Grundig EE1178

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NO SMOOTHING is applied to the shown plots. Most measurement sites have some smoothing applied which ‘irons flat’ sharp peaks and ‘wiggles’. I do not use smoothing because some info about sound quality is lost when plots are smoothed.

Aside from a small correction of the microphone itself also some correction in the lowest frequencies is applied to the plots to compensate for the perceived loss of bass when using headphones. This is described HERE in more detail.
A ‘horizontal‘ frequency response curve on the shown frequency response plots on this website thus indicates a perceived ‘flat’ tonal signature.

ALL measurements are made with a good SEAL on a flatbed measurement rig.
The shape of your head, bone structure, pad size, pad ‘softness,  (compliance), hair or no hair and or wearing glasses may (drastically) change the frequency response of some headphones, so… your personal experience may differ substantially from these plots.

Frequency response (tonal balance) is the most sound-determining aspect of headphones. A horizontal line shows audible neutral response in the plots on this website. Deviations in different severities at different frequency bands have an effect on the sound character.
The bigger the deviation the stronger the effect.

Below an aid to help determining the sound character of headphones with relation to the frequency response.

descriptors2

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Grungig EE1178 (wireless B.T.)

Grundig EE1178The Grundig EE1178 is one of the cheapest BlueTooth headphones around. It sells for anything between €12.-  and €25.-. For this you do get an all plastic wireless headphone with rechargeable battery and Bluetooth functionality and it is available in a few color schemes as well.
It takes about 5-8 hours to charge the batteries. Once charged they will last 3 to 4 hours.
It thus is connected longer to a charger than it can play music.
The comfort is very low. This is not caused by the weight which is pleasantly low.
This headphone looks like an over-ear but secretly is an on-ear. No ears will fit inside the pads. After an hour or so the top of my ears started to hurt.
The pads are made of  thick pleather (vinyl covered cloth).
The cups do not swivel and are fixed to the headband. This makes it difficult to get a good seal.
The sound quality is on par with its lowest price point.

specifications:

Type: On ear, closed, Bluetooth
Usage: Home, portable
Driver type: dynamic
Pads: replaceable, pleather
Internal pad dimensions: height: 45mm, width: 30mm, depth: 12mm.
Collapsible: yes.
Headphone connector: 3.5mm TRS
Cable entry: single sided (left side)
Cable: replaceable, nickel plated 3.5mm TRS jack 1.2m
Driver size: 38mm Ø
Nom. power rating: 50mW (estimated)
Max. voltage: 1.4V
Max. current: 40mA
Max. S.P.L.:  108dB
Impedance: 36Ω
Efficiency: (wired) 91dB/1mW (105dB/1V)
BT version: 4.2
Weight: 188 gram
Colour: black/grey, black/pink, grey, gold
Clamping force: medium
Accesories: 3.5mm cable, micro USB cable.

Sound description:

Well .. the best description would be.. you can hear music. The sound quality is as expected for one of the cheapest BlueTooth headphones around (with the exception of some Chinese crap found on Chinese websites etc.)
It lacks bass .. and treble. So all that remains is mids. Those mids are colored in several ways so it is hard to write an accurate description. Hollow and not very dynamic but fortunately not shrill or harsh sounding.
There is a substantial difference between the left and right channel so the ‘balance’ shifts from left to right depending on the present frequencies.

measurements

Below the frequency response of this headphone when connected using the 3.5mm TRS jack connection.FR.png
There is a substantial difference between the left and right cup. The driver matching is poor but given its price not surprising. The left channel is noticeably (5dB) louder on the left side skewing the balance to left.

 

Below alternating the frequency response (left channel only) between a wired connection and the BT connection.BT wired
There is a 3dB difference in loudness between the BT connection and headphone out of the Honor 9 mobile phone with the same volume setting. When wired it plays about 3dB louder and has slightly (2dB) more bass.

Seal

Closed headphones usually depend on a good seal (pads sealing off properly all around the ear) to get a good subbass response. This headphone is not different here. The seal will be highly dependant on the shape of the ear (Pinna) and whether or not hairs are covering the ear. As the pads aren’t really soft and compliant chances are there will hardly ever be a perfect seal. The ‘heard’ frequency response thus may be between sealed and seal broken.
Below the response measured (Right channel) with a perfect seal, seal just slightly broken, somewhat bigger gap, a few mm wide gap between the ear and pad. sealAs can be seen to get even some bass out of it a good seal is important. As there isn’t much bass anyway the actual impact on the sound quality isn’t that bad. A poorer seal just means it will sound even more ‘midrangy’

damping factor/output resistance (wired only)

A higher output resistance from an amplifier can affect the tonal balance of a headphone. This is dependant on the impedance of the driver as that can vary depending on frequency.
Below the effect of a 120Ω +output resistor is shown versus amplifier.120 Ohm 12.5dB
Aside from the loss in loudness there is no penalty to pay in sound quality.
The traces above are ‘overlayed’ so one can more easily spot tonal differences.
In reality the level was 12.5dB lower when driven from 120Ω.
In BlueTooth mode the ouptut resistance of the source thus doesn’t matter.

Below the distortion plot of the EE1178 (wired).dist RBelow the same plot but shown in percentage scale.dist R percentSmall drivers usually show an increase in distortion at lower frequencies. The EE1178 is no exception. Below 60Hz the 2nd harmonic distortion increases to 2%. This is not exceptionally high though at 90dB SPL (is not the same as 90 Phon).
Overall the distortion is decent at this price point.
The distortion in the mids may be below the shown 0.2% as this is the measurement limit of my measurement system.

There does seem to be something not quite right with the driver on the right side. Besides a difference in tonal balance and efficiency the distortion levels also differ… substantially. Below the distortion of the right channel (in percentage).dist L percent
The 2nd harmonic distortion reaches about 6%. Also the 3rd harmonic distortion is higher.

This made me check if all was O.K. inside and could see no differences. Below the rear side of the baffle and the front side. No porting anywhere. Most likely the differences between L and R come from the available space inside the cups being different because of electronics, battery, holes for buttons and 3.5mm jack.

Below the CSD (Waterfall plot) of the EE1178.
Right and Left channel are superimposed.CSDThe drop in higher frequencies is obvious. Also the frequencies that are reproduced seem to exist from resonances.

Below the step response with a dB scale (so not similar to an oscilloscope plot).  Left and Right channel over-layed.step
The slow rise after the initial impulse shows the lack of treble. After the rise the line should remain horizontal. The sooner it drops the less bass extension is there. This plot clearly shows the differences between the left and right driver.


conclusion

Quality products cost more money… This is by far the cheapest BlueTooth headphone I measured. And it shows. It is not a very comfortable headphone (despite its light weight).
The batteries won’t last a working day on a full charge and recharging them takes more time. Music won’t sound good but for making phone calls or listening to voices is decent.
The sound quality is conform its price … low.

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