You are not logged in. [Log In]


Forums » General Discussion » What's New At Axiom » LFRs Improve Your Image

Page 2 of 4 < 1 2 3 4 >
Topic Options
Rate This Topic
#425373 - 05/03/17 06:46 PM Re: LFRs Improve Your Image [Re: Ian]
cb919 Offline
connoisseur

Registered: 02/17/09
Posts: 1169
Loc: Ottawa, Canada
That's too funny. My wife actually does want an addition on the house - now I'll have to make LFR's part of the deal if we ever do it! laugh
_________________________
Dan
On-Wall M5HP LCR, QS8 & EP500 in 7.1

Top
#425378 - 05/04/17 08:57 AM Re: LFRs Improve Your Image [Re: Ian]
ebZCXc Offline
newbie

Registered: 05/04/17
Posts: 2
I'm a new poster here but have had great axiom products for years. My lfr 660s have provided me with 2 years of music bliss. Ian is right about the sound stage, I can move around on my couch anywhere and nothing changes. Beore my lfrs if I moved 6 inches things started to get out of whack. My lfrs are the best!

Top
#425379 - 05/04/17 09:11 AM Re: LFRs Improve Your Image [Re: Ian]
ebZCXc Offline
newbie

Registered: 05/04/17
Posts: 2
Sorry about my name being ebZCXxc as this was my verification code. One of these days I'll have to change it to southguy. I guess this proves I am a very very newbie to all of this!

Top
#425469 - 05/08/17 01:35 AM Re: LFRs Improve Your Image [Re: bridgman]
bridgman Offline
axiomite

Registered: 08/25/04
Posts: 6205
Loc: Bowmanville, Ontario, Canada
Originally Posted By bridgman
IIRC you mentioned building DSP into an amp before, although I think it was the -1000 and LFR's seem like a better match with 1500's unless they are a solid 4 ohms in the important regions, which I don't think is the case.

Whoops, my bad. They are "a solid 4 ohms in the important regions" so a single -1000 amp should be able to deliver 4x250W.

OK, so now I understand where the ADA-1000 fits.

Hmm...

I was poking around looking at LFR1100 options and noticed that (a) once you select high power woofers the cost difference between LFR880 and 1100 is pretty reasonable and (b) the additional cost for adding an ADA-1000 integrated with the DSP is *really* attractive already.

Trade-up on the M60s and M3s looks decent... if I was smart I would add the M5HPs to the trade-up list as well but I *really* like them (even better than M60v4's)... they're in "from my cold dead hands" territory right now.

Hmm...


Edited by bridgman (05/08/17 02:02 AM)
_________________________
M60ti, VP180, QS8, M2ti
M5HP, M40
LFR1100, soon to be active
EP500, PC+ 20-39

Top
#425472 - 05/08/17 09:19 AM Re: LFRs Improve Your Image [Re: Ian]
MatManhasgone Offline
connoisseur

Registered: 05/06/14
Posts: 1049
Loc: Lost in the great wide yonder
The amplification power requirements for the LFR's are sort of out there. The front set of speakers are a 3way and are rated at 4ohms. The back set of speakers however are only 2way and actually i was told from Andrew that they come in at 8ohms.

Effectively then with the ADA1000 you are getting 2x250+2x125 for power.

To throw more confusion into the big picture, the rear channels do not nearly as much sound volume as the fronts do. I own a set and know that if I pull the connectors from the front speakers so i am only driving the rear set, the amount of sound drops to a fraction of loudness. So the rear speakers are not producing the exact same sound as the front. This is the beauty of the DSP in it does do magic filtering to make the reflected sound fill in what you are wanting to hear when standing in the front of the speakers.

So that known, you really are not using anywhere near the 125w of power available for the rear drivers as is given by the ADA1000. Though looking at the design spec for the ADA1000, there is no difference in max power output driving just 2 speakers at 4ohms vs 4 speakers. The question to ask is what sort of effect does having the DSP driving rear speakers have with the larger ADA1250 or ADA1500? I have yet to get an answer though I have tried to ask many times
_________________________
Anthem: AVM60
Axiom: ADA1000, LFR1100, VP180, QS8, EP500, M3, M3comp
AudioSource: Amp One/A

Top
#425473 - 05/08/17 11:59 AM Re: LFRs Improve Your Image [Re: Ian]
bridgman Offline
axiomite

Registered: 08/25/04
Posts: 6205
Loc: Bowmanville, Ontario, Canada
We need to get someone to take away Ian's pair of 1500-2's, replace them with a single 1500-4, and see what happens smile
_________________________
M60ti, VP180, QS8, M2ti
M5HP, M40
LFR1100, soon to be active
EP500, PC+ 20-39

Top
#425479 - 05/08/17 06:30 PM Re: LFRs Improve Your Image [Re: MatManhasgone]
Ian Offline
President
connoisseur

