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Discussion Starter #1
Hi guys,

I have an Inphase IPX900 amp and an Inphase XT08R sub. Both were 'professionally' fitted at a car audio shop back in September. Last night I was driving home and I was playing a bassy track pretty loud (volume 13/14) on my stock head unit (it has hi to low convertor fitted) but no louder than normal. All of a sudden I lost bass and I thought maybe the kayak items I had in the boot moved and blocked the port on the enclosure but it hadn't.
So I pulled over to check it and the power lights are on the amp (including the protection light) so everything looks OK on the amp side of things.
Do I take it that the sub is the thing thats cooked? I'm suprised if it has as I'm running a lowly stock stereo and yet the sub has a power output of 1kw which far exceeds my head unit!
I am going to contact the shop today and hopefully take it back but there were numerous complications when I had it fitted so I'm not going to be a very welcomed customer:(:mad:.
 

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AO Silver Member, 155 Lounge Winner 09
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Could be, but there could be other causes for the problem:

1. cooked sub: if you gently push on the cone, it should freely/silently move in/out; if it's at all 'scratchy' (ie: burnt coil wire rubbing against magnet) that's a bad sign!
2. amp groundwire: could be loose or corroded; results in bad voltage drop to amp causing it to shut down
3. partly blown fuse: if using a cheap quality AGU/5AG style glass cylindrical fuse, the solder inside them melts away leaving a poor contact and poor power flow, even though the fuse wire remains intact; replace
4. bad connection elsewhere in power supply: check main powerwire connection to battery, wire to fuseholder, fuse, connections to amp
5. audio signal: could be a bad connection relating to the hi-lo converter or along that wiring

Should be easy enough for the store to work out.

:)
 
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Thanks shiny! Turns out it was option 1......a fried voice coil.

What I'm really frustrated with is the fact that the manufacturer does not warrant the failure of the voice coil. Now I can understand the reason why they don't warrant it as they don't want people blowing the things up with big amps etc. However, I'm running my standard head unit for heavens sake and theres no way that sub is getting anything like 1kw of power sent to it.

The shop explained to me that subs usually fail at this time of the year (winter over here) as the cold temperatures effect the movement of the rubber surround and it restricts the movement. Therefore the coil heats up and gets cooked. I fully appreciate that but it leaves me to foot the bill for another replacement driver which isn't cheap and it should never have failed in the first place with a standard head unit!
Even if I do get a replacement whats to say that won't go again and I will be in forever fear of turning it up in cold weather!

The shop are going to try their best to claim for me given the circumstances of what kit I'm running with but I don't hold out on much luck:(.
 
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Discussion Starter #4
I was researching the coil blowing in cold temperatures online last night and it appears that it isn't hugely common. I really therefore feel cheated that I've got this problem running on a stock stereo - its an absolute joke.
It does make me laugh to have the car audio sales people bang on at how rubbish the standard speakers in cars are, but having a decent sub blow in this way is hardly showing how much better their products are:rolleyes:. They were trying their damdest to sell me a new double din head unit and door speakers so I could unleash the power....well it would have blown even sooner if I went down this route.
Frankly, it seems that aftermarket subs are not fit for purpose as they are not designed for variable range in temperatures in cars.

Maybe BOSE stuff isn't so bad after all:rolleyes::lol:

Rant over:eek:.
 
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Discussion Starter #5
Hypathetically, if it turns out that its not under warranty and I decide to replace it, I could either buy the same or go for a JBL thats even cheaper.
The question is would the JBL sound as good and just as importantly, would it be more reliable (especially as the RMS rating is lower!). What are JBL like as a brand? Inphase are classed as high end budget....what about JBL?

In Phase XT8 1000 Watts Subwoofer - XT8 from In Phase


JBL GTO804
 
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Discussion Starter #7
OK got it fitted - bad news though - it doesn't sound a patch on the original. The original was thunderous resonanting bass that hung on for a lot lower and longer. This one has lots of bass but it just doesn't have the same quality feel to it....not surprising really when you consider the sheer size of the original magnet compared the pewny one I have now. I know size isn't everything but the results show this to be the case:(.

Oh well I guess I'll just put up with it seeing as though it is better than the standard stock setup. Gutted though:(.
 

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AO Silver Member, 155 Lounge Winner 09
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I was researching the coil blowing in cold temperatures online last night and it appears that it isn't hugely common.
Yeah, never heard this theory before as being significant.

