MOTU Issue: What’s the difference between +4 or -10 inputs?
Audio line levels are referenced at +4 or -10 db. +4 is more common among high end studio equipment, -10 is found in high end studio equipment, and is also the standard for consumer electronics. The difference is the amount of gain. The idea is that the higher the signal gain, the lower the noise floor. Modern gear is much better quality than a few years ago, so noise is not as much a problem as it used to be.
If you send a +4db signal into a -10 db input, you can overload the -10 db input with too much gain. This will cause distortion. The solution to this is to carefully monitor the signal. If the gain is to hot, you will need to attenuate the signal. Attenuation can be achieved with a simple volume control. Use a channel from a mixer, a pre amp, or even a compressor to do this.
Likewise, a -10 db signal going into +4 db inputs will not have enough gain, and there could be noise introduced (the 2408 has -10 and +4 db outputs). If you must send a -10 db signal to a +4 db input, it’s a good idea to add gain to the signal to make the levels match. Once again, a mixer channel or preamp will do the job.
With the latest PCI-324 Driver and PCI-324 CueMix Console, you now have the ability to boost the individual inputs of any Motu Rack by 6 or 12 db.
When you need help, Sweetwater has the answers!
Our knowledge base contains over 28,000 expertly written tech articles that will give you answers and help you get the most out of your gear. Our pro musicians and gear experts update content daily to keep you informed and on your way. Best of all, it’s totally FREE, and it’s just another reason that you get more at Sweetwater.com.
Offer applies only to single-receipt qualifying purchases. Select manufacturers may require that only the manufacturer’s products qualify towards the minimum purchase amount needed to be eligible for promotional financing. Otherwise, an invoice that meets the minimum purchase amount and contains at least one qualifying manufacturer product is eligible for promotional financing. No interest will be charged on promo purchase balance, and equal monthly payments are required on promo purchase until it is paid in full. The payments equal the amount financed divided by the number of months in the promo period, rounded up to the next whole dollar. These payments may be higher than the payments that would be required if this purchase was a non-promo purchase. During the last month(s) of the promo period the required monthly payment may be reduced due to the prior months’ rounding. Regular account terms apply to non-promo purchases. New Accounts as of 07/31/2025: Purchase APR is 34.99%. Penalty APR is 39.99%. Min Interest Charge is $2. Existing cardholders: See your credit card agreement terms. Subject to credit approval.
Offer applies only to single-receipt qualifying purchases. No interest will be charged on the promo balance if you pay it off, in full, within the promo period. If you do not, interest will be charged on the promo balance from the purchase date. The required minimum monthly payments may or may not pay off the promo balance before the end of the promo period, depending on purchase amount, promo length and payment allocation. Regular account terms apply to non-promo purchases and, after promo period ends, to the promo balance. New Accounts as of 07/31/2025: Purchase APR is 34.99%. Penalty APR is 39.99%. Min Interest Charge is $2. Existing cardholders: See your credit card agreement terms. Subject to credit approval.
The estimated required monthly payment shown which excludes taxes and delivery equals the amount financed divided by the number of months in the promo period, rounded up to the next cent. During the last month(s) of the promo period the required monthly payment may be reduced due to this rounding. These payments apply only with the financing offer shown. If you make these payments by the due date each month, you should pay off this amount financed within the promo period, if it is the only balance you are paying off. If you have other balances on your account, this payment will be added to any other minimum monthly payments.
Applies only to select items from this manufacturer. Ask your Sweetwater Sales Engineer for more details.