# Opinions between two subs



## Nostilja (Dec 2, 2011)

Hello All

I have purchased the following two items online.

Denon 650-Watt 5.1-Channel 3D Home Theatre System (DHT-391XP)
and
Precision Acoustics 10" 150-Watt Powered Sub woofer (HD S10)

only to realize the denon already has a sub. Now of course i will be able to test them once i get them, but i would like your valued expert opinion as to which sub should be better.

The denon system comes with the denon DHT-391XP
which is 100 watts
20hz-150hz
8" down firing i believe 


vs the 

Precision Acoustics 10" 150-Watt Powered Sub woofer (HD S10)
10" woofer (front firing)
150 watts 
35Hz-150Hz frequency response


So my concern is that, the denon woofer is only 8" vs the 10" for P.A. subwoofer. im not sure how much of a factor size is, but the HZ seem to be much lower on the smaller sub, is 15 hz that much of a difference. can anyone give me a good understanding of the advantages and disadvantages between the two subs.

Personal experience and reviews are welcome :sn:


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## robbo266317 (Sep 22, 2008)

Welcome to Home Theater Shack.

I am sure there is someone here who can advise on the benefits of each.
A lot of people run multiple subs to smooth out room interactions. Not knowing either sub I cannot say how well they would interact.

Cheers,
Bill.


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## Jungle Jack (Jul 28, 2009)

Hello,
Given you have purchased a Home Theater in a Box, I am not sure you can even connect the Precision Acoustics Subwoofer to it. More than likely, you will need to send back the PA.
Cheers,
JJ


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## Moonfly (Aug 1, 2008)

Jungle Jack said:


> Hello,
> Given you have purchased a Home Theater in a Box, I am not sure you can even connect the Precision Acoustics Subwoofer to it. More than likely, you will need to send back the PA.
> Cheers,
> JJ


The separate sub may have a high level connection, so all is possibly not lost. I wouldnt believe that 20hz figure for the small sub one bit, at least not to levels that are of any real use and cleanly. I would expect the larger sub to be cleaner, and especially so if it is only trying to go to 35hz (which is much more realistic a spec anyway), and I would rather have better cleaner bass to a respectable 35 hz than a little fart box straining badly, which is what I expect the smaller sub to do if trying to match the larger sub.

Of course, you need to see if the larger sub can even be connected yet.


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## fusseli (May 1, 2007)

^ indeed. Manufactureres rate sub frequency response for what they call "typical" in-room response, and they don't publish how they obtained their frequency extension. The 20Hz for the 8incher could be a -10dB point in a 10'x10' room. Who knows. This also suggests the 10" subs 35Hz rating is a little more conservative/honest. Also, larger drivers inherently will produce lower distortion while playing low bass anyways.

I'd agree that the 10" is probably a better sub to run, if you can connect it to your system. I'm guessing you should be able to since Denon (good brand) HTIB receiver is hopefully just an entry-level version of their ordinary receivers and won't use a receiver channel to power the sub like some cheap HTIB setups.

Either way I would not recommend trying to run both subs simultanesously, if you'd considered trying that.


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## Nostilja (Dec 2, 2011)

Thanks everyone for the feedback. I though I was bieng smart, don't know why but I figured that because denon sells all of their electronics individually, this wouldn't be considered a htib, I thought it was more like a bundle. What are the dis advantages with Htib systems?

and also what will I need to run the p.a. sub? im assuming all I need is a sub woofer out?
There is are pre outs on this system, a sub out and surround back Rca.


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## Moonfly (Aug 1, 2008)

HTiB systems are usually very budget systems, and designed as an all in one solution. You cant usually add or take away from them and they dont always run normal configurations and sometimes the sub will run at higher frequencies to normal and things like this.

Once you get to a certain level, it make more sense for manufacturers to sell things separately, not least as many people like to exercise their right to choice, and will mix and match speakers/amps/subs etc.

All you should need is a sub out, but that may be intended for the sub that comes with the system, meaning you would likely have to make a choice as to which one to run. If the larger sub truly is a p.a sub, that would explain why it only goes to 35hz. One good thing about it though is that it will likely be plenty loud, so you wont have issues with a sub that sounds like it is straining.


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## fusseli (May 1, 2007)

^ The brand of his sub is Precision Acoustics, hence P.A.

Sounds like you're good to go since the Denon receiver has the rca for the sub pre-out (again, good choice on buying a denon package). That's all you'll need to connect your sub. When you configure your receiver, set all of your speakers to the "small" setting and try crossovers of 80-150Hz and see what sounds best to you. You should disable the subs onboard crossover to allow the receiver to take care of it. Similarly, toggle the subs phase setting to see what sound best for each crossover point you try.


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## Nostilja (Dec 2, 2011)

Thank you for the advice guys, once I receive it I will let you know my impressions.

I have a second question,

I have 2 Sony bookshelf speakers that are 8 ohms , and can handle 100 watts.

The AVR-391 receiver is rated 75W + 75W (8ohms thd 0.08%) and 110 W + 110 W (6 ohms thd 0.7%)

Would it be possible to run these speakers with the system? What are your suggestions?