I really therefore feel cheated that I've got this problem running on a stock stereo - its an absolute joke.
Unfortunately, it's not related to the stock headunit. It can happen with the stock or an aftermarket headunit.

The issue boils down to the sub being overpowered. This in turn relates to how the 'gain' on the amplifier was set. It was set too high, otherwise it would not overpower the sub. Whilst the gain should not be seen as a volume control (that's not the idea of the gain knob), it does alter how much power the amplifier will produce for the given volume setting on the headunit.

Honestly, it's the 'fault' of the installer/tuner. Given you had it installed professionally, they should have been more conservative and not set the gain so high; a lower setting would limit how much power the amp produced, to avoid overpowering the sub. I presume you did not alter the setting or instruct them to do so.

Most installers would not take the blame of course. But most would make the settings conservative enough to reduce the risk of frying the sub.

Whilst lower quality gear doesn't have the build quality of top quality gear, it still shouldn't fry when used and setup for its intended purpose, withint its intended limits.

OK got it fitted - bad news though - it doesn't sound a patch on the original. The original was thunderous resonanting bass that hung on for a lot lower and longer.
There are probably a number of factors at play here:
1. allow the sub to 'run-in'; over time, with normal use, it will loosen-up, and end up a little louder and 'lower'
2. subbox design: is the box optimal for the electromechanical (Thiele-Small) specs of the sub? Did the store model the specs and determine that your existing box (or whatever you have) is the right size, and right design (eg: sealed vs ported/vented)? If not, it'll sound like pooh; I'll see if I can find the specs to model and suggest a box design
3. low quality: I'm not familiar with that sub so can't really comment

I guess if you're still unhappy, you can talk to the store about changing subs again. However, if your description of their comments is all accurate (and not a misinterpretation, even if unintentional), they seem to be baulking at taking on responsibility and are trying to fob you off. Not great or honest service, IMO.

:)
 

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I can't find a Juice website, let alone the Qts, Vas, or Fs specs. Harks of cheap rubbish to me, unfortunatley.

Do you have the owner's manual, and does it state those specs?

:)
 
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Just what I thought by the looks of things shiny:(.

The place I got it from was caraudiocentre.com and they don't seem to sell anything other than Inphase really so I'm guessing I'm dealing with a bunch of amateurs. Trouble is there are not a lot of car audio places around full stop in the south east of england let alone in my neck of the woods.

I'll be honest here, I did tweak the settings a little while back (as in late September [I got it installed in Early Septmeber]) as it was too boomy and bassy for my liking so I made a note of the gain and superbass adjustments and turned the gain down and the superbass up.
When I originally got it I said I didn't want tons of bass like a boy racer, I wanted it to sound 'nice' similar to a BOSE setup.

My understanding of it was (and please forgive my poor level of knowledge here) that because my door speakers can only handle small power levels, the power of the amp powering the sub is also kicking out small power outputs. For example, say my door speakers are pumping out 30w RMS at volume 13/14 which is the most I'd ever have it up as, then my sub won't be kicking out 500w RMS because the sub would be massively drowning out the rest of the mid range and treble - the output of the sub might be more like 100w RMS. I always thought it was proportionate? With that in mind why would the sub blow at such low levels when it is designed for 500w RMS and 1kw peak?
Maybe the gain is still up too high but to be honest if it goes much lower then it seems to get lost....you just don't seem to get much effect as though its not even there.

I will let the sub run in (they recommend 40 hours) but I don't think it sounds as good as the original Inphase driver even taking into consideration its new - the magnet on the original is absoultey massive for a 8 inch cone and even the rubber surround is enormous.
The Juice just looks like a door speaker!!! Personally I think I've bought a load of tat! The Inphase stuff seems really good if a little feable, but the Juice just seems pants but I'll give it some time.

Haha with respect to the store comparing the different specs and type of enclosures.....forget it! They just said it was as good as the Inphase but I was doubtful and especially more concerned when they removed a hell of weighty sized sub and replaced it with something much more pewny looking. The just stuck it in. They know more than me obviously (or though I'm beginnning to wonder!) but I question their level of knowledge and competance.
Both subs had no manuals - only the amp did.

