# 50hz vs 40hz tone. What's the difference?



## impulse (Jul 5, 2014)

For adjusting gains, I can't seem to find an answer to this. What difference does using 50hz tone make over using 40hz? I noticed most recommends online say to use 50hz but curious why the DD-1 only allows for 40hz...I assume there's a reason. The only quote I found was saying that if you use Bass Boost at around 40hz, then use the 40hz tone to adjust gain.

My crossover is 80hz so 40hz would be the half way mark. Does 50hz make more use of my amps power?


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## SilentWrath (May 23, 2017)

I personally like to use whatever frequency is gonna be using the most excursion. This will vary from depending on your sub and enclosure. For my current setup it's 30hz. If you input your sub and enclosure into winisd you can view a graph of excursion vs frequency. 

This way I can set gains based off mechanical limits of the woofer. This only works if you know the sub will not be pushed to thermal limits by the power your amps produces.

Obviously if you clip the signal before you reach xmax you should back the gain down to where it's no longer clipping. 

This probably isn't the correct way to do it, but has worked well for me for years.

Puts flame suit on


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## Weigel21 (Sep 8, 2014)

One would need to ask D'Amore Engineering to find out why exactly they/he opted to use 40Hz and 1kHz for the test tones. 

Honestly, I'm not sure the reason, but given how many amplifiers have bass boosts centered at 40Hz, it could be assumed that was the underlying reason. 

In reality, it depends on the method/device you are using to set your gains and the enclosure being used.As mentioned above, one can opt to set gains to prevent pushing the driver beyond it's Xmax, so as not to hit the Xlim and cause damage to the driver. 

Personally, I don't really like the idea of the DD-1 using those two frequencies. I have used a pocket Scope on an older HU of mine and found that not every frequency is equal. 1kHz and 40Hz could remain clean at a higher level than other frequencies. IIRC, 250Hz produced distortion sooner than any other frequency I tested and was IIRC 3 or so click lower than when the HU produced distortion with 1kHz. And I think 40Hz remained another click or two higher yet. 

Also, I'm not sure, but the DD-1 may be able to detect distortion with any frequency, but only has dummy lights for 40Hz and 1kHz detected.


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## impulse (Jul 5, 2014)

Weigel21 said:


> One would need to ask D'Amore Engineering to find out why exactly they/he opted to use 40Hz and 1kHz for the test tones.
> 
> Honestly, I'm not sure the reason, but given how many amplifiers have bass boosts centered at 40Hz, it could be assumed that was the underlying reason.
> 
> ...


I'll use a pocket O'scope to set gain and will be using a sealed box. Basically ATM I'm gather parts so I'm just trying to plan out a new install is all. Last time I used 50hz @ 0db's but I plan to use -5db's this time because I never felt I was getting my systems full potential.

Now when I do my HU to find the max volume, I'm going to use several frequencies @ 0db's so I can make sure I have a clean signal to my amp. I did consider using a frequency sweep....that way I can see which frequency causes the highest distortion from my HU and note the volume there but I'm sure it's not necessary....a little distortion is good for the soul.


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## Weigel21 (Sep 8, 2014)

A frequency sweep is a good idea. I never though to use such a thing years ago, but do recall people talking of doing such more recently. I think I played 40-50 different frequencies all at 0dB reference. 

Yeah, using a 0dB test tone to set gains would leave a lot of power off the table, as not a lot of songs have any frequencies recorded at 0dB throughout them. And even those that do have such, they are momentary peaks that last milliseconds. 

-5dB should yield a noticeable improvement in output and breathe new life into songs you'd heard with the setup set with 0dB reference tracks.


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## SilentWrath (May 23, 2017)

Is it pretty safe to use -5db? 

I've always used -3db. I only listen to music, no burp tones or "bass tracks". If -5db is considered safe I could probably gain a little output.


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## UncleHungry (Jul 18, 2017)

SilentWrath said:


> Is it pretty safe to use -5db?
> 
> I've always used -3db. I only listen to music, no burp tones or "bass tracks". If -5db is considered safe I could probably gain a little output.




I believe Andy recommends using -10db. So -5 should be fine.


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## DC/Hertz (Nov 27, 2011)

If you set gains unloaded the frequency used don't matter as long as the amp itself can play it. 
The DD-1 only works at 40hz


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## impulse (Jul 5, 2014)

Cool, I won't worry about it then and just use 40hz. It's not like I ever push my volume at max anyway and allegedly my Earthquake subs can do 2.5" inches of peak to peak excursion. Now as a teenager I certainly listened to everything very loud but I have my comfort zone these days. It's a wonder I never blew any amps or speakers as a teen as I knew little to nothing about gain. I remember bridging a 2 ohm load on my RF Punch 60 amp and cranking the gains and bass boost full blast....never blew anything, amp was a tank and I still have it to this day!.