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## MikeBiker (Jan 3, 2010)

Those speakers would work without any problems. Whether on not they sound good depends upon the quality of the speaker components, the room acoustics and what you expect.


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## Nostilja (Dec 2, 2011)

Wouldn't the amp be too weak to power these speakers? I thought I would need 100 watts at 8ohms for them to work properly.

And yes I understand what you mean about the quality of the speakers. Since the speakers that come with the system are very small, I will be comparing them to see which sound better. i just wanted to make sure i dont blow out my amp or those speakers because the watts dont match.


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## Jungle Jack (Jul 28, 2009)

Nostilja said:


> Thank you for the advice guys, once I receive it I will let you know my impressions.
> 
> I have a second question,
> 
> ...


Hello,
Just as Mike said, there should be no issues with using the Sony's with your Denon.
Cheers,
JJ


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## MikeBiker (Jan 3, 2010)

Nostilja said:


> Wouldn't the amp be too weak to power these speakers? I thought I would need 100 watts at 8ohms for them to work properly.
> 
> And yes I understand what you mean about the quality of the speakers. Since the speakers that come with the system are very small, I will be comparing them to see which sound better. i just wanted to make sure i dont blow out my amp or those speakers because the watts dont match.


The wattage number of the speakers is pretty much meaningless. It is the maximum power that the speakers can stand. The receivers amps can drive an 8 ohm load with no problems. 100 watts into those speakers would most likely be louder than you would want.


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## Nostilja (Dec 2, 2011)

MikeBiker said:


> The wattage number of the speakers is pretty much meaningless. It is the maximum power that the speakers can stand. The receivers amps can drive an 8 ohm load with no problems. 100 watts into those speakers would most likely be louder than you would want.


Okay I understand. is there a guide on the forum that can help me understand how wattage and speakers work?


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## MikeBiker (Jan 3, 2010)

Nostilja said:


> Okay I understand. is there a guide on the forum that can help me understand how wattage and speakers work?


It's all done with voodoo, magic and mirrors. The speaker manufactures come up with a number that they want to publicize. There may, or may not, be some science/actual data behind the numbers. Who knows. All speakers have an impedance that varies quit a bit over frequency. The manufacturer picks a number (usually an eyeball of the data) and it gets published. The wattage is a mythical number. It does not specify if that is for an impulse spike or a steady state power. Without knowing the efficiency of the speaker, the rated wattage is pretty much meaningless. Most music/movie listening is done with much less than 10 watts from the amps. You will know when you are putting too much power either into the speakers or out of the amp because the sound will instantly become horrible.


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## Nostilja (Dec 2, 2011)

MikeBiker said:


> It's all done with voodoo, magic and mirrors. The speaker manufactures come up with a number that they want to publicize. There may, or may not, be some science/actual data behind the numbers. Who knows. All speakers have an impedance that varies quit a bit over frequency. The manufacturer picks a number (usually an eyeball of the data) and it gets published. The wattage is a mythical number. It does not specify if that is for an impulse spike or a steady state power. Without knowing the efficiency of the speaker, the rated wattage is pretty much meaningless. Most music/movie listening is done with much less than 10 watts from the amps. You will know when you are putting too much power either into the speakers or out of the amp because the sound will instantly become horrible.


Well after taking a second look at the specs of the subs, I realized that the Watts for the subs are listed as Dynamic power. From the way other companies display their information, dynamic power is double the actual wattage, 
so the P.A Sub is only 75 watts 
http://precision-acoustics.com/hds10.html

and the Denon 50 watts.
http://ca.denon.com/DocumentMaster/US/DHT-391XP_Lit707.pdf

:crying: well that ruined my day.

How can best buy sell a 150 watt dynamic power sub for 300 dollars? :foottap: In their product description it does not mention that its dynamic, its only once you go check on the Precision acoustics website that you find out its dynamic.

Other companies such as infinity or Boston acoustics sell subs for about the same price with 300 watts dynamic.

Me thinks mes gona return the sub. Does anyone think there is any hope at this point? should I even test it out? Any thoughts?

And is it normal for companies to rate their subs using dynamic power? Because the amp specs dont seem to be in dynamic. I am not even sure any more. this is proving to be more difficult then I thought.


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## Nostilja (Dec 2, 2011)

Does anyone have opinions on the Boston Acoustics 10" 100-Watt Subwoofer (CSUB10B)


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## Jungle Jack (Jul 28, 2009)

Nostilja said:


> Does anyone have opinions on the Boston Acoustics 10" 100-Watt Subwoofer (CSUB10B)


Hello,
BA makes quality Subwoofers. I do think you get far more value from the Internet Direct Brands like HSU Research, SVS, eD, et al.
Cheers,
JJ


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## KalaniP (Dec 17, 2008)

Nostilja said:


> Does anyone have opinions on the Boston Acoustics 10" 100-Watt Subwoofer (CSUB10B)


100 watts is not very much power for a sub, IMO. If budgetary limits force a low end sub, however, it's probably an ok way to go.


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