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dodgerblue
02-04-2005, 11:33 PM
Hello. I've got beginner's questions concerning subwoofers and bass in general. I have a NAD 370 amp and CBM 170s. I don't listen to music at high volume levels; e.g., my volume control knob never goes beyond the 9:00 position and mostly it's at around 8:00. I'm thinking about getting a subwoofer, but I'm wondering if they kick in at lower volumes, or do I have to turn up the juice to activate the subwoofer. If the latter is true, then maybe they're not for me.

Also, if a speaker has a frequency range of 60hz-20khz, does this mean that tones of 40hz on a CD are absent during playback, or do you still hear something? A thank you ahead of time to anyone that may care to answer such elementary questions.

bamputin
02-05-2005, 03:58 AM
yeah you still hear the lower end of the bass, but the loudness decreases. so relative to everything else that can be happening at one time in music, the bass is a lot quieter. so when people say 'how low do they go' what they REALLY mean is 'what's the lowest they'll perform well at'. speaker manufacterers generally specify a hz range, +/- db. without that qualifier it's a useless measurement (you could say that the cbm170's do 20hz-20khz without specifying the db accuracy!)

bamputin
02-05-2005, 04:00 AM
and to answer your question - yes if it's a good sub you will be able to tell the difference even at your 'quiet' listening preference.

Lou-the-dog
02-05-2005, 06:49 AM
Ditto what Bamputin said. Alot of subs have their own amplifier and internal crossover and most recievers have bass management and individual speaker level adjustments. You will be able to tune to your liking no matter what your amp/reciever's gain knob is set at.

Randy

Kpt_Krunch
02-05-2005, 08:43 AM
DB - one other thing - 'most' music doesn't have a lot of bass below 40 or 50 hz. If your setup is used for H/T as well as music listening, then I would definitely get a sub, but if it is strictly for music listening, and at a low volume at that - the price to performance of what you'll get may not be worth it. I would buy a sub that comes with a 15 or 30 day return policy no questions asked. This way you can judge for yourself if the expense is worth it or not.

dodgerblue
02-05-2005, 09:00 AM
Thanks to all for your replies. I'm impressed at how quickly I can get some help. Learned a few things this morning. I don't have an HT and not likely to in the near future, so I'll have to consider whether it is worth it to get a sub. I guess my thought was that I might be missing some low-end information in my music; I listen to a wide range of musci from classical to zeppelin, but not hip-hop or rap.
Your responses did generate some other beginner's questions. What does it mean when a manufacturer states so and so +/- db following a Hz or frequency range? Is a lower number better? db is loudness right? Why is then that on some receivers, the louder you turn up the volume, the db numbers decrease on the digital display?
Gotta run. I'll check in again later for your answers. Thanks again.

Quinn
02-05-2005, 09:23 AM
+/- dB means how far off a flat response a speaker or sub is over the given range of Hertz.

For classical music stand up bass, the lower ranges of the piano and organ are likely missing. There is another thread here on the forum with links showing the range of some intruments. http://forum.ascendacoustics.com/showthread.php?t=700

The other thing regarding bass and low volumes is the Fletcher-Munson curves. I may be over simplifying but bass isn't heard as well at lower volumes as higher volumes. That is why receivers used to have a loudness button to boost bass at low volumes.

http://www.phys.unsw.edu.au/~jw/graphics/Fletcher-Munson.gif

Kpt_Krunch
02-05-2005, 09:31 AM
What does it mean when a manufacturer states so and so +/- db following a Hz or frequency range?

You'll often see something like 35hz to 20 khz +/- 3dB's which means in the stated range, a certain frequency can be 3 dB's louder or 3 dB's lower than other frequencies at the same level. An increase of 3 dB's is about twice as loud as the rest, and a decrease of 3dB's is about the same ratio the other way. Usually how it works is the lower the frequency, the more it falls in the '-' category, and the higher the frequency, the more it falls in the '+' category. A speaker manufacturers quest is to maintain a flat line through a certain frequency range. Human hearing in general is only 20hz to 20 khz - so a 'perfect' speaker in terms of reproducing frequencies would be flat (+/- 0 db's) from 20hz to 20 khz. This is why Bamputin's comment of no +/- rating with a frequency range is spot on! If you look at David F's frequency charts on the 170's you'll see the peaks and valleys (and there are very few of those) in the stated range of the speaker.