Registered: 03/13/01
Posts: 1289
The world of power requirements for audio reproduction can be a bit confusing. I think the main reason for this is the use of the continuous RMS power output as the benchmark measurement (not that I necessarily have a better one mind you). But for audio what is important is the peak power available for the dynamics not the continuous RMS output. The dynamic power available is determined by three factors; the continuous RMS output capability, the size of the power supply, and the amount of capacitance storage available. With a big power supply and lots of capacitance storage you can safely use a factor of 3 times the continuous RMS output as a good number available for dynamic output (this multiplier could be higher as the impedance of the speaker rises above 4 ohms). Keep in mind that for virtually all receivers and even some big power amps the multiplier for dynamic power is likely only 1 or just slightly more than 1. Consider you want 15dB of available head room for dynamics. This means you will need 32 times the continuous power to achieve it. So it we use the ADA1500 as an example we would have around 2,000 watts available for dynamics (650 x 3). Dividing this by 32 gives us 62.5 watts continuous. So we don’t need the 650 continuous watts available in the ADA1500 for our continuous power requirement, but to have a high enough peak power to allow for listening at 62.5 watts continuous. The last piece of the puzzle is how many channels the power supply can drive to full power at the same time. Once you cross this line both your continuous and peak power will start to drop per channel if all channels require the max all at the same time.
_________________________
Ian Colquhoun
President & Chief Engineer

Top
#425483 - 05/08/17 09:30 PM Re: LFRs Improve Your Image [Re: Ian]
MatManhasgone Offline
connoisseur

Registered: 05/06/14
Posts: 1049
Loc: Lost in the great wide yonder
Originally Posted By Ian
Once you cross this line both your continuous and peak power will start to drop per channel if all channels require the max all at the same time.


It's that last sentence that really sums it all up. And this is where we need the guidance as you are using the 4 channels of the amp to drive 2 speakers.

Now if you were bi-amping this were one amp channel was being used to drive the large woofer set, and the second channel was getting used to drive the smaller mids and tweeters, you likely would be saying the power pull on the channel driving the woofers would be much higher than that of the mids/tweeters as those drivers have a much bigger coil and far more displacement moving a larger mass cone.

Can the same be said for the rear set of drivers on the LFR? So in essence, the ADA1500 will likely be getting a dynamic output closer to 2000w than the 1050w (350x3) if you were driving a full range speaker on each channel instead of the DSP driven rear LFR channel.

Hypothetically of corse .. not trying to back you into a corner and committing to something that has too many variables to quantify exactly.

I am looking at it from the side that the ADA1000 in reality gives you an upper limit of 750w.
_________________________
Anthem: AVM60
Axiom: ADA1000, LFR1100, VP180, QS8, EP500, M3, M3comp
AudioSource: Amp One/A

Top
#425486 - 05/08/17 09:58 PM Re: LFRs Improve Your Image [Re: Ian]
Gr8_White_North Offline
connoisseur

Registered: 07/12/09
Posts: 2281
Loc: Whitehorse YT
My question is why more capacitance is not used in amplifiers , is this a space restriction issue or is there a limit to the effectiveness. On my sub in my car i have a large capacitor since lead acid batteries do not like to release huge amount of current . It also keep my headlight from flashing smile
_________________________
DOG is GOD spelled backwards.
What others think of me is none of my business.
M80 V3 MY GLOSS Cherry

Top
#425495 - 05/10/17 01:31 PM Re: LFRs Improve Your Image [Re: Gr8_White_North]
Ian Offline
President
connoisseur

Registered: 03/13/01
Posts: 1289
I will start by answering Socketman. The amount of capacitance should be a balance decided by the amp designer. At some point increasing the capacitance further will mean you should also be increasing the continuous power output of the amp modules and the power supply that go with that increased capacitance. The flip side is reducing the capacitance; this can be an easy way to save a lot of money in the cost of the amp without reducing your continuous RMS power specification; this has the appearance of more watts for the dollar.

Matt is entering the area of multiple amp power management to get the biggest bang for the buck. The impedance curve is helpful in figuring this out. You can take an educated guess from a single impedance curve but if you can get separate impedance curves for the woofer section and the mid/tweeter section even better. The phase is also a factor here but let us leave that out for now. As the impedance rises the current demand to achieve the same SPL is reduced (assuming linear amplitude response from the speaker). Since the standard impedance curve rises with frequency it follows that it requires less power from the amp to drive these higher frequencies. So if you own more than one amp with the same gain but different power levels you should drive the mid/tweeter section with the smaller amp; or in the case of an LFR, drive the rear channels with the smaller amp. You can get a quick answer to what the amp differences should be by just dividing the higher impedance by the lower impedance. So if the rear of the LFRs are running around 10 ohms and the front around 4 ohms you would need 2.5 times the power to the front (10/4). An ADA1000 for the rear at 250 watts and an ADA1500 for the front at 650 watts works out pretty well.
_________________________
Ian Colquhoun
President & Chief Engineer

Top
Page 2 of 4 < 1 2 3 4 >

Moderator:  alan, Andrew, Brent, Debbie, Ian, Jc 
Forum Stats

15,326 Registered Members
16 Forums
24,174 Topics
427,322 Posts

Most users ever online:
883 @ 03/04/17 05:06 PM

Top Posters
Ken.C 18044
pmbuko 16437
SirQuack 13608
CV 11734
MarkSJohnson 11445
1 registered (Mojo)
208 Guests and
0 Spiders online.
Key: Admin, Global Mod, Mod
Newsletter Signup