The couldn't sell me the original sub becuase they claimed it had been on back order for months. They did have a demo sub in store which the could have taken out but I was warey about a demo one and took their advice and got a new Juice one instead.
To be honest I have had it with these people....I have had so much (bad) history with them and although they have been friendly and helpful most of the time, I've lost my faith in them now.
I was thinking of just cutting my losses, pulling out the Juice and buying the original driver from somewhere else and fitting it myself. Trouble is I'm really unsure of whether the same thing will happen again. The amp is full of so many settings, subsonic filters, superbass, gain etc etc its all a bit confusing on what I should 'optimally' set everything as for best effect and protection and I have no expert to configure it locally for me:(.
 

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I'll be honest here, I did tweak the settings a little while back (as in late September [I got it installed in Early Septmeber]) as it was too boomy and bassy for my liking so I made a note of the gain and superbass adjustments and turned the gain down and the superbass up.
Depending upon how much you tweaked each settings, unlikely to be your fault in any way. Turning down the gain would reduce the overall power output (though towards max volume setting on the headunit the amp may still be producing more power than the sub could handle), though turning up the superbass will increase power at around that particular frequency. 'Bass boost' is usually centred around 45Hz, thereabouts. Something like a 6dB is quite a lot for example; that is the equivalent of 4x the power compared with 0dB/no boost. For example, with no bass boost, the amp might be producing 100WRMS at a given time; with +6dB boost, it would mean at 45Hz it would be producing 400WRMS. Every 3dB increase is double the power.

It is also possible to push the amp beyond its ability to produce 'normal' power, and go into 'clipping'. This is when the amp grossly distorts, and power output can suddenly rise. For example, if your amp is capable of producing up to 500WRMS, but you attempt to push it for more (ie: gain set too high and volume turned up too high), the amp will clip; the distorted signal can double in power quite quickly, and become a grossly distorted 1000WRMS signal, there-abouts, which would obviously overpower the sub. Mayb the amp was clipping.

My understanding of it was (and please forgive my poor level of knowledge here) that because my door speakers can only handle small power levels, the power of the amp powering the sub is also kicking out small power outputs. For example, say my door speakers are pumping out 30w RMS at volume 13/14 which is the most I'd ever have it up as, then my sub won't be kicking out 500w RMS because the sub would be massively drowning out the rest of the mid range and treble - the output of the sub might be more like 100w RMS.
That is fair; to achieve a nice balanced sound, a subwoofer would typically be using 2~4x the power of the speakers.

Just to clarify the terminology though, speakers and subwoofers consume power, but don't produce power. The amplifiers produce/provide the power; the speakers/subs consume it. When referring to loudness and the output of a speaker/sub, you need to talk about decibels, and not watts. :thumbs: So it's wrong to talk about speakers pumping out 30WRMS. :)

I was thinking of just cutting my losses, pulling out the Juice and buying the original driver from somewhere else and fitting it myself. Trouble is I'm really unsure of whether the same thing will happen again. The amp is full of so many settings, subsonic filters, superbass, gain etc etc its all a bit confusing on what I should 'optimally' set everything as for best effect and protection and I have no expert to configure it locally for me:(.
It may well be best to find another car audio store you're happier to deal with, even if you have to travel some way. Have them set you up properly from the outset, with a good quality sub and suitable subbox, and retune the amplifier within safe limits.

:)
 

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right... car audio center IS in phase, who also build Juice, the lower end stuff, and db audio, the higher end... I'm one of their sponsors...

yes they do sell other audio gear other than their own, but obviously, as I'm sure you would, they like to promote their own brand

In terms of your issue, the power going to the sub will be that of the amplifier not the h/u... for the ipx900 is 900rms or 1800 peak... the xt8 range iirc can take 800rms, at absolute full wack they may take more, depends on the type of box, frequency and a few other things, so firstly turn your gain down a little or it'll happen again

In phase, despite their previous ranges and build quality, have 'evolved' a LOT. In phase range are ow very good value, and they now have a 'Power Drive' Range which competes with top end subs like DC and orion. Back when DB house (in phase) first started out, they built 'cheap' stuff, because that what people wanted, over time the cheap stuff was put to their other name, Juice, and In Phase split into in phase, for mid range stuff, and DB audio, for high end kit.
Also ill point out that in phase/db audio/ car audio center are based and designed in the UK

So the Juice sub you have got now, yes it wont be as loud/good as the in phase one.