Is a lower number better? db is loudness right? Why is then that on some receivers, the louder you turn up the volume, the db numbers decrease on the digital display?


dB's are rated lower to higher. Some receivers, like my H/K use ZERO decibels as a reference point (though not sure what the ref. level is). At ZERO it is far above listening level for me, so as I decrease the volume, I go to negative range. My H/K 520 does +8db's to -74 db's (or something like that). I usually listen between -30db's and -15 db's, depending on the source material (though I have had it up to -5 on older material not recorded very loud).

dodgerblue
02-05-2005, 10:32 AM
Okay. Some more good stuff to mull over! Thanks. Now it all makes sense when I read specs. I once saw a pretty small speaker claim to go 50-20kHz with no +/- dB spec and only a 4.5" woofer/mid; so, it probably did reproduce the range, but at levels far from flat, right?
As, far as my earlier comment on how the numbers on some displays decrease to 0 as the volume increases, I think I missed the fact that the numbers were negative to start off, so actually they were increasing. Seems counter intuitive to use numbers in this way. Why don't they just start off with 0dB, which would be no decibels or no volume, and increase the values? Oh well.
And going back to subs and low volume listening, turning up the gain on a sub would be like using a loudness button on a receiver, then? The frequency response then is skewed towards the low-end and is far from a flat repsonse, right? I think I get it. You guys have been very helpful. I'm sure I'll come up with more questions, as I read your replies. Good day!
Oh, one other thing. How do you block off and select a quote to include in the reply?

Quinn
02-05-2005, 10:46 AM
The idea of 0 as reference is that you calibrated your system to 0 being reference level of 85dB or 75 dB whichever you subscribe to as being reference level.

When I'm doing quotes like what you see I just add the mark ups and and deleted the rest or if you scroll down when you're posting. The thread is below and I just copy and paste it and put in the quote mark ups. I intentionally misspelled quote in the mark ups so you could see the mark ups.

Kpt_Krunch
02-05-2005, 11:58 AM
The idea of 0 as reference is that you calibrated your system to 0 being reference level of 85dB or 75 dB whichever you subscribe to as being reference level.



Quinn - good explaination. Dodgerblue - as an example, I have set up my H/K receiver to be at 70 dB's (give or take a decible) with each speaker using an analog SPL from Radio Shack. I did it via DVD and my digital connection with the receiver setting at -27. So theortically, at -27 my system will play a DVD at 70 db's. However, in actuality it varies as it is each speaker - one at a time, that I have calibrated, with my sub running a little bit hot. With all of the speakers firing it is louder than 70 db's at -27, though again it varies depending on the source material. This is why I normally run it around -30. So, when I go to -10, I've added 17 dB's in volume or 87 dB's total - to EACH speaker which is much too loud in my room for most material. Hope this makes sense (I'm afraid I'm not very good at explaining things like this at times) but it's the best way I can describe it. I could calibrate at 0, but it would be in the 95 db range at that point for each speaker which is much too loud in my room. You also have to take into account room gain - but that's a totally different subject ;)

Dave G
02-05-2005, 01:31 PM
Dodgeblue,

If I were in your shoes I would get a subwoofer, but it's a judgment call. I also have a NAD C370, but my mains are CMT-340s, not CBM-170s. Even though the 340s extend a bit lower than the 170s (50Hz v. 63Hz), and even though the 340s do sound great without a sub, I've found that a sub adds noticeably and nicely to the "bottom" of the music. It's not as if the music went from bad to good with the sub, it just became nicer. Since you have 170s, the effect might be even more noticeable.

If you'll be using this for HT as well for music, then I agree with Kpt_Krunch that you should get a sub.

Now I have a combined HT and 2 channel music system and already had a sub when I added the C370 to the system, so I didn't have to decide whether to spend more $$ on a sub. It's a bit harder for you. If you do decide to see what a sub can do, then I'd agree with Kpt_Krunch's suggestion that you buy a sub from some place that has a 30-day no questions asked return policy. One possibility would be a Hsu Research sub, which you can purchase from Ascend.

Good luck, and be sure to tell us what you decide to do.

Dave

Lou-the-dog
02-05-2005, 05:14 PM
And going back to subs and low volume listening, turning up the gain on a sub would be like using a loudness button on a receiver, then? The frequency response then is skewed towards the low-end and is far from a flat repsonse, right? I think I get it.

Alot of folks prefer setting the sub a tad hot... maybe 2-4 db. It's all up to your listening preference. I think with your listening preferences adding a SMALL sub might be the ticket for you to try...maybe something like a Hsu STF-1 or even the $100 Dayton sub from Parts Express. I think you would like the results.

Randy

curtis
02-05-2005, 06:41 PM
dodgerblue.......

Because of your name, I am going to assume you are in the Los Angeles area.

