that horrible amp chip. The whole thing seems to be put together from internet research by someone who doesn’t really have an interest in audio quality. In sourcing parts for my own build of a bluetooth speaker into a vintage boombox I’m acquainted with all the components used here and there is a definite mix of good and cheap components. The “tweeter” is most likely another full range speaker. True tweeters are built with sealed backs and wouldn’t need their own enclosure as was done here. The build is incredibly amateur or intentionally cheapened to make the most money. Dave went easy on the guy.