North Creek Music Systems
Micro-Monitor and Surround Loudspeakers
At right is the North Creek "Echo" loudspeaker, in a ribbon mohogany cabinet made by Lee Taylor.
This is a great little loudspeaker, built with quality drivers and crossover parts, and is easy to assemble in a single evening. Placed within one foot of a wall, the Echo has a punchy midbass, is smooth and articulate through the midrange, a seamless transition to the top end which is sweet and beautifully detailed as only one of the best silk domes can be.
This is a true "Bookshelf" monitor. Its profile is about that of an 8 1/2 x 11 sheet of paper (or a typical book), while its narrow width means it takes up a minimum of shelf space. Likewise, its considerably weight makes it well suited for book ends. Fully shielded and with a footprint smaller than most stationary, this loudspeaker was designed for stereo, computer monitor and 5.1 channel audio-video applications in small and mid-sized listening rooms and with a good subwoofer easily outperform most loudspeaker systems costing many times the price.
The Echo comes in component form, crossover unassembled but with detailed cabinet drawings and crossover assembly plans that can also be directly downloaded from this site. Drivers are top notch - the North 13W-06S 5" woofer and shielded version of the North D25-06S silk dome tweeter. Assembly encompasses all aspects of speaker building and is an excellent project for the beginning speaker builder and/or audiophile looking for more insight into the loudspeaker manufacturing process.
Echo Bookshelf Monitor Kit …$sold out
Echo MTM Center Channel Kit ...$sold out
Echo MTM Mini-Tower Kit ...$sold out
Echo SYSTEM (One pair of monitors, one center, and one pair of Towers) ...$sold out
Echo Cabinet Plans
Echo Crossover Assembly Instructions
Echo-C MTM Cabinet Plans
Echo-C MTM Crossover Assembly Instructions
Echo-T MTM Mini-Tower Cabinet Plans
Echo-T MTM Mini-Tower Crossover Assembly Instructions
Below is the Echo frequency response family.
Frequency response is 85Hz - 20kHz +-2dB, rather remarkable for a loudspeaker priced well below $1k (or in this case, below $150). Yet this performance was accomplished with a very simple crossover network, so the crossover components employed can be of higher quality while still making the price point. System sensitivity is 85dB.
The only significant dip in the frequency response is the dip from 2 to 5kHz. Fans of the Rogers LS3/5A will immediately recognize this as the classic "BBC" dip.
The antiphase null is over 20dB, indicating perfect phase addition between the drivers and an absence of off-axis frequency response peaks.
The crossover topology is shown at right. This is a simple impedance compensated first order low pass for the woofer, and a standard second order with resistive attenuation for the tweeter. Component values are:
L1 = 2.20mH
C2 = 8uF
L2 = 0.56mH
R2 = 3.32Ω
R3 = 6.00Ω
As this loudspeaker is destined to be used with a subwoofer and to be compatible with audio-video receivers, drive-ability is a key issue. We therefore set the minimum impedance to be 6.0 Ohms (a little higher than most nominal "8-Ohm" systems).
The Echo's fundamental resonance is 98 Hz, perfect for a loudspeaker intended to be used with a subwoofer, and mating it to a sub is straightforward. Its natural roll-off below 100 Hz is exactly what is called for by all of the major surround formats, with the main and surround speakers set to "small". However, as most receivers with built in processors do not have a steep enough low pass subwoofer cut-off, it is strongly suggested that one employ the subwoofer amplifier's additional second or third order low-pass slope. This can be set as high as 200 Hz and will still benefit the system's overall performance. A single Poseidon sub is the recommended match.
Designing a loudspeaker for near-wall placement is much more difficult than for free-field, as there are two sets of boundary conditions with which to contend (the corners of the fascia and the wall behind the loudspeaker).