I am in Manhattan Beach, and if you would like to experience nuances of your speakers with and without a sub at different listening levels, you are more than welcome to visit.

dodgerblue
02-06-2005, 10:05 AM
Dodgeblue,

I also have a NAD C370, but my mains are CMT-340s, not CBM-170s. Even though the 340s extend a bit lower than the 170s (50Hz v. 63Hz), and even though the 340s do sound great without a sub, I've found that a sub adds noticeably and nicely to the "bottom" of the music. Since you have 170s, the effect might be even more noticeable.

Dave

Since you have a 2-channel system that closely matches mine, your opinion will be seriously considered. Thanks.

dodgerblue
02-06-2005, 10:09 AM
dodgerblue.......

Because of your name, I am going to assume you are in the Los Angeles area.

I am in Manhattan Beach, and if you would like to experience nuances of your speakers with and without a sub at different listening levels, you are more than welcome to visit.


People on this forum sure are knowledgeable and friendly too! I use to live in LA, but now I'm up in the Monterey Bay area. I haven't lived in LA for 20 yrs. now, but do go back and visit my father yearly. If I don't have a sub and I'm down in the area, I'll take you up on that. Thanks! I use to ride my bike from Culver City to Manhattan Beach along the coast. Now I feel like going to Redondo and having some cracked crab!

dodgerblue
02-06-2005, 10:17 AM
Alot of folks prefer setting the sub a tad hot... maybe 2-4 db. It's all up to your listening preference. I think with your listening preferences adding a SMALL sub might be the ticket for you to try...maybe something like a Hsu STF-1 or even the $100 Dayton sub from Parts Express. I think you would like the results.

Randy


Does setting it hot mean to make the bass louder? So subs retrieve lows that smaller speakers can't produce and they also increase the volume. But will it distort bass frequencies?

Someone has suggested the HSU VTF-2, too. I'll look into your suggestions, if a small sub will suffice. Thanks.

dodgerblue
02-06-2005, 10:31 AM
So theortically, at -27 my system will play a DVD at 70 db's. This is why I normally run it around -30. So, when I go to -10, I've added 17 dB's in volume or 87 dB's total - to EACH speaker which is much too loud in my room for most material.


So 0 is all the way up, then, or do some receivers go into positive values?
This means when speakers are tested at 90-95dBs, they are given quite a bit of power and being pushed hard. I think I'll try and see what the 12:00 position sounds like, when no ones home, just to hear the 170s potential. Thanks, Quinn.

Lou-the-dog
02-06-2005, 12:18 PM
Does setting it hot mean to make the bass louder? So subs retrieve lows that smaller speakers can't produce and they also increase the volume. But will it distort bass frequencies?

Someone has suggested the HSU VTF-2, too. I'll look into your suggestions, if a small sub will suffice. Thanks.


Yes. My usage of "hot" is to mean a higher volume (SPL) setting in relation to the setting of your main speakers. You shouldn't be worried about distortion unless it is a very bad sub or even a good one set at a rediculously high setting.

I've got the Hsu VTF-3 MKII and love it. For music only it would be WAY overkill...for me. I have an Ascend 5.1 system and the big sub comes in handy for dynamic movies. For music only, also take a look at the STF-2 which is the same as the VTF-2 less the variable tuning...and will save you a few bucks too.

Randy

Quinn
02-06-2005, 12:28 PM
Thanks, Quinn.

You're welcome. When I want to see how a mark up is done for anything. I hit quote for that post and the mark ups will show up in the text of the message box.

Kpt_Krunch
02-06-2005, 02:49 PM
So 0 is all the way up, then, or do some receivers go into positive values?
This means when speakers are tested at 90-95dBs, they are given quite a bit of power and being pushed hard.

Well DB - I can only answer for my H/K - it goes to +8 I believe. Which at a 70 +36 = 106 dB's per speaker (given the -27dB = 70 dB's / speaker calibrated) would probably cause a bit of hearing damage :)

And yes, when speakers are tested at 90 to 95 dB's, they're given quite a bit of power - but depending on the speaker and the type of power it is getting I wouldn't necessarily say that they are being pushed hard.

dodgerblue
02-07-2005, 10:46 PM
For music only, also take a look at the STF-2 which is the same as the VTF-2 less the variable tuning...and will save you a few bucks too.

Randy

Lou-da-dog. I'll look into the STF-2, since I don't own an HT and use my system for 2-channel solely. If it's as good as the VTF-2, but cheaper, then maybe it's the way to go.

And to everyone else that took the time to educate me on basic audio, a big thanks! I'll keep you posted on my subwoofer decision.

Too bad for the Eagles and Andy Reid. I don't necessarily like the Eagles, but I did go to school with Andy in elementary, Jr. High and John Marshall High. He looks the same.