# Griffin Twenty - sub crossover question



## ndurantz (Aug 10, 2008)

Hi All,

I recently got an email from Griffin regarding a new wireless amp they created to integrate with the previous version of Airport Express. I am interested in purchasing this as a portable solution for multiple places in my house, including outdoors. My concern is with the crossover setting for the sub out. It states in the specs - 

High-Pass Filter: 80 Hz 2nd order Linkwitz-Riley applied to L+R channels
Low-Pass Filter: 80 Hz 2nd order Linkwitz-Riley applied to subwoofer output

If I understand correctly, that means that the LPF is 80 Hz and cannot be changed, so if I wanted the amp to send freq. below 80 to my mains, I could not do that, which is ok as my mains are smaller in size. My question is, can I use the crossover on the sub to set it to crossover HIGHER than 80 Hz? For example, one set of speakers I would like to use is specd only to go down to 90 Hz. Would enabling the crossover on the sub and setting it to 90 or even 100 Hz override the 80 crossover in the amp?

Hope that make sense. Thanks for any input you may have. Here is the link to the unit if that will help.


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## Zeitgeist (Apr 4, 2009)

ndurantz said:


> Hi All,
> 
> I recently got an email from Griffin regarding a new wireless amp they created to integrate with the previous version of Airport Express. I am interested in purchasing this as a portable solution for multiple places in my house, including outdoors. My concern is with the crossover setting for the sub out. It states in the specs -
> 
> ...


If I'm understanding you correctly....

The "sub out" on the Twenty will dictate what gets sent to the sub. It doesn't matter if you change the sub crossover above 80hz, The Twenty won't be feeding it any content higher than that 80hz crossover point. 

The only thing that you could do would be to pick a lower crossover frequency (lower than 80hz) on the subwoofer -- but there is no reason why you'd do that. 

I was a little underwhelmed looking at the "Twenty", seems awfully simple (although I understand the market...)


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## ndurantz (Aug 10, 2008)

Zeitgeist said:


> If I'm understanding you correctly....
> 
> The "sub out" on the Twenty will dictate what gets sent to the sub. It doesn't matter if you change the sub crossover above 80hz, The Twenty won't be feeding it any content higher than that 80hz crossover point.
> 
> ...


So a couple of questions in response then.

1) I would assume most amps (not referring to receivers or integrated amps) don't include a *set* crossover then, allowing for the active sub to dictate the crossover? - more flexibility to customize the set-up?

2) Or are sub adjustable crossovers aimed at high-level/speaker wire inputs vs. LFE setups?

Thanks!


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## Zeitgeist (Apr 4, 2009)

Well, that "Twenty" is kind of a unique product in that it has both an crossover AND an integrated amp. It's almost like a barebones receiver.

Amps in a general sense don't normally have a crossover. Receiver and preamps do - and they tend to be configurable for subs.

Most powered subwoofers allow you to then plug the L/R speaker inputs (line level) to it - and then rely entirely on the subwoofer's built in crossover. HOWEVER, the Griffin doesn't have line level speaker outputs...... So that kind of defeats that idea. 

This discussion may be somewhat circular - as there is normally not a lot of reason to use anything other than 80 hz. It's pretty much a standard - and what is recommended by THX.

Do you really want something different than 80 hz?


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## ndurantz (Aug 10, 2008)

Zeitgeist said:


> Well, that "Twenty" is kind of a unique product in that it has both an crossover AND an integrated amp. It's almost like a barebones receiver.
> 
> Amps in a general sense don't normally have a crossover. Receiver and preamps do - and they tend to be configurable for subs.
> 
> ...


Only because one of the speaker sets I will be using with it specs out @ 90 hz (Boston Acoustic Soundware).


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## Zeitgeist (Apr 4, 2009)

That shouldn't be a problem. The difference between 80-90 hz is negligible - maybe not even noticeable. 

The real differences are when you're talking like 80hz vs 120hz or something like that.

At least looking at the Boston Acoustics - Soundware 4-1/2" 2-Way, the 90hz just means that the performance below 90hz is reduced, it doesn't mean that it doesn't function below 90hz. Unfortunately from the specs I've seen, it doesn't even indicate if 90hz is -3 db lower response or what, it only lists "Frequency response" which is awfully vague.


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## ndurantz (Aug 10, 2008)

Zeitgeist said:


> That shouldn't be a problem. The difference between 80-90 hz is negligible - maybe not even noticeable.
> 
> The real differences are when you're talking like 80hz vs 120hz or something like that.
> 
> At least looking at the Boston Acoustics - Soundware 4-1/2" 2-Way, the 90hz just means that the performance below 90hz is reduced, it doesn't mean that it doesn't function below 90hz. Unfortunately from the specs I've seen, it doesn't even indicate if 90hz is -3 db lower response or what, it only lists "Frequency response" which is awfully vague.


Hmmmm. Food for thought for sure. I may jusy go ahead and pick one up to test it out & see what I hear. Thanks!

Sent from my iPhone using HTShack


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## ndurantz (Aug 10, 2008)

Zeitgeist said:


> I was a little underwhelmed looking at the "Twenty", seems awfully simple (although I understand the market...)


I have this product in my cart, ready to purchase and your "underwhelmed" statement has given me pause. I am mainly looking to use this outdoors to play music and provide sound for movies we'll show outside in the summer, so I am not looking to spend a bunch of $$. Did you have another product in mind that would provide a small footprint, easily portable that allowed a sub out for some bass rumble for movies? If so, I would be interested in checking it out. Thanks!


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## Zeitgeist (Apr 4, 2009)

I think that it might be a perfect fit for some people --- if you use it as intended. I just wish it had a little more flexibility (but that's my personal opinion).

If you stick with the 80hz crossover, I'm sure it'll be perfectly fine. Depending on the return policy, you might want to purchase it and see if you like it.

I really don't know of any similar products. I think the wireless arena is still somewhat limited - maybe someone else can suggest something.


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## ndurantz (Aug 10, 2008)

Zeitgeist said:


> I think that it might be a perfect fit for some people --- if you use it as intended. I just wish it had a little more flexibility (but that's my personal opinion).
> 
> If you stick with the 80hz crossover, I'm sure it'll be perfectly fine. Depending on the return policy, you might want to purchase it and see if you like it.
> 
> I really don't know of any similar products. I think the wireless arena is still somewhat limited - maybe someone else can suggest something.


I actually just noticed the Emotiva mini-x a 100 and since it has loop pass through, I could hook up a sub. I can always use my iPhone for the wireless option. I think the extra $80 would be worth it.


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## Zeitgeist (Apr 4, 2009)

Emotiva amps generally test extremely well (I own 5 of them now). If you use something else for wireless, I have no doubt you'll be happy with the mini-X A100.


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## ndurantz (Aug 10, 2008)

Zeitgeist said:


> Emotiva amps generally test extremely well (I own 5 of them now). If you use something else for wireless, I have no doubt you'll be happy with the mini-X A100.


And I would be correct that I could run a powered sub off the looped out with no issues? I am doing that with my Parasound Zamp and it seems to work fine.

Sent from my iPhone using HTShack


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## Zeitgeist (Apr 4, 2009)

Yes - the line level out from the A-100 should work perfectly fine with a powered sub as long as the powered sub has an xover (which you said yours does).


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## ndurantz (Aug 10, 2008)

Thanks! Should be here next week, so looking forward to testing out.

Sent from my iPhone using HTShack


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