There are several reasons why your surround speakers sound muffled, particularly on the high frequencies. But this can also occur in the mids like dialogue in movies.
Here are a few of the reasons why your speakers sound muffled:
- Faulty audio gear
- Overdriving your amplifier
- Faulty speaker wiring, particularly not matching polarity
- Wrong speaker placement
- Pushing your speakers too hard
- A bad source with unclear audio
This can cause your high or mids to sound muddy as if they are coming from a closed box.
Based on the cause of the muffled sound, you can find an easy fix, expensive fix, or be forced to replace some of your faulty gear. Either way, you need to troubleshoot the cause of the muffled audio first before proceeding to a viable fix for each of the causes.
So, let’s check out the reasons why your surround speakers sound muffled before delving into how to fix them.
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1. Pushing Your Speakers Over the Limit
Different speakers have different power ratings based on the manufacturer and the cost.
A good example is a speaker with a rating of 100 watts. These speakers can reproduce the sound while being operated at 100 watts continuously for some time. However, they can also be driven at higher watts, like 300 watts, over a shorter period, normally a few milliseconds.
Therefore, if you are operating the speakers at the optimal power rating or exceeding the speakers’ power rating, the speakers may not reproduce some of the audio signals, consequently producing a muffled sound.
To fix this or prevent it from happening, you need to know how much power your speakers can handle. Then you can lower the volume on your receiver or amp to reduce the amount of power they output to the speakers.
If you can still hear muffled sound coming from your speakers, particularly in the dialogue, increase the level on the center channel by around 2 decibels or try re-calibrating the while sound system for the correct levels and crossover frequencies.
Using incorrectly calibrated receiver/pre/pro as per your speakers can reproduce a muffled sound and greatly affect the overall sound quality.
2. Bad Audio Sources
If you have a bad audio source, it can muffle the surround sound in your home theatre, decreasing the overall experience of enjoying music from your home theatre.
Your soundbar, audio processor, or TV may not be able to clean the unclear audio from a low-quality source. Nonetheless, you can easily troubleshoot this by changing between various sources.
You can try playing a higher-quality video or film. Also, you can play it using a different device. If the muffling disappears, you will need high-quality sources with a better and clearer audio quality.
Nonetheless, if the problem does not originate from your source, you can continue troubleshooting.
3. Wrong Speaker Placement
Several people make the common mistake of placing their speakers inside a cabinet or enclosure. This may obstruct sound waves, causing reverberation and muffling within.
Correct placement of your speakers and positioning them in an open space where the sound waves can travel unhindered will easily fix muffled sound problems.
Additionally, if you want to position your speakers behind your projector screen, ensure the screen is made of an acoustically transparent screen.
Also, if you want to place your speakers in-wall for a cleaner set-up, ensure that the speakers are in-wall rated. You will greatly affect the sound quality if you use a speaker that is not in-wall rated – and a muffled sound will be a sign of this.
4. Overdriving Your Amplifier
Like in speakers, receiver/integrated amps and amps have different power ratings, which is the amount of power they can output per channel.
Sadly, power rating specs can be outright deceitful or inaccurate. This is done intentionally by a few manufacturers to make their equipment appear more powerful than they are. Also, this may result from the manufacturers measuring the power rating in perfect rooms with ideal conditions.
This may cause some consumers to crank up their amplifiers over the limit, which ends up producing a muffled surround sound.
Most amplifiers can output around 70% of their specified power rating without causing distortion or noises such as muffling. This implies that if your amp/integrated/receiver is rated at 120 watts per channel, running it at around 75 to 85 watts per channel would be best.
Additionally, you need to remember that 120 watts may be good for your subwoofer if you have one. Nonetheless, your tweeters or mid-range speakers won’t need 120 watts.
5. Faulty Wiring During Installation
It is not uncommon for people to wrongly wire their speakers during installation. A common mistake is reversing the polarity.
A reversed polarity happens when you connect the amp’s negative terminal to the positive terminal and vice versa. When you do this, some of the lower and mid-range frequencies may be canceled out, and as a result, the speakers may produce a muffled sound or other anomalies.
Another common connection mistake is failing to match the speakers’ impedance to the receiver or amp. The impedance on both the amp/receiver and the speakers has to match.
Nonetheless, you can match the impedance of your speakers to the amp by connecting the speakers in series. An example is a speaker with an impedance rating of 4 ohms is connected to an amp with an impedance rating of 8 ohms. When you connect two of these speakers in series, you get an 8-ohms impedance rating.
Some integrated amps and receivers may have an impedance switch where you can toggle between 4 and 8 ohms to match your equipment’s impedance.
6. Faulty Audio Gear
Both your speakers and amp can have defective parts which may need replacement. Nonetheless, most faults occur on the speakers because of being overpowered.
If you have multi-way speakers, you can play an audio clip at a low volume and then listen to each speaker beginning from the tweeter, the midrange, and the woofer.
Each speaker has to reproduce a certain frequency, and you need to be able to tell if either of the speakers is working or not working at all.
Here are common speaker defects that may cause muffling of the sound:
- Faulty crossovers and capacitors: You can figure out your crossover is damaged if the sound has been deteriorating over time, leading to a muffled sound. The crossover can blow over time and completely get damaged, needing replacement.
The capacitors on the crossover may also be damaged. You can easily tell if they have changed shape, caps with brown crusts, leaked electrolytes, or are completely blown. These capacitors are not able to retain voltage, and a recap may be needed.
- Blowing of the speaker due to overheating and over-excursion: To confirm if your speakers are blown, you need to remove the grill to check if the foam around the cone has deteriorated or if the speaker has been ripped from the speaker coil. The speaker coil may also burn to form a sticky substance around the coil.
Based on the extent of the damage, only one part of the equipment may need replacement, or you may need to purchase new gear.
With these fixing and troubleshooting steps, you should be able to get rid of the muffled sound by yourself either by purchasing new equipment, getting a simple fix, or getting any damaged gear checked out and fixed by a professional.