UncleHungry said:


> I believe Andy recommends using -10db. So -5 should be fine.


I read that -10db is best left only for subs and that clipping at high volume will happen from time to time but is much less noticeable on subs. -5db's is considered safe for full range to make use of your amps power and that clipping may happen from time to time but rarely noticeable. 
So my take is that unless your recording was done at 0db's and you crank your volume 100% for any lengthy period of time then you shouldn't have any worries and probably less so if your gear is of good quality.

But I have read posts of people claiming that they use -10db's for all their outputs...likely those like me that rarely push the volume beyond halfway anyhow or stop once it starts to sound off. 0db's is probably recommended the most just purely for the safety aspect plus if they happen to use some junk brand gear that may blow easily or may not be rated anywhere near correct. I know I wouldn't want to be responsible for someone taking my word on something like that.


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## Weigel21 (Sep 8, 2014)

I typically heard -10dB on subs as well. But in your case, you have enough headroom, I don't feel clipping will be an immediate concern, but over driving the sub. . 

The ZR's on the other hand are rated at 85RMS with a recommended power from your amp being upwards of 175RMS, or something around that. Given you have around 200RMS available, it may be possible to push the the setup into clipping, but I'd really like to believe that it'd be louder than you are comfortable with if you were to try to push them that hard. 

Last time I messed with my gains, I just played a 0dB 400Hz test tone and dialed up the gain until the mid buzzed, then dialed it down until it cleared back up. Then for my tweeters, I dialed up the gain for those channels to around the same as the mids and backed it off while playing music to blend. 

Many of songs play loud enough with such, but I do have some that actually leave me wanting more, especially if driving with the windows down. Need to go back and reset my gains, but been too lazy, even though it'd be easy enough. 

My sub stage on the other hand gets plenty loud for me with having used a 0dB reference test tone to set the gain. I'm just running a single Polk MM1540 in a downward firing 2cuft enclosure off an MS-A5001. And should be capable of a solid [email protected] ohms, sub is rated at 425RMS. And for all I know, I'm giving it 200RMS when I crank it up to maximum level while playing music. LOL. 

And yeah, 0dB is the "safe" conservative way to go, but will usually result in lack luster performance for many. Sounds like the days of LOUD music are behind you, so I doubt you'll have issues with clipping, at least not enough to be of any concern.


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## SPLEclipse (Aug 17, 2012)

DC/Hertz said:


> If you set gains unloaded the frequency used don't matter as long as the amp itself can play it.
> The DD-1 only works at 40hz


This. You aren't playing into a reactive load like a sub where impedance will be all over the place. There might be slight differences based on frequency depending on the amp's topology but none of real importance.

The DD-1 uses 40hz because it can only "listen" for harmonics of that frequency. "Distortion" is just a measurement of the harmonics produced by a pure sine tone, in this case 2nd order (80hz), 3rd order (120hz), and so on.

Using anything louder than -10dB for subs can be a pretty big waste of power depending on what you listen to.


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## impulse (Jul 5, 2014)

SPLEclipse said:


> This. You aren't playing into a reactive load like a sub where impedance will be all over the place. There might be slight differences based on frequency depending on the amp's topology but none of real importance.
> 
> The DD-1 uses 40hz because it can only "listen" for harmonics of that frequency. "Distortion" is just a measurement of the harmonics produced by a pure sine tone, in this case 2nd order (80hz), 3rd order (120hz), and so on.
> 
> *Using anything louder than -10dB for subs can be a pretty big waste of power depending on what you listen to*.


Reading this, I think I may do -10db for sub instead of -5. But I do plan to set bass boost first because my music really lacks in the 40hz area and I like the artificial bump because the upper 70-80hz range on my sub sounds overpowering.

Gonna work on it tonight, take out all my old gear and put in all the new stuff but my subwoofer amp is only 300 watts so I need all the power from it I can get.


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## Jeffdachefz (Sep 14, 2016)

the DMM method is just a general guideline. The more appropriate way is to set gains via testing and heat and actually learning the full limits of your system. sub or amp gets too hot, you need to lower it down. If the speaker starts distorting and breaking up, you need to lower it down. If the gear is ice cold, you have a lot left in the tank. If it just gets slightly warm, after 10 mins of play then you are at a good level..

You also have to actively recognize the maximum clean output you have because every song is recorded differently with different volume levels and that affects the pre-amp voltage directly which affects the power thats being put out. Basically you need to ACTIVELY control the gain via head unit volume/sub level or other means each song to get max clean output.

Just setting the gain at a single volume level and leaving it alone like that, only going to that volume level is called passive gain setting which is far from optimal compared to active gain setting.


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