I have used in phase for over a year now and I give it some serious s***, and im amazed at how little failures I get, the subs have only ever failed on me once, and i was giving them almost double the recommended power input, and ive only had 2/3 out of at least 10 pairs I'm running of door speakers go on me. and the amps seem to be bomb proof
 
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Discussion Starter #13 (Edited)
Ah thanks! That explains an awful lot of things that were bouncing through my head about car audio centre and Inphase!

I'm frustrated in a way as originally I wanted the IPX 600 amp as I had a feeling that the IPX 900 might be pushing the boundary for the XTB08R but the salesman insisted on me getting the more powerful model. But hey ho I'm not going to rant on about the service I got....after all they are to sell although I don't like the sales attitude of going over and above what you need just for the sake of it. Still the past is the past.

Speaking more productively, are you able to tell me if the XT8 is the same as the XT08 driver thats fitted into to the XTB08R complete sub? I only ask as I'm going to ditch the Juice as quite frankly it really sounds pants...the Inphase on the other hand sounded great until it went pop! I see the visual difference is the XT8's have a polished rear so they can be inverted for show use but what about the quality of the magnet etc? is that the same as what I had in the XTB08R?

The funny thing was, it never sounded anything like a 1kw of power coming from the sub....I have a 1kw home cinema system and thats seriously loud! With the car doors closed, it seemed pretty well much the power levels of what my 147 BOSE had, albeit with a much deeper rumble.

I will turn down the gain though when I get the new driver and will seek to get it tuned from someone who has a good idea what levels it should be pushing out!
 
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Right! I purchased another XT8 sub and have just fitted it. Thankfully it sounds great just like the old one! That Juice one really is a total piece of junk - what a waste of money that was......hey ho.

I haven't yet turned down the gain as I want to have a proper play around with the settings properly when its daylight. I will eventually take it to someone to get tuned just to make sure but in the mean time the volume will be a bit below what I had it up before it blew:rolleyes:.

Shiny! I have the specs of the XT8 for you that I just got....beleive it or not they display it when you buy a sub driver but not the whole thing:rolleyes::rolleyes:.

Here it is:

Model: XT8
Woofer size: 8 inches
Nom. Imed (ohm): 4
FS (Hz): 38
RE (Ohm): 3.6
LE (mH): 0.82
QMS: 6.11
QES: 0.51
QTS: 0.46
VAS (cu.ft): 0.41
VAS (liter): 11.68
Power (Watts RMS): 500
Power (watts peak): 1000
SPL ([email protected]/1m): 86
X-MAX (inches): 0.20
X-MAX (mm): 5.1
F3 (Hz): 45 40
Sealed box (ft3): 0.4 0.6
F3 (Hz): 35
Vented box (ft3): 0.5
Mntg.Dia (in): 7 3/10
Mntg.Depth (in): 4 1/2

Your honest opinion shiny on the specs????;)
 

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The specs look ok. The cone excursion (x-max) is not big, but not bad. I would go with a sealed box for a sub like this, because it would reach max excursion more easily in a ported/vented box.

Modelling the specs, it would be good in a sealed box around 0.3~0.5cuft in size. That's nice and small.

:)
 
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Discussion Starter #16
Ideally what would be nice would be to have two seperate ones of them in custom sealed enclosures in the corners of the boot, behind the rear light clusters - but then again I'm not good with fireglass!

To be honest I'm just happy I have my great little sounding sub back again so this afternoon I will turn down that gain!
Apparently you are suppose to have the controls right down on the amp and you need to turn the HU up to how you listen to it and then dial in the gain.....but how do you know when it is set to the correct level?
 

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You can never be sure that you're not overpowering the sub (not without say a cathode ray oscilloscope to measure the power output). However, it's unlikely you'll need much power before it out-doofs the speakers. If you hear distortion, then you're definitely over-doing it.

I think it's fair advice, to start with the gain at minimum, then dial it up to level-match with the speakers (ie: blend in nicely without being too soft or loud in comparison).

:)
 
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OK thanks again shiny. On Sunday I took the car out into a quiet spot in the countryside and turned up the volume and progressively dialed in the gain. The gain is now around 50-60% (was almost 100% previous) and the superbass is about 90% (I never like running bass gains at 100% as it always seems to distort itself).

Hopefully this should drastically improve the longevity this time:thumbs:. It still sounds really fruity too so I'm happy as larry once again:).
 
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