Placing Components and/or Coaxials in Parallel => Any degraded Sound Quality?

Question is in the thread title, since I can't find a straight answer anywhere on the site here, or elsewhere on the internet.

The reason to put them in parallel would be to extract that 'extra' power from the channels by running 2 ohm loads. Are there any negative effects to sound quality?

 

Running the amp at 2ohms vs. 4 ohms will typically increase the amp's total harmonic distortion, BUT I doubt it will make an audible difference. Running at 2ohms also requires the amp to put out more current, which if the power supply isn't properly sized, could affect the transient (dynamic) response...again, probably not noticeable. Through a bunch of equations and math you could almost certainly prove that a 4ohm load is better sound quality-wise, but it's all about tradeoffs ($ vs. results) and whether those tradeoffs will actually affect your enjoyment. I say go for it. Extra power is never a bad thing.

 

It's been a while since I've been in this industry, so therefore I could be way off on this, but ever wonder why amplifiers and electronics talk about their low THD numbers, but you never see anything about THD on speakers?

I was always told that there was a reason for that... never explained explicitly, but for those with an ounce of logic in their head...

Again, I've been out of the game for a while (but I still love the stuff )

 

speaker distance to listening position, and sensitivity of the speakers will affect the performance of them if they are different brands/types.

 

Think about it....if your speakers are wired in parallel you'll lose the LEFT/RIGHT stereo imaging because you'll be listening to a mono output signal.

How much power do you have at a normal 4ohm load? I'm guessing it's plenty...

 

I wouldn't be giving up my stereo imaging - I would be giving up Front and Rear Fade: Take a 4 channel amp, bridge it into 2 channel mode. Wire your FR & RR in parallel, and FL & RL in parallel. So you have 1 big left channel and 1 big right channel. If its a high quality, old school amp, the power output more than doubles, and the amp is capable of handling the reduced load.

But from what I read above, a full range speaker's inherent deficiencies (from its materials and construction methods) also will become more audible. I also forgot about how the amp's THD sometimes exceeds 1% when you bridge channels or reduce the impedence, so that gets factored in the noise output. So I think my question's been answered - its not good to run a set of components or coaxials (full range speakers) in parallel because noise output may become audible.

I think with these new amps, the good manufacturers either figured out or decided to make available all the amp's available power without having to reduce the load. That Alpine PDX multichannel amp puts out 400 watt rms, and doesn't care if its in 4 channel mode or 2 channel mode, or the size of the load hanging off the channel.

 

Ahhh, ok. So a paralleled pair PER SIDE. Yes, that would allow you to keep stereo imaging.

I would urge you to, for the most part, ignore amplifier THD ratings. Not that they aren't accurate, but can you really hear .01% THD over the 3% THD your speakers are inherently throwing out? Speakers, since they have to move to reproduce sound, will ALWAYS be the weakest link in the signal chain...PERIOD. So until your system is to the point where your speakers are SO nice that you're fighting for that last .01% of clarity I'd tell you not to worry yourself over it.

However, I'd also tell you that you're not really going to get a ton of additional output via what you're attempting to do. You will gain 3db (theoretically) if your speakers can handle all the power.

This is likely the best time for me to ask you to explain your setup. What amp do you have and what components are you planning to use? What are your goals?

 

I am planning to go with the Alpine PDX series amps. The one is 100x4 and the other is 600x1 watt. Both are high quality sound stage output, and have frequency output which is beyond the normal 20hz to 20khz . I believe its 5 hz to 100khz. And all the noise generated from being a switching amp is supposedly designed to occur in the inaudible range. So i'm either planning to use that, or go the old school route and go with legacy amps from year 2000 Rockford Fosgate Punch amps - something of that vintage. Kicker ZR are awesome, but I wouldn't want to deal with tracking down those modules. If i went the old school route, I'd want to get all the power out of them.

My full range speakers: I'm reusing my Infinity Kappa 60.2cs (green cone) components in the front. These were powered by 50w rms each by an infinity kappa 54a amp a long time ago, and are still in perfect condition. For the rear I just got the refreshed infinity kappa 6.5 coaxials with the fiberglass cones and edge driven tweeters. These are fine in the rear and don't matter as much since the seats absorb so much of the sound.

