Scan Speak 10F/4424G00 Discovery 4″ Midrange (4 ohm version)

Up for test is the Scan Speak Discover 10F midrange.  This driver features a neo magnet to keep its weight down.  Accompanied with the extremely small form factor, this is a top choice for many in car audio and home audio alike.  While this is noted as a 4″ midrange, seeing it in person makes it appear to be closer to the 3.5″ driver family relative to other 4 inch drivers.  This is a driver I often recommend for its price vs performance, though I’ve never gotten the chance to test one until now…

IMG_5348 IMG_5350 IMG_5349

Small Signal Analysis

Electrical Parameters
Re 3.18 Ohm electrical voice coil resistance at DC
K 0.0098 LEACH inductance model
n 0.52 LEACH inductance model
Cmes 208 µF electrical capacitance representing moving mass
Lces 6.58 mH electrical inductance representing driver compliance
Res 9.58 Ohm resistance due to mechanical losses
fs 136.1 Hz driver resonance frequency
Mechanical Parameters
(using add. mass)
Mms 3.524 g mechanical mass of driver diaphragm assembly including air load and voice coil
Mmd (Sd) 3.266 g mechanical mass of voice coil and diaphragm without air load
Rms 1.768 kg/s mechanical resistance of  total-driver losses
Cms 0.388 mm/N mechanical compliance of driver suspension
Kms 2.57 N/mm mechanical stiffness of driver suspension
Bl 4.116 N/A force factor (Bl product)
Loss factors
Qtp 0.447 total Q-factor considering all losses
Qms 1.704 mechanical Q-factor of driver in free air considering Rms only
Qes 0.566 electrical Q-factor of driver in free air considering Re only
Qts 0.425 total Q-factor considering Re and Rms only
Other Parameters
Vas 0.764 l equivalent air volume of suspension
n0 0.327 % reference efficiency (2 pi-radiation using Re)
Lm 87.34 dB characteristic sound pressure level (SPL at 1m for 1W @ Re)
Lnom 88.34 dB nominal sensitivity (SPL at 1m for 1W @ Zn)
Sd 37.28 cm² diaphragm area

10f impedance

Large Signal Analysis with Klippel’s LSI Module

Displacement Limits thresholds can be changed in Processing property page
X Bl @ Bl min=82% 1.4 mm Displacement limit due to force factor variation
X C @ C min=75% 1.7 mm Displacement limit due to compliance variation
X L @ Z max=10 % >2.2 mm Displacement limit due to inductance variation
X d @ d2=10% 8.8 mm Displacement limit due to IM distortion (Doppler)
Asymmetry (IEC 62458)
Ak 8.89 % Stiffness asymmetry Ak(Xpeak)
Xsym 0.95 mm Symmetry point of Bl(x) at maximal excursion
Xpse 2.7 mm

Scan Speak 10F Force factor Bl (X) Scan Speak 10F Bl Symmetry Range Scan Speak 10F Kms Symmetry Range Scan Speak 10F Stiffness of suspension Kms (X) Scan Speak 10F Mechanical compliance Cms (X) Scan Speak 10F Electrical inductance L(X, I=0) Scan Speak 10F Inductance over current L(X=0, I)

Frequency Response with Klippel’s TRF Module

Scan Speak 10F4424G00 0 30 60

Harmonic Distortion with Klippel’s TRF Module

The following is HD results at both 90dB/1m and 96dB/1m equivalent.

10f hd 90 10f hd 96

Cumulative Spectral Decay

10f Cumulative spectral decay

Thoughts

As this is a pure midrange, the xmax values provided by LSI aren’t frightening.  If you want to cross low, there’s not a lot of displacement so it’s best to use this with a woofer and cross above 300hz.  Judging by the rolloff, toward an Fs of 136hz, you’ll likely need to EQ assist the response below 400hz. Another benefit of this driver is it doesn’t require a large enclosure.  My measured Vas is approximately 0.7L, and the lower Qts of 0.45 allows you to go a tad below the Vas value to reach a Qtc of 0.707.

The overall frequency response of this driver is pretty nice, maintaining a fairly flat response in what I would call two ‘sectors’ of response; divided by 1.5khz.  At this point, the response dips a bit and increases by about 3dB to 2khz where it is fairly flat.  I’ve never been one to propose using wideband or fullrange drivers due to the lack of top end response and typical varying response above the pistonic range (aka: tweeterless) but in this case, I think one would be OK to do so given the extension through 20khz and smooth, controlled off-axis response.  There are no major nodal issues to speak of here; it seems the nomex cone is doing a good job of keeping break up to a minimum.

In line with that, THD results suggest a crossover above 300hz.  The bump in HD around 400hz is a driver-borne result.  I tested it a couple times in a couple different manners to see if it showed up consistently and there is nothing in the setup that would be the cause.  3rd order HD is quite nice, staying well below the 1% threshold above 200hz.  Subsequent even and odd-order distortion is very low.

All in all, not the world’s best results but as a midrange in a 3-way system crossed above 300hz or (as high as 500hz) this makes a very fine driver.  If one wanted, they could build a very nice 2-way speaker with this as well and let this driver handle everything above 300-500hz.

3 thoughts on “Scan Speak 10F/4424G00 Discovery 4″ Midrange (4 ohm version)

  1. Nice review, very inspiring.

    I’ve been considering this to be used in my Mazda CX5. I am planning to use 3 stock locations (at front dash) to install this thing, and for frequency below 500Hz, I will have SS woofer and Focal Coaxial to help. It seems your graphs justify my plan

  2. Excellent performance. These 10f’s (both the “midrange” 4424 and “fullrange” 8414 models) are an excellent value, especially when considering they used neo in the motors as well.

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