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Audio Nirvana Classic 4+ Fullrange Speaker Driver


Audio Nirvana Classic 4+ Ferrite Fullrange Speaker Drivers

The Audio Nirvana Classic 4+ Ferrite speaker drivers are among the latest addition to the growing product line of Audio Nirvana fullrange speakers. As the name implies, the Audio Nirvana Classic 4+ Ferrite is a 4" (100 mm) diameter fullrange speaker driver with a ferrite magnet. The Classic 4+ fullrange speaker uses a paper cone and what makes this model unique are "camel bumps" which shape the paper cones. The purpose of the camel bumps is to refocus sound that would normally be directed at the floor and ceiling towards the listener. The unique cone shape should make for a more detailed driver with more 'focus'. The speaker surround is an accordion style and made of treated cloth with a tacky coating. This style of driver construction should have a lifespan approaching 50 years. The speaker voice coil is 1" (25.4 mm). The ferrite magnet weight is 13 oz. (369 g) and the total weight of the smallish driver is a hefty 2.1 lbs. (950 g). From the datasheet the Audio Nirvana Classic 4+ Ferrite speaker drivers are capable of an extended frequency response that can cover from about 120 Hz to 20 kHz. The driver excursion is noted as Xmax = 2.15 mm. The build quality of the Classic 4+ drivers is excellent. The hefty little Classic 4+ speaker drivers are constructed on a solid black cast aluminum frame. Audio Nirvana stickers proudly adorn the magnet and back of the speaker.

Audio Nirvana Classic 4+ Ferrite Fullrange Speaker Drivers

Photograph 1: Audio Nirvana Classic 4+ Ferrite Fullrange Speaker Drivers

The Audio Nirvana Classic 4+ speaker drivers came neatly packaged in a cardboard box which indicated that the speakers were manufactured in China. The packaging included a tight fitting right plastic cover that slides over the cast speaker frame to protect the driver cone from fingers and the like during transport. A driver datasheet is included, however, a gasket and mounting screws are not supplied with the speaker drivers. The speakers shipped to Canada from Missouri, USA and the parcel was double boxed and very well packaged.

Audio Nirvana Classic 4+ Fullrange Speaker Driver Packaging

Photograph 2: Audio Nirvana Classic 4+ Fullrange Speaker Driver Packaging

Note - The 4" speaker drivers initially launched with the name Classic 4 Horn (Aug. 2016), however, the name was subsequently changed to Classic 4+ (Dec. 2016).


Thiele/Small (T/S) Parameters - Audio Nirvana Classic 4+ Speaker Drivers

The Thiele/Small Parameters of the Classic 4+ speaker drivers have been measured using the Dayton Audio Test Systems (DATS). The T/S parameters from the small signal speaker testing as well as the parameters noted on the Audio Nirvana Classic 4+ Ferrite datasheet are summarized in Table 1. The measured Thiele/Small parameters of the tested drivers were relatively close to the specifications noted in the driver datasheet and more importantly, the two tested drivers measured very closely to each other.

Table 1: Thiele/Small (T/S) Parameters - Audio Nirvana Classic 4+ Fullrange Drivers

 Parameter  Audio Nirvana Driver 1 Driver 2
Fs 122 Hz 136.6 Hz 134.6 Hz
Vas 1.9 L 1.6 L 1.6 L
Qts 0.63 0.69 0.68
Qes 0.78 0.86 0.85
Qms 3.3 3.5 3.5
Re  6.8 Ohms   6.6 Ohms   6.6 Ohms 
SPL 88.5 dB 88.8 dB 88.7 dB

Notes:
  - T/S parameter measurements made with Dayton Audio Test Systems (DATS).
  - Temperature = 22 C, Relative Humidity = 60%.

Figure 1 shows the superimposed impedance sweeps of the two Audio Nirvana Classic 4+ Ferrite speaker drivers. The measurements were made using the Dayton Audio Test System (DATS) and the two drivers are well matched to each other.

Impedance Sweep - Audio Nirvana Classic 4+ Speaker

Figure 1: Impedance Sweep - Audio Nirvana Classic 4+ Speaker


In-Room Frequency Response - Audio Nirvana Classic 4+ Speaker Drivers

The frequency response of the Classic 4+ is shown below in Figure 2. The measurements were made using a Dayton Audio OmniMic V2 measurement system. For the in-room measurements, the driver was mounted on a round open baffle with the microphone at the listening position located about 11 feet (3.35 m) away. The rise you see in frequency response between about 300 and 600 Hz is due the baffle diffraction loss (baffle step).

In-Room Frequency Response Audio Nirvana Classic 4+ Speaker

Figure 2: In-Room Frequency Response Audio Nirvana Classic 4+ Speaker


Datasheet - Audio Nirvana Classic 4+ Ferrite Fullrange Speaker Driver


Sound - Audio Nirvana Classic 4+ Fullrange Speaker Driver

Over the past several years I've been able to experience a number of 3.5 to 5" fullrange drivers made by Fostex and TangBand. I've used these small fullrange drivers for covering from about 100-400 Hz and up on an open baffle 2-way speaker system which uses an active crossover system. The Audio Nirvana Classic 4+ speakers share a number of similar characteristics with the sized Fostex drivers, such as the paper cones, large magnets and smooth warm sound particularly with vocals and acoustic instruments. However, the Classic 4+ drivers are also definitely quite different than the Fostex types, both physically and sonically. The unique "camel hump" cones of the Audio Nirvana Classic 4+ drivers are a rather interesting design. Relative to the similar sized Fostex drivers which can often sound somewhat forward and a touch bright, I would characterize Classic 4+ response as as more balanced and with better focus. This may be due to the camel hump cone design which is intended to redirect sound that would normally be directed at the floor and ceiling, towards the listening position. The more balanced response is conducive to long and even loud listening sessions without the onset of listener fatigue. For my Hi-Fi setup these sonic traits allowed for many improvements. The focused high end response of the Classic 4+ drivers blended in very well with my listening room, which while carpeted has a reflective ceiling and walls, and I would generally characterize the room as bright. Normally I toe in the open baffle speaker position with bright drivers so that they cross before the listening position, between about 20 to 30 degrees off-axis. With the Classic 4+ drivers I find that no speaker toe in is required and the benefit for listening to the drivers on-axis is a well focused and wider sound stage. The Classic 4+ drivers are well suited for use as part of a multi-way speaker system and could also work well as satellite/rear speakers as part of a home theatre system. Overall this is a very well built speaker that delivers good sound quality with great focus through the camel hump shaped cone.

The Audio Nirvana Classic 4+ Ferrite fullrange speaker drivers are available for purchase from CommonSense Audio. The drivers are priced at $138US/pair (Dec 2016) and that price includes shipping within the USA and discounted shipping elsewhere.