I didn't want to, but I'm probably going to with that JL audio 13.5 sub for convienent box design ( i don't feel like chiseling the rear to make a normal high power handling sub fit, or using thin material), not to mention outstanding sound quality.

 

From what I recall, those PDX amps don't put any more power in 2ohms versus 4ohms. Also, they're not 2ohm stable when bridged. They are under-rated and will put out more power than their specs, so I think you will be fine running it in four channel mode to all four speakers. If you're wanting a little better listening experience, then I would ditch the rear speakers and bridge that amp to just your front speakers.

Those RF pump amps are tits and it would be cool to go the old school route. A friend of mine had a trio of them in his car back in the day. Two Boston Acoustics 12s and BA separates in the front with coaxes in the rear. It was a very dynamic system and stayed very clean at high volumes.

 

I didn't read every word in this post but what id recommend is this
1) 2 matching component sets and an amp that has a higher output at 2ohms that 4 ohms to take advantage of a 2ohm load per channel. Not many amps like 2ohm bridged either so i wouldn't suggest that. This suggestion is only valid if your wanting to put both component sets up front in the same door per side( 2x 6 1/2 , tweeter per door)

there wouldn't be anything wrong with this, but a properly setup 3 way active setup will most likely be a better option or a high end 2 way that can handle a bridged 4 channel amp.

I will say i am confused though, your bringing up THD and other factors but this seems to be a going loud setup. There is many other factors that would come into play before any decent amps THD limitations would become an issue

 

Well then.....I'd have told you not to waste money on coaxials for the rear and just spend more coin on the front speakers. That would have yielded way better sound. Especially if you bought something more efficient. You can double the power to a speaker to get an extra 3db of output OR you can just get a speaker that's inherently 3db more efficient. Both yield the same output.

 

Thats what I meant from my earlier post - for Alpine PDX amps you get all of the available rms power regardless of bridging or loading configuration. They are 20% underderated as well, (roughly 120 watt rms / channel based on Crutchfield and Amazon user reviews).

That series of classic RF and Kicker amps are basically from my high school and college years - they were so unaffordable back in the day. I still get that youthful, frank-the-tank feeling when I see them in person or see a picture of them. I don't really care for their new stuff or the specs (RF Punch and Power might be ok).

My Infinty Kappa 54a (50w x 4) and 202a (600w x 1) were very clean and ear-damaging loud - and apparently underated as well. Those were sold off and are long gone. I'm basically trying to replicate this system, but with even higher quality amplification.

 

Thats still an option - I could just run the rear off the HU deck, and cut off the low frequencies..and also reduce the rear output by 1 or 2 dB since my HU has that ability. I would just need to figure out where to mount another set of components in the front, and ideally find another set of what I currently have.

I don't totally agree with general speaker sensitivty ratings - if more energy is needed to drive a speaker, then its likely the speaker will have better materials and construction (bigger voice coil and magnet) in attempt to sound better and natural, prevent cone flexing and handle more power. The base level and mid level speakers usually have higher sensitivity because they are cheaper to produce and less costly to the customer, and also so they can run just from HU deck power. Either way, the speaker should be selected, subjectively, on the way it sounds, not the sensitivity rating. ( I am just speaking from what I have known from the past - I haven't checked any recent sensitivity ratings of currently available speakers).

This is a great audio conversation!

 

I don't design speakers, but I can tell you from experience that sensitivity is fairly independent of other parameters that make a speaker "sound good" (i.e., Fs, xmax, inductance, etc.). Because higher sensitivity makes more efficient use of the amplifier power, the resulting sound is perceived as more lively and dynamic.

Having recently gone from a subwoofer that was in low 90s dB sensitivity to something that is in the mid 80s dB, I'm having to apply more gain to get the same amount of output I previously had. Thankfully I have 1100 watts available for this single sub, otherwise I don't think I would have made the switch.

 

I agree with the bolded statement but not the ones that precede it. As a home audio speaker designer, I can tell you that higher sensitivity is a HUGE benefit and is one of the primary specs I look at when selecting drivers for a build. Sure, a cheap paper cone driver may have good sensitivity but ultimately sound like crap for a variety of reasons. But a sensitive driver designed with great materials is a force to be reckoned with.

Also remember, THD on an amp is typically measured at 1watt@1000hz I believe. So as power increases so does THD.....dramatically. So a more efficient speaker that doesn't require the amp to get into the higher realms of THD will have a competitive edge.