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7270 sub too small? clipping/protection

stefan75, modified 6 Years ago.

7270 sub too small? clipping/protection

Youngling Posts: 16 Join Date: 3/18/17 Recent Posts
My homecinema room is 8x5x3m... with 1038a mains, 1038ac center and 1037b rears. I've been testing a 7270 sub and the results have been quite ok. But in some movies like Interstellar or Tron Legacy it keeps turning yellow/red (clipping/protection). My surround processor only has analog audio out so I'm using a Behringer Ultramatch 2496 to convert the sub channel to AES/EBU. The Ultramatch has a visual input gain control/display, so I can keep an eye on the levels. Setting the -20dB AES dip switch on the 7270 helped with clipping/protection, but it still happens too often.

The 7270 is set to defaults (dip switch down) except:
LFE in use = YES
System Level = -20dB

Do I have to change another setting, or is the 7270 just too small for my room (only 250W)?

I'm thinking of buying a 7370 (analog and 400W), will it be strong enough and without clipping?
Or should I wait for the 7371 (dual 12")?
ilkka-rissanen, modified 6 Years ago.

Re: 7270 sub too small? clipping/protection

Yoda Posts: 2564 Join Date: 3/23/09 Recent Posts
Hi,

Our subwoofer recommendation for a 1038 based 5.1 system is 2x 7271A so no wonder that you are clipping your single 7270A. Unfortunately a single 7370A won't be enough either. Dual subwoofers will you 6 dB more maximum SPL over a single unit so if you are only clipping your single 7270A occasionally, then probably 2x 7370A would be enough for you. But please remember that your main monitors have 15 inch woofers in them. It is unrealistic that you could have only single 12 inch as a subwoofer! :shock:
stefan75, modified 6 Years ago.

Re: 7270 sub too small? clipping/protection

Youngling Posts: 16 Join Date: 3/18/17 Recent Posts
Hey Ilkka, thanks for the info.

My digital surround processor lets me fine tune the bass management.
I leave the 5 channels untouched (full), but low pass filter the LFE channel.
The interesting thing was, when set to 40Hz the 7270 was too quite/weak.
After setting the low pass to 33Hz the effects (explosions etc.) were much more powerful.
I'm guessing the sub could focus his limited energy on less frequency.

I read in the manual about the performance gain when positioning the sub close to a wall.
I really want to try that but I'd have to rearange some furniture/devices first.

cu
ilkka-rissanen, modified 6 Years ago.

Re: 7270 sub too small? clipping/protection

Yoda Posts: 2564 Join Date: 3/23/09 Recent Posts
LFE channel's typical upper bandwidth limit is 120 Hz so if you low passing it now at 33 Hz, you are missing large portion of its content. I am sorry to say but there is no magic trick that would help a single 7270 to provide enough SPL in your system no matter how you position it. Only effective way to create more SPL is to buy bigger sub(s). :)
stefan75, modified 6 Years ago.

Re: 7270 sub too small? clipping/protection

Youngling Posts: 16 Join Date: 3/18/17 Recent Posts
Don't worry, I'm just using/testing the 7270 until it's clear which size I really need.

Let's say I have the 1038 LCR, 1037 RR/RL and two 7370.
What crossover/bassflow would you recommend in 5.1 (bluray movie) mode?
ilkka-rissanen, modified 6 Years ago.

Re: 7270 sub too small? clipping/protection

Yoda Posts: 2564 Join Date: 3/23/09 Recent Posts
Hi,

Since you have very capable mains and surrounds which do not necessarily require bass management, I would just run them large and have the subwoofer produce only the LFE channel. But as I wrote earlier, a single 7270 just can't cope with those speakers if you want to play them loud.

Your speakers have 2x15", 2x12" and 2x10" woofers in them and your subwoofer has only single 12". It is an unrealised equation :?
stefan75, modified 5 Years ago.

RE: Re: 7270 sub too small? clipping/protection

Youngling Posts: 16 Join Date: 3/18/17 Recent Posts

I'm curious, how is the overload protection done...

do you analyse the signal?

do you measure the driver movement?

do you measure the amp usage?

jani-oksanen, modified 5 Years ago.

RE: Re: 7270 sub too small? clipping/protection

Jedi Master Posts: 449 Join Date: 3/30/17 Recent Posts

Hi Stefan,

Answer to your question can be found from link below:

https://www.genelec.com/key-technologies/protection-circuitry

Best regards,
Jani Oksanen
Customer Support Team

johnvnross, modified 5 Years ago.

RE: 7270 sub too small? clipping/protection

Youngling Posts: 3 Join Date: 11/4/12 Recent Posts

Hi there.  I also have 1038's and 1038ac as my home cinema LCR. My 7071 / 7070 provide enough bass for my 6m x 5m x 2.40m cinema.  Best wishes  john.

 

 

 

 

stefan75, modified 5 Years ago.

RE: 7270 sub too small? clipping/protection

Youngling Posts: 16 Join Date: 3/18/17 Recent Posts
john ross:

Hi there.  I also have 1038's and 1038ac as my home cinema LCR. My 7071 / 7070 provide enough bass for my 6m x 5m x 2.40m cinema.  Best wishes  john.

 

 

 

 

While I'm waiting for the new successor of the 7370... I might be tempted to get a used 7071 (missed an auction recently for < $1000.. NOOO~~~).

thanks

thuety (avsforum)


 

stefan75, modified 5 Years ago.

RE: 7270 sub too small? clipping/protection

Youngling Posts: 16 Join Date: 3/18/17 Recent Posts

Couldn't wait for the new sub any more... got a used 7071.

First tests: nice :)

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johnvnross, modified 4 Years ago.

RE: 7270 sub too small? clipping/protection

Youngling Posts: 3 Join Date: 11/4/12 Recent Posts
Are you happy?

Attachments: