James79 Posted October 29, 2013 Posted October 29, 2013 Hi there everyone, I have had a vaf SW4 sub for about 9 months to go with my DC-7s and a DC-6. It's a great sounding unit, very tight and musical. However, recently I've experienced a few problems with it. I've had no issues listening to music but when listening to films and TV series (mostly on bluray) occasionally I'll get a loud thumping or knocking sound coming from the sub. It of course freaks the hell out of me and straight away I turn the volume way down. What surprises me is that the loudest I've ever gone on the sub is two notches past halfway, with my Marantz SR5003 receiver at -25db. Thankfully there appears to be no damage to the sub, and it still sounds great afterwards. However, I've even experienced the same knocking sound with the volume exactly at halfway and my amp at around -30db. Admittedly, this only occurs when there are some serious low frequency sounds on the film - for example Robert Downey Junior rocking up to an event in a very growly sports car in Ironman. Correct me if I'm wrong, but I would've thought that the SW4 would be able to handle that kind of volume with no problems. I now listen at a couple of notches below halfway because I'm paranoid about doing permanent damage to the sub. I'm pretty sure I've got everything set up ok. Any advice or thoughts?
tubularbells Posted October 29, 2013 Posted October 29, 2013 (edited) Is your processor performing any additional EQ to the sub as that might be the issue. Also level matching or speaker mix down (eg. setting all speakers to "small") re-directing all bass to the sub could possibly be causing the signal overload. Also worthwhile checking the phase as if its incorrect you will find you have to turn the sub up higher to obtain correct bass levels. Edited October 29, 2013 by Tubularbells
James79 Posted October 29, 2013 Author Posted October 29, 2013 Cheers for the reply. I am using Audyssey on the Marantz. I have read a few articles about how Audyssey can try to boost the level of a sub at very low frequencies to try to keep the response flat, sometimes resulting in distortion. However, I've tested this by turning the Audyssey off, and the same problem persists although perhaps less frequently. All speakers are set to small and the crossover point I'm using is 80hz. This seems to be what most people recommend when setting up a sub, and it normally sounds pretty good to me. I'm pretty sure the phase is right. I adjusted this by listening to all the different positions and leaving it in the position that sounded loudest and bassiest. That happened to be all the way clockwise or turned to the right. I guess I'm just trying to find out if this is normal for the SW4 - that I really have hit its limits, or whether my unit has a problem. Surely one or two tiny notches above half way shouldn't kill it. It just bugs me because in normal scenes and for music it sounds great, but as soon as there are really low frequencies in films etc, I get the loud knocking sound again. I thought that normally the response of the sub would just fade out rather than the sub kill itself trying to output those frequencies at the same levels. Weird.
VAF Posted October 29, 2013 Posted October 29, 2013 Hi there everyone, I have had a vaf SW4 sub for about 9 months to go with my DC-7s and a DC-6. It's a great sounding unit, very tight and musical. However, recently I've experienced a few problems with it. I've had no issues listening to music but when listening to films and TV series (mostly on bluray) occasionally I'll get a loud thumping or knocking sound coming from the sub. It of course freaks the hell out of me and straight away I turn the volume way down. .....Any advice or thoughts? Hi James79, The more recent MPB SW4 has serious DSP compression management tech so what you are experiencing is not common. Just call us on our FreeCall number 1800 818 882 during SA office hours and we'll help figure it out. It'll likely be a set-up issue but let's go through the setup and check a couple of other things too, to make sure it's not a fault. There is a three year guarantee on VAF subs so don't worry, if there is a fault you are well inside that time period. Cheers, Philip 1
James79 Posted October 29, 2013 Author Posted October 29, 2013 Thanks for replying Philip, I'll give VAF a call in the next week or so. I'm in Adelaide as well which makes it easier. It could well be a set-up problem as I'm not exactly a pro. Would be great to get it sorted . LJT, the sub is connected via RCA.
VAF Posted October 30, 2013 Posted October 30, 2013 Thanks for replying Philip, I'll give VAF a call in the next week or so. I'm in Adelaide as well which makes it easier. It could well be a set-up problem as I'm not exactly a pro. Would be great to get it sorted . LJT, the sub is connected via RCA. Great. Look forward to the call.
wolster Posted October 30, 2013 Posted October 30, 2013 Dunno why you didn't call VAF in the first place. They are obviously more than willing to assist. At least you will now get it sorted.
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