Here by incorporating the woofers natural rising frequency response and roll off with the first boundary condition, a simple first order low pass network (with impedance compensation deliberately tuned about an octave above the crossover frequency) produces the desired third order acoustic roll off. The series inductor is much smaller than would normally be called for because the second boundary condition partially eliminates the 6dB baffle diffraction step. The overall woofer performance of the North 13W-06S measures +-0.5dB from about 100Hz to its transition point around 1kHz (well over three octaves). Below is the assembled network, built by North Creek's Inside Sales Manager Windy Kelley. This is a 16 gauge Music Coil air core inductor, film capacitor and North power resistor. Wiring is OFHC copper, gold-plated connectors. All wiring is point-to-point, crimped-then-soldered.
The high pass is also simple because the North D25-06S tweeter was designed specifically for this cabinet width, the slight anti-plateau around 2kHz interacting with the cabinet's acoustic field to create a net frequency response that is very easy to work with. The tweeter network is a simple second order high pass with resistive attenuation. Below right is a close up of the assembled tweeter network, also by Windy, whom apparently has stock in 3M's silicone division. Again, a film capacitor, Music Coil inductor and North power resistors. Wiring is Tef-Flex silver-clad copper, Teflon jacket, gold connectors. Simply exceptional component quality for a loudspeaker at this price point.
I must emphasize that the Echo - like all North Creek loudspeakers - was designed almost exclusively by ear. It is very tricky to voice a loudspeaker properly when it has limited bass response. The natural tendency is to keep reducing the midrange and top end to create the illusion of bass by emphasizing everything around 100 Hz. The Echo has succumbed to this to a very tiny degree, as evidenced by the very slight hump around 125 Hz, and it actually sounds much better this way than "flat". When used without a subwoofer - in a dorm room or bedroom, for example - the hump rounds out the bottom end nicely and without disturbing the neighbors.
Adding a Poseidon subwoofer brings out an entire new dimension. The Echo's seem to vanish and the sound field is enormous. The key to doing this properly is to block everything from below about 150 Hz from getting to the Echo's. Most surround sound processors have this capability built in, but for those that do not, one can use a simple splitter between the pre-out and amp in, driving the subwoofer full range and the main amp though a passive first order network (a 0.1uF Crescendo capacitor tied the RCA plug center pins works nicely). As odd as it seems to mate $150 a pair speakers with a $400 subwoofer, the fact is that the key to building a good sub is to start with a good amp, and good amps are expensive.
Because the crossover network uses so few components, we are able to offer this loudspeaker with much better sounding crossover components that would normally be possible in a loudspeaker anywhere near this price. Crossover components include 16 AWG inductors, film capacitors, and North power resistors. All components are hand matched to +-1%.
This loudspeaker does have its limitations. At $14 each it is impossible to have Faraday Rings or sleeves, so the North 13W-06S does not have the excursion or resolution of a Scan-Speak woofer. But here with a very good sounding paper cone, nylon dust cap and acoustic suspension cabinet, we have gone for sins of omission to get the most out of it. The North D25-06S tweeter will take on the character of the crossover parts through which it is driven, and here even though we are using a $1 film capacitor, we still used $4 North power resistors. All the hype and banter aside, good sounding resistors are the most important part in any crossover network and the North power resistors are the best.
My guess it that in a retail store one would have to spend between $600 and $800 to get a speaker as good as the Echo, and in fact there are a lot of speakers out there that are much more costly and nowhere near as good.
The next to additions to the family - the Echo_C MTM Center Channel and the Echo-T MTM Mini-Towers - evolved naturally both from the original Echo design goals and its near-wall placement requirements. The 5-to-7 channel system, with identical voicing for every channel, is a natural fit.
Comments on the Parts Express cabinet
At right is a photo of the Echo in a Parts Express #302-702 cabinet.
First and foremost, I would much prefer that those building North Creek loudspeakers considered purchasing their cabinets from our authorized vendor www.TaylorSpeakers.com.
I generally don't complain about getting ripped off (one kind of gets used to it after a while), so I won't bitch too much here. But the fact is that the Parts Express cabinets do show a striking resemblance to the North Creek look I created and have maintained since 1992. The cabinet deeper than it is wide, rounded over double-thick fascia, finished separately, then attached to the cabinet body via screws that are later hidden behind the grill plugs - this is all pure North Creek, straight out of the Cabinet Handbook and our drawings on the web. So I guess I should be flattered.
