Dr. R.C. Sproul is Reformed scholar and theologian, founder (and president) of Ligonier Ministries and president of Ligonier Academy.  The following is what he wrote (in italic, underlined emphasis is mine) on double predestination, which is taken from:

http://www.the-highway.com/DoublePredestination_Sproul.html

In the article Dr. Sproul describes what he calls as distortion of double predestination:

The distortion of double predestination looks like this: There is a symmetry that exists between election and reprobation. God WORKS in the same way and same manner with respect to the elect and to the reprobate. That is to say, from all eternity God decreed some to election and by divine initiative works faith in their hearts and brings them actively to salvation. By the same token, from all eternity God decrees some to sin and damnation (destinare ad peccatum) and actively intervenes to work sin in their lives, bringing them to damnation by divine initiative. In the case of the elect, regeneration is the monergistic work of God. In the case of the reprobate, sin and degeneration are the monergistic work of God. Stated another way, we can establish a parallelism of foreordination and predestination by means of a positive symmetry. We can call this a positive-positive view of predestination. This is, God positively and actively intervenes in the lives of the elect to bring them to salvation. In the same way God positively and actively intervenes in the life of the reprobate to bring him to sin.

This distortion of positive-positive predestination clearly makes God the author of sin who punishes a person for doing what God monergistically and irresistibly coerces man to do. Such a view is indeed a monstrous assault on the integrity of God. This is not the Reformed view of predestination, but a gross and inexcusable caricature of the doctrine. Such a view may be identified with what is often loosely described as hyper-Calvinism and involves a radical form of supralapsarianism. Such a view of predestination has been virtually universally and monolithically rejected by Reformed thinkers.

Dr. Sproul stated that Reformed position of double predestination should be understood to be positive-negative predestination:

In sharp contrast to the caricature of double predestination seen in the positive-positive schema is the classic position of Reformed theology on predestination. In this view predestination is double in that it involves both election and reprobation but is not symmetrical with respect to the mode of divine activity. A strict parallelism of operation is denied. Rather we view predestination in terms of a positive-negative relationship.
In the Reformed view God from all eternity decrees some to election and positively intervenes in their lives to work regeneration and faith by a monergistic work of grace. To the non-elect
[the Reprobate] God withholds this monergistic work of grace, passing them by and leaving them to themselves. He does not monergistically work sin or unbelief in their lives.

He explains further why God does not monergistically work sin or unbelief in Reprobate’ lives

If God, when He is decreeing reprobation, does so in consideration of the reprobate’s being already fallen, then He does not coerce him to sin. To be reprobate is to be left in sin, not pushed or forced to sin.

What Dr. Sproul explains on positive-negative double predestination could be expressed in the following analogy:

All men are like damaged cars on conveyor belt that will bring them to crushing machine.  There is nothing those cars can do to save themselves – they are not even aware that they will be crushed. They don’t have a will to be saved let alone make request to be saved.  God is a good mechanic – what He did is He chose some cars unconditionally, i.e. His choice does not depend on their colour, year, type, size, value, mileage, manufacturer, country of origin, degree of damage etc.  He repaired those chosen cars, filled their tanks with gas and drove them home (heaven). During this process those cars gave neither resistance, i.e. no kicking and screaming whatsoever, nor cooperation. Their salvation is monergistic work of the Mechanic.  The damaged cars He did not choose obviously ended up being crushed – there is nothing they can do.  Yet the Mechanic (God) is not responsible for their crushing, they were already damaged and were deemed to be crushed in the first place.  When did the Mechanic make the choice, i.e. which cars He wanted to save and which ones He bypassed?  The supralapsarian Calvinists say it happened before they ended-up damaged on conveyor belts (i.e. before the Fall) while the infralapsarian ones will say He made the choice after they ended-up on conveyor belt.  I am not caricaturing Calvinism here – that is their understanding of being spiritually dead.  In the words of Dr. Sproul:

When we considered in an earlier study our condition of original sin, we used the biblical metaphors of death and slavery. By nature we are born into this world DOA, dead on arrival, spiritually although alive biologically.  We have no inclination whatsoever in our souls towards the things of God – no interest, no passion, no love. We are dead. Because we are spiritually dead, we are slaves to the sinful impulses and lusts that drive our behavior. We are not just participation in sin; such a description is far too weak. The Bible teaches us again and again that we are slaves to sin. Sin is not only in our nature, but it is our master.

Sproul, R.C.: Romans, St Andrew’s Expositional Commentary, page 188-189

The problem with double predestination view, even in positive-negative form, is it does not go in-line with a number of verses from Scripture (Romans 5:18, 1 Corinthians 15:22, Titus 2:11, 2 Peter 3:9).  Reformed systematic theologian, Louis Berkhof (1873 to 1957) argued that “all” or “all men” in those verses should be understood to mean “all in Christ” or (for Titus 2:11) “all classes of men” – otherwise they will support universalism (source: Berkhof: Systematic Theology, published by the Banner of Truth Trust, page 396).  Certainly isolating those verses will promote universalism (God will save all men), which no Christians believe. Yet re-paraphrasing them (i.e. 1 Corinthians 15:22 says “in Christ shall all be made alive”, not “all in Christ shall be made alive”) or forcing them to mean something that one first predefined is not correct either.  Under synergism, which is the view of Catholics and of some Protestants, we can avoid universalism without re-paraphrasing or interpreting those verses to mean something else.  God through Christ takes the initiative to offer salvation to all men, yet they have freedom to either accept or reject this free offer.  Such freedom is denied in monergism – we are like damaged cars that have no such ability.