The Goal

MISCO’s goal was not to improve upon the NS-10’s mid-woofer performance but to exactly match its sound better than any manufacturer has done. The target was the driver used in the NS-10M Studio™, the product iteration most often found in recording studios.

Making a drop-in driver with a white cone is easy; getting a perfect sonic signature match is very difficult.

There have been several attempts over recent years to replicate the sound of the NS10 driver; MISCO’s engineers believe that none have been successful, including MISCO’s own attempt several years ago. At the time of their previous effort to make a matching NS-10 driver, MISCO did not have the advantage of having a full set of Klippel vibrational analysis tools in-house as they are now. As is shown by the graphs below, a recently introduced "drop-in replacement" by a well-respected competitor has fallen short of the goal as well.

Early on the MISCO team realized that frequency response alone is not a perfect predictor of matching the Yamaha’s sonic signature—but it is a vital first step. Other factors such as distortion, dispersion, and sensitivity play a significant role as well.

Fortunately, MISCO owns one of the most completely equipped loudspeaker measurement labs in North America – Warkwyn. Using Warkwyn’s state of the art Klippel laser-based Scanning Vibrometer, and Near Field Scanner MISCO engineers were able to pinpoint those factors that make an NS-10 driver sound like it does, and choose the materials and tuning needed to match the iconic NS10 sound.

The project started with a laser scan of the cone geometry to aid in perfectly matching the original. While some manufacturers have attempted to copy the NS-10 woofer using a seamless molded cone, MISCO found it necessary to use the same seamed paper cone design as the NS-10 to capture the very essence of its signature sound. As seamed cones with the right material properties were not readily available, MISCO opted to manufacture a paper pulp seamed cone in their St. Paul, MN factory.

This isn’t just a white speaker, resembling the NS-10 woofer, it is exactly like a NS-10 woofer. I couldn’t be more pleased with the result!” Kevin Szymanski, Producer, Mix Engineer - Nashville, TN

Based on their measurements the team built dozens of prototypes and measured them using the same advanced equipment used to measure the Yamaha. Ultimately, they came upon the combination of materials, alignment and manufacturing techniques that matched the NS-10 driver.

A MISCO MS10-W project engineer hand-delivered a set of the prototype woofers to Nashville recording engineer Kevin Szymanksi. Another pair of woofers was sent to Los Angeles-based recording engineer Joe Zook (U2, Katy Perry, Weezer, Brett Dennen).

With valuable feedback from these and other recording professionals, the team continued to tweak the design until they had zeroed-in on a woofer that would indeed be an ideal drop-in replacement driver for the thousands of NS-10 systems out there in need, or soon to be in need, of new drivers.

MS10-W prototype mounted in NS10M enclosure. Note the cone seam.

 

 

The Proven Result

Is the Bold North Audio MS10-W an exact replacement driver for the NS-10? The proof is in the measurements and the listening. The frequency response graphs below (Figs. 1, 2, 3 & 4) were derived by measuring an NS-10M Studio system, first with its original woofer, then with the MS10-W, and finally with a competitor’s replacement driver. The Bold North Audio replacement driver is identical to the Yamaha original. However, the recently released competitive replacement driver misses the mark in the critical midrange—the area that is most prized by engineers for its ability to reveal recording flaws!

Klippel vibrational scan of Yamaha woofer at 2kHz showing cone and surround breakup modes.

The scans below illustrate the phase nodes of the three cones at 3kHz. They perfectly demonstrate the vibrational effects of the seamed cone of the Yamaha™ and Bold North Audio drivers pictured with cone seams at “12:00” on the scan. The competitor’s model, without a seamed cone, has significantly different modal behavior when compared to the original Yamaha™ at this frequency. A critical listen to the three drivers confirms that the measurements are accurate predictors of audible performance.

Home Grown Quality

The Bold North Audio MS10-W is assembled in MISCO’s St. Paul, MN factory under the supervision of the engineers who designed it. Every single production unit is tested using Klippel quality control apparatus to ensure exceptional unit-to-unit consistency. The MS10-W earned “Klippel Verified” status, that indicates the state of the art Klippel equipment has been used from design all the way through to end-of-line QC. The MS10-W is packaged and sold individually, but MISCO highly recommends that NS-10™ owners replace both mid-woofers at the same time. Driver suspensions and other parameters change over time such that a new production driver cannot match the sound of an older driver. For the best imaging and sound staging it is essential that left and right speakers be as closely matched as possible. Replacing both mid-woofers with MS10-W units, in essence, brings the speaker system back to the sound of a new pair of NS-10s (assuming the tweeters and crossovers are working correctly).