That said, we deliberately built this loudspeaker in a Parts Express cabinet because $100 for a fully veneered shell with grilles is very reasonable indeed. Other than above, my only major complaints are (1) they should have used plywood instead of MDF for the brace and (2) the fascia should be much thicker and primed but not painted.
The Cherry shown at right looks nothing like American cherry, but it is not unattractive. The Beech finish is excellent.
A Jasper Circle Jig equipped router with a variable speed control, the speed set extremely low so the bit goes "zzooop zzooop zzooop", made short work of machining the driver countersinks and though holes in the fascia. Then it was flipped and the flare machined into the woofer through hole. Naturally this scratched up the factory enamel pretty good, but as it has to be repainted anyway or the driver countersinks will stand out bright white. Sanding with 220 followed by a few coats of black enamel applied first with a foam brush in the countersinks, then a foam roller along the edges and the faces gave an excellent glossy finish with enough bumpiness to hide any imperfections. The best paint for this is Red Devil Acrylic Latex Gloss Enamel Satin Black.
The binding post holes need to be enlarged to 1/4" for the North Creek Big as Texas binding posts. These posts add $24 to the cost of the kit, so those on a tight budget should use a hole saw to cut a round hole for the standard single-wired back cup.
The crossovers were glued in place with Liquid Nails and everything left everything to dry overnight.
The following morning the fascia was glued to the main cabinet and that afternoon the binding posts, stuffing and drivers were installed.
All told, the cabinet work took about three hours total, building the networks about an hour and final assembly about half an hour. The Parts Express cabinet almost as good as the standard cabinet, not quite as "dead" but otherwise comparable. Those who do not have a table saw or the patience to veneer, like the idea of changing faceplates, or are on a very restricted budge - may wish to consider this route.
North Creek makes unfinished, 2-part fascias for the PE cabinets for $65/pair.
-George E. Short III, © June 2004, February 2006.
First, I have to say that my first foray into DIY and your Echo speakers blew away my expectations for a $200 speaker. Both myself, my brother and the people who came by to listen can't believe the sound and the workmanship of the cabinets (a little plug to myself).
We are now looking at a sub and particularly the Poseidon sub...
Just wanted to let you know that the new dome has arrived safely and that I managed to get the first pair of Echoes up and running. I must say these little speakers are truly amazing. The quality of the sound blow me away and at $149 I think the are a true bargain. Now I'm looking forward to comparing them to my upgraded Okara II.
I ordered an echo kit from you about a year ago for my father-in-law
who had been on the verge of buying some $900 overpriced B*** setup.
Obviously the Echo's paired with a PE 10" sub and a small receiver are
orders of magnitude better in so many ways. I just wanted to write to
send complements on a speaker that really fits the needs of a lot of
non-audiophiles. That is true for both the price and that it is
designed as a true bookshelf speaker with regards to baffle step
compensation. Telling my mother in law that stands 24" out into the
room were required would have been a deal breaker. Oh, and they sound
very nice too. They are nice and relaxed as they need to be for
sometimes dubious sources and upstream electronics. Thanks again.
I have been enjoying my Echo's for a couple of weeks, and just had to say.... Wow! I but placed them where I had a set of ~$700 name-brand floor standers which I purchased from a major store. While the little Echo's don't have the same range, they are much more musical and have all the detail without the forwardness. Simply put, they are more enjoyable to listen to! These guys are little overachievers!
Its clear these will be wonderful with a sub. I think a Poseidon will be my next project ;-)
(I am also looking forward to hearing my Casita's)
P.S. Hope your able to ride to/from work now....
> More than on year has passed.
> And, what can I say... The're great!
> Hope everything is going well.
> Here are a couple of pictures of the set. The sub is from Solen's... They
> are 30 minutes away from my place...
> I decided to change the shape of the speaker's in homage of Vincent
> of Totem Acoustic. He was my Math teacher :)
> Hope you like the pictures. Use them as you wish.