Hi everyone,

Just wondering what amp you would use for the above combo?

I'd prefer to keep it to a single amp if possible.

Also, should I go with a 10" or 12" G5 with these speakers? I want a nice flow to the system, quality, not massive, out of proportion bass.
Sub will be dual 4 Ohm.

Top of my list so far is an Audison LRX 4.1k
Rating is 130WRMS x 2 @ 4 Ohm + 800WMRS x 1 @ 2 Ohm

What else should I consider? Budget is about $1500 max.

Never listened to the Iridiums, but if there anything like my Nobeliums, then they want loads and loads of power to sound their best.

Mine are currently getting 350rms each side. Ive had up to 600rms running into them, and they didnt mind one bit

With these Audison amps, I've notice the damping factor is only about 100-120. Isn't this a bit low? Especially since the rating is for 4 Ohm. At 2 Ohm, that would make a damping factor of 50-60 which I think is low enough to make an audible difference to the quality of a dual 4 ohm G5?

Should I switch to a single 4 Ohm G5 instead for better sub control?

The Audison LRx 5.1K is a good quality amp and puts out plenty of juice.

I'd look at DLS Reference, Helix Competition series (if you dont mind getting them brought in from overseas) and Focal. Three nice options



Doesn't really matter much. 10" means lower sensitivity, which means you'll need more power to get it to keep up with the front stage. Boston subs aren't typically especially efficient to begin with, so depending on how much power you have available that may be a factor.

I'd go the 12" personally. Even if you have a lot of power available, higher efficiency means less power is needed to run it, which means you are putting less strain onto both the sub (less excursion) and the amp (lower gains).

In the case of a highish sensitivity 10" (say, an previous model IDQ, for example) this isn't a big deal, but I think the G510 has a lowish sensitivity around the 85db mark (if my humble memory serves me right). That means compared to an 88dB sensitivity sub, you'll need roughly double the power input to reach the same output level.

Im one of the few to have tried the DLS refrence against the new Audison LRx, and, I would say, I would pick the DLS over the Audison by a fraction for sound quality, and a decent margin for build quality.

The Helix amps, as Muzzy have a fantastic reputation as being on of the best bang for buck amp brands. The Focal amps are a good unit, as too are the Audiosystem range if you want to spend a little less.

I also echo Muzzys comment about the sub. The 12 will probably be the better option, unless you have space constraints. Then I would also pick a 10 in the right sized box, over a 12 in a box to small to suit the sub specs, and car environment.

Have you considered going active, or are you staying passive for the splits. The DLS crossovers are a fairly good, very heavy unit which appears to be of quality. The stock crossover point is 3,800 hz if I remember correctly, which works with these tweeters. If I was going active, I would probably go with a 3,200hz crossover point, on a 24db slope. It will depend on the car, but, Ive had some experience with these tweeters, and know that a 24db slope tends to work the best, and I wouldnt really crossover them over much below 3,200 as distortion tends to be to great when a decent volume level is pumped through them.

Assuming your amp budget was $1500, and you were running passive, I would suggest the DLS RA20, and probably an Audiosystem amp for your sub. If you wanted to stretch your budget out a little bit to $2,000, Fhrx has some ex demo DLS ultimate amps for sale. The monoblock, and the large two channel. The DLS ultimate amps are ment to be right up there with some of the best car amps in the world.

Would you care to point out where we were lacking in build quality?
The world's press, EISA and the CES organisation would seem to be at odds with your opinion.

Helix Competition amps would be awesome, not sure if pricing is within budget though.

Active set up with the A6 for fronts - 2x 75 for tweeters, then 2x 220 bridged for mids?

Or just keep it simple and go the A2 at 2x120 for passive front?

Probably throw in another A1 or A2 for the Sub.


I'm thinking about changing subs too... Maybe to a Focal 27 KX


So many choices, I don't know which way to go.

He didn't say the LRx isn't well built, he just said that in his opinion the DLS is better built.

I haven't compared the two amps internally, but based on 'external build quality' I'd have to come to the same conclusion. Nothing wrong with the LRx, but the DLS just has a slightly more impressive overall look and feel to it. It's hard to explain in detail without having one of each in front of me, but the Reference just looks and feels that little bit more 'tank like' in build, and the small visual touches like the alloy look and gold knobs/connections etc give it a more elegant (imo) look.




If you have the room, I'd go active for sure with the 6 channel if you can get a hold of them. I'd buy one myself, but the A6 is a pretty big amp, and I'm not sure if it will fit in the space I plan to put it in.

Standard passive will get beaten by a (well tuned and installed) active pretty much every time.

for $1500 budget on a 4 ch i would go a amp that has bandpass crossovers, it has resale , it has options for any type of system integration.There are many amp brands that will do it but one amp brand i know off is the hertz high end range.

yeah dont think to hard about amps .

low dampening factor isnt always a bad thing

Yes, didnt say the amp was bad built. I said it wasnt as good as the DLS.

If you were in Sydney I would be more than happy to take an afternoon, and show you the areas where I thought the LRX series of amps lack in the "external" build quality area.

I mention external, as I have never pulled the covers off any amp, and cant comment on the internal (more important ?) build quality side of things.

Ok, I can get a Helix A6 for a little over $1000. I'm considering using this for the whole set up.

4x 85WRMS for the fronts active, and 1x 400WRMS for the sub, possibly a focal 27KX.

This way I can upgrade later with an additional amp for the sub and run the woofers bridged at 220WRMSx2.

Does this sound like a good option. Should be enough power to keep me happy for now, and has the potential to be upgraded without waste down the track if I decide I need more.

Damn right it sounds like a good option!!

Personally, I'd go with Helix over any locally available amp with the exception of possibly Sinfoni (which is much, much more expensive). Helix is essentially a 'budget Brax'. They both come out of Audiotec Fisher and to my understanding are built by the same people. One thing for sure is that both are built to a very high standard using great quality components and both a reputation for stunningly accurate presentation. My previous amp was a Bras, and it was (by a mile) the best amplifer I have ever used. Build quality, sound quality and reliability were all absolutlely fautless - all you need to do is pick up a Brax and you are immediately convinced of it's quality. Given the Helix's claimed frequency response of +/-0.3dB from 20hz - 20khz, and stunningly impressive on-paper specs I'd be wiling to bet the Helix probably sounds just as good, but just with less power and slightly less 'tank like' construction.

I wouldn't mind one myself to be honest. At this stage my prefrence is DLS Reference due to it being smaller and more easilly available, but if I'm able to get a Helix without too much trouble then size is probably less a factor...I'll make it fit!!

I'd be interested to know where / how you would be getting it. Any chance you could PM me with some of the details?