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Discussion Starter · #1 ·
EDIT: It's 1.5" more woofer!


For my dorm room I'm trying to decide between a pair of Primus P152s and P162s.


The P162s play louder (90db eff vs. 88db) and play deeper (6.5" woofer vs 5").


ON THE OTHER HAND they are quite a bit bigger (2" taller, 1" wider) and the 152 is already pretty big.


Given that I will have a sub, will the P162s give me much more than the P152s? I'd like to go with the smaller speakers if that means very little compromise in sound.
 

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Strictly from a mathematical point of view, it increases the projected surface area of your woofer by over 69%. I'm no audio engineer, but I would guess that it has a noticeable effect on the output.


Does it make sense to make the jump for your situation? That's probably question for somebody more experienced than me. I would probably stick to the smaller one for a dorm room, but it may be worth it for you.


(edit for diameter change to 5")
 

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The larger driver has over 69% the surface area. Does this seem like something that can make a difference?


EDIT: 5.25" -> 6" >50% increase in area; 5" -> 6.5" > 69%. So what JamesBob02 said (Good math skills. Being a student, enwar3 should have figured that out, too)
 

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Quote:
Originally Posted by enwar3 /forum/post/14208031


Given that I will have a sub, will the P162s give me much more than the P152s? I'd like to go with the smaller speakers if that means very little compromise in sound.

It would be a minimal difference.
 

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Discussion Starter · #5 ·
Well I mean I figured it'd be significantly larger in terms of area, but I was interested in terms of practical audible difference. I'm stumped because


1. The main difference between the 162s and 152s is bass extension, but wouldn't this be a moot point if I have a sub?


2. Also, the 162 is slightly more efficient (90 vs 88).. does this translate into any real world difference in volume? I'm running an 85wpc Yamaha (105wpc 1khz).


3. This thought just came up. The 162s handle a max 150W whereas the 152s handle 100W- does that mean with my setup the 162s would start clipping before the 152s? In this case, which pair of speakers could play louder before distorting?


EDIT: I'd like to get the 152s because they're smaller, but I don't want to sacrifice audio quality (50/50 movies/music). But the question is: how much audio quality do you lose?
 

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Strictly answering your questions:


1. You'd think so, but, no, it's not a moot point. In actual measurements bass on the smaller Primus start rolling off around 100 Hz (regardless of the claimed 58Hz - 20,000Hz) below that port tuning helps it a bit to about 80, and then it's all but gone.


2. Each additional 3 dB of SPL requires doubling the input power, so at every given volume the 152 will be using 1 2/3 more power than the 162s, which brings to...


3. While 152's cannot handle as much power as the 162's, because of their lower efficiency your amp will begin clipping sooner connected to the smaller of the two


NOW, you want my sincere advice? Take the smaller Primus 152 and enjoy the extra $50 in your pocket - maybe buy your girlfriend something nice.

EDIT: I think I left you confused with my last line.

In a small dorm room (I remember from my college days the rooms were VERY small, and I doubt they've grown much) you'll be listening from only a few feet away using maaaybe 2W/ch from your Yamaha. The 5" drivers tend to be more musical than the larger ones, so you'll likely have cleaner sound from them, too, but still enough punch for movies and dynamic music passages.
 

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Discussion Starter · #7 ·

Quote:
Originally Posted by vinipux77 /forum/post/14208636


Strictly answering your questions:


1. You'd think so, but, no, it's not a moot point. In actual measurements bass on the smaller Primus start rolling off around 100 Hz (regardless of the claimed 58Hz - 20,000Hz) below that port tuning helps it a bit to about 80, and then it's all but gone.


2. Each additional 3 dB of SPL requires doubling the input power, so at every given volume the 152 will be using 1 2/3 more power than the 162s, which brings to...


3. While 152's cannot handle as much power as the 162's, because of their lower efficiency your amp will begin clipping sooner connected to the smaller of the two


NOW, you want my sincere advice? Take the smaller Primus 152 and enjoy the extra $50 in your pocket - maybe buy your girlfriend something nice.

EDIT: I think I left you confused with my last line.

In a small dorm room (I remember from my college days the rooms were VERY small, and I doubt they've grown much) you'll be listening from only a few feet away using maaaybe 2W/ch from your Yamaha. The 5" drivers tend to be more musical than the larger ones, so you'll likely have cleaner sound from them, too, but still enough punch for movies and dynamic music passages.

Thanks so far vinipux... that was really helpful!


I don't quite understand why the smaller Primuses will start clipping first-- if I understand you correctly, you're saying that they take more power to hit the same decibel level and that's why they'll start clipping first, right?


And if the smaller speakers roll off around 100hz, won't that make music listening a little weird due to the silent gap? Or will the bigger speakers not do much better?


Also, I won't really have these on my desk next to my computer anything. I'll probably have it next to the tv in the common room, viewing distance about 6 feet? What do you think, in these conditions?
 

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Quote:
Originally Posted by enwar3 /forum/post/14208762


Thanks so far vinipux... that was really helpful!


I don't quite understand why the smaller Primuses will start clipping first-- if I understand you correctly, you're saying that they take more power to hit the same decibel level and that's why they'll start clipping first, right?


And if the smaller speakers roll off around 100hz, won't that make music listening a little weird due to the silent gap? Or will the bigger speakers not do much better?


Also, I won't really have these on my desk next to my computer anything. I'll probably have it next to the tv in the common room, viewing distance about 6 feet? What do you think, in these conditions?

The more efficient the less power required to be as loud and 2db will lighten

the load on receiver but at 6ft i would go for more efficient.
 

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Quote:
Originally Posted by enwar3 /forum/post/14208762


I don't quite understand why the smaller Primuses will start clipping first-- if I understand you correctly, you're saying that they take more power to hit the same decibel level and that's why they'll start clipping first, right?

Correct, except "clipping" applies to the amp, and what you hear immediately before it becomes dangerous (sometimes still too late) is distortion from your speakers.
Quote:
And if the smaller speakers roll off around 100hz, won't that make music listening a little weird due to the silent gap? Or will the bigger speakers not do much better?

It's not what I meant to say, if you cross over at 80Hz, assuming the sub can pick up well after that, there's no gap. When Stereophile tested the 150's they actually noted how well the port was tuned in respect to the main driver, which really helps extending the output essentially flat to 80 Hz with a sharp rolloff thereafter.
Quote:
Also, I won't really have these on my desk next to my computer anything. I'll probably have it next to the tv in the common room, viewing distance about 6 feet? What do you think, in these conditions?

There you go, at 6' you only need 2-4 W/channel to reach 90 dB with these speakers and you still have dynamic headroom of about 12-15 more. That's not a rock concert, but you can visit the guy with Cerwin-Vega's for that.


- Val

Quote:
Originally Posted by oztech /forum/post/14209371


The more efficient the less power required to be as loud and 2db will lighten the load on receiver but at 6ft i would go for more efficient.

Why is it a "but"? I think you meant to say something